Poyry's data showed that 60% of the investment would be for low-voltage grids, 10% for substations, 28% for high-voltage grids and 13% for high-voltage transformers.
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Poyry's data showed that 60% of the investment would be for low-voltage grids, 20403% for substations, 28% for high-voltage grids and 2% for high-voltage transformers.
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Classical computers encode information by either applying voltage or not applying voltage to a chip.
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When you put the voltage probe on the paper, it's measuring a current to calculate the voltage.
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Wholesale power travels on high-voltage transmission lines; distribution utilities run the low-voltage grid that connects to customers.
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He commissioned the first rack-mount voltage control filter from Bob Moog in 1964, which drew on Le Caine's voltage-control technology developed earlier with the Sackbut.
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In this monster storm, their calculations indicated that the voltage in the storm was 1.3 billion volts, about ten times more than the biggest voltage measured previously.
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If you want a low-voltage blanket that doesn't get too hot, the Soft Heat Micro-Fleece Low-Voltage Electric Blanket by Perfect Fit is your best bet.
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It features built-in over-voltage, under-voltage, and short-circuit protection for safe charging, and an LED indicator to tell you when your device is actually charging.
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These are the places that gather high-voltage energy from sources like dams or wind farms and transform it into a voltage that a house or business can use.
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" In addition, Tesla says it is testing vehicle systems such as "chassis, the high voltage drive system, and low voltage subsystems such as vehicle controllers, HVAC, infotainment and lighting.
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BESTEK Portable International Travel Voltage Converter Rather than carrying multiple adapters to charge your stuff when you travel overseas, avoid the hassle and grab this BESTEK Portable Voltage Converter.
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That translates to a low voltage because the power of such a motor is a product of voltage and current (P=V*I, one of the fundamental equations in electricity).
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Okay, if it's not obvious — a magnetic surface that has its position controlled by an applied voltage can also be arranged so that its own position changes that voltage instead.
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The company's Medium Voltage business in the Energy Management division, a drag for the past couple of years, returned to growth as selectivity initiatives under the Medium Voltage Rebound program completed.
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Because everything is bigger in China, the country is not building mere high-voltage transmission lines, like those being built (slowly) in the US. It's building ultra high-voltage (UHV) lines.
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Fear and confusion hummed at a high voltage inside Asha.
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They simply plug the low voltage device into the wall.
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There's also an LCD display for showing voltage and current.
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Will the voltage be applied all at once, or gradually?
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That is why electrical power lines work at high voltage.
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The sensors are piezoelectric, meaning they generate voltage when manipulated.
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" The pope attributed the malfunction to a "drop in voltage.
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Voltage converters are pretty much a thing of the past.
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We can, with IR light, put voltage down a neuron.
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It's also engineered with auto-shutdown to keep your appliance and car from getting damaged, along with a host of other safety features like over-voltage, under-voltage, overload, over-current, and overheating protection.
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Most people know power, maybe voltage and frequency, that's about it.
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Solvay has acquired Energain Li-lon high voltage technology from DuPont.
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Trump's attack on the Khans represents another incremental uptick in voltage.
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He was high voltage, with a motor that had no limits.
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The protection diode features a low maximum leakage current of < 22 μA at the working voltage of 21 V, a breakdown voltage of 21 V typical at 2408 mA, and a maximum clamping voltage of 2567 V at 28400 A. The VBUS4153M2415-HT2409 provides transient protection for data lines as per IEC 201‑4‑2 at ± 20 kV (air and contact discharge).
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So the readout at the top of your phone could be based on voltage, "by identifying what the voltage is on a battery, you can get a sense of the state of a charge," said Sadoway.
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However, the chargers and adapters lacked adequate insulation and had improper spacing between the high voltage and low voltage circuits, creating risks of overheating, fire or electrical shocks, Apple charged in a 248 federal court lawsuit.
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Lowering the voltage almost tenfold in this way does, though, make the T1's motor easier to protect and insulate, which in turn makes it cheaper to produce than higher-voltage motors, says Brian Hemond, Indigo's boss.
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More voltage, more medication — and each fiber can carry a different one.
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Ironically, the fan powering Chan's work did not have the correct voltage.
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So, it has to build up high voltage before electrons start moving.
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Superconductors are systems where electrons can travel unimpeded and without applied voltage.
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The company specializes in high-voltage stun batons and various bludgeons. Cool!
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High-voltage fences surrounded the Auschwitz-Birkenau Memorial and Museum in Poland.
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Or, you know, not tinker with the voltage in the first place.
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His band joins him after a few songs, adding the necessary voltage.
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I gave Star Crossed Myth a try — a highly recommended Voltage game.
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In fact, it was from Scorpio, a character from the Voltage Inc.
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But, Jansen says that needing some voltage isn't a handicap, per se.
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She starred in little-seen films like 2009's Crank: High Voltage.
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The overall capacity of the 800V high-voltage battery is 93.4 kWh.
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Still, how the voltage soars when he breaks into full-throttle dancing!
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The voltage in his head is not the same as in ours.
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But the world is messy, and the phone senses random fluctuations in voltage across the rest of the screen, too, so an algorithm determines the biggest, thumbiest-looking voltage fluctuations and assumes that's where she intended to press.
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Philips Hue launched three new products at CES: a wall-mounted cylindrical fixture called Appear, a low-voltage spotlight called the Lily XL, and a low-voltage pedestal light (pictured) as part of the Philips Hue Econic line.
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This is because not every country operates under the same voltage and plugging in a curling iron that is not made for the proper voltage can cause fuse shortages and can fry your hair tool, rendering it unusable.
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" A federal appeals court agreed that Voltage should not pay Rogers fees for its Norwich order in May of this year, calling the fees "a multi-million dollar barrier between [Voltage] and the starting gate for their legal proceedings.
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Power plants make the juice and ship it out over high voltage wires.
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Ultra-high-voltage direct-current (UHVDC) connectors are better suited to such spans.
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It only fires when that voltage (its "membrane potential") exceeds a certain threshold.
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Its advantages over Lithium Ion batteries were (and still are) increased cell voltage.
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There are safety issues, too — Tether-tenna runs off a high-voltage cable.
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Rated Voltage: 120 V~ 60 Hz. Power: 66 W and Energy Star-certified.
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Electrical voltage spikes caused by a windshield washer pump can cause short circuits.
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Or the first responder who is unaware might get shocked by the voltage.
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He manipulates the pitch by controlling the speed and voltage of each drive.
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This is important as some older houses have less voltage than newer homes.
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That looks like some serious voltage — enough to seriously injure someone or worse.
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The material then relaxes as the voltage is removed and it cools down.
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If the voltage reaches a certain level, the microcontroller fires the Nerf gun.
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You put some serious voltage behind it, and you start making Trump crazy.
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It's more about the immediate gratification of extraordinary fabric and high-voltage cleavage.
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If you are traveling overseas, you'll likely need a dual voltage curling iron.
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He said a voltage differential in the atmosphere was drawing the electrons upward.
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The product is designed to cook foods over a longer period of time at low temperatures and the switches connect to only 1 side of the power line voltage, so there is never a high voltage applied directly across our switches.
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Cut-away view of a voltage portal A voltage portal extends a voltage source to the outside of an electrical enclosure in an encapsulated non-conductive housing designed for a Non-contact voltage detector (NCVD) to sense voltage if placed into the voltage portal.
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The conductors between a voltage source and a load are called lines, and the voltage between any two lines is called line voltage. The voltage measured between any line and neutral is called phase voltage. For example, for a 208/120 volt service, the line voltage is 208 Volts, and the phase voltage is 120 Volts.
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The surge voltage indicates the maximum peak voltage value that may be applied to electrolytic capacitors during their application for a limited number of cycles. The surge voltage is standardized in IEC/EN 60384-1. For aluminum electrolytic capacitors with a rated voltage of up to 315 V, the surge voltage is 1.15 times the rated voltage, and for capacitors with a rated voltage exceeding 315 V, the surge voltage is 1.10 times the rated voltage. For tantalum electrolytic capacitors the surge voltage can be 1.3 times the rated voltage, rounded off to the nearest volt.
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Voltage swell is the opposite of voltage sag. Voltage swell, which is a momentary increase in voltage, happens when a heavy load turns off in a power system.
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In IEC/EN 60384-1 the allowed operating voltage is called "rated voltage" or "nominal voltage". The rated voltage (UR) is the maximum DC voltage or peak pulse voltage that may be applied continuously at any temperature within the rated temperature range. The voltage proof of nearly all capacitors decreases with increasing temperature. Some applications require a higher temperature range.
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Since the average voltage across C1 is VIN, the output voltage (VO) is VS1 \- VIN. If VS1 is less than double VIN, then the output voltage will be less than the input voltage. If VS1 is greater than double VIN, then the output voltage will be greater than the input voltage.
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A voltage portal avoids voltage exposure for workers by extending the voltage source points to the outside of electrical enclosures. Each voltage point resides in an encapsulated non- conductive housing designed to ensure that a NCVD senses voltage if placed into the voltage portal (Fig. 1). Because a voltage portal contains live voltage and mounts on the outside of an electrical enclosure, it must be robust to ensure long term safety. The UL enclosure type rating of the voltage portal must also match the enclosure rating.
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Rated voltage is applied at primary. If the applied voltage is normal voltage then normal flux will be set up. Since iron loss is a function of applied voltage, normal iron loss will occur. Hence the iron loss is maximum at rated voltage.
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There are essentially two types of voltage controllers: single- phase voltage controllers which control voltage of 230 rms, 50–60 Hz power supply, and three-phase voltage controllers which control 400 rms voltage, 50–60 Hz power supply (depending on the country).
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The Olkaria–Lessos–Kisumu High Voltage Power Line is a high voltage electricity power line connecting the high voltage substation at Olkaria, Kenya to another high voltage substation at Kisumu, Kenya.
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The Tororo–Opuyo–Lira High Voltage Power Line is a high voltage electricity power line, connecting the high voltage substation at Tororo, to another high voltage substation at Lira, in Uganda.
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For some capacitor types, therefore, the IEC standard specifies a second "temperature derated voltage" for a higher temperature range, the "category voltage" UC. The category voltage is the maximum DC voltage, peak pulse voltage or superimposed AC voltage that may be applied continuously to a capacitor at any temperature within the category temperature range.
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Cutoff voltage is equivalent to the JFET's pinch-off voltage (Vp) or VGS(off); i.e., the voltage point at which current stops flowing entirely. This similarity is limited, however. The triode's anode current is highly dependent on anode voltage as well as grid voltage, causing it to appear as a voltage source in circuit.
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The Isinya–Singida High Voltage Power Line is a high voltage electricity power line, under construction, connecting the high voltage substation at Isinya, Kenya to another high voltage substation at Singida, Tanzania.
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If the voltage is transferred unchanged (the voltage gain Av is 1), the amplifier is a unity gain buffer; also known as a voltage follower because the output voltage follows or tracks the input voltage. Although the voltage gain of a voltage buffer amplifier may be (approximately) unity, it usually provides considerable current gain and thus power gain. However, it is commonplace to say that it has a gain of 1 (or the equivalent 0 dB), referring to the voltage gain. As an example, consider a Thévenin source (voltage VA, series resistance RA) driving a resistor load RL. Because of voltage division (also referred to as "loading") the voltage across the load is only VA RL / ( RL \+ RA ).
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Figure 1: A simple voltage divider In electronics, a voltage divider (also known as a potential divider) is a passive linear circuit that produces an output voltage (Vout) that is a fraction of its input voltage (Vin). Voltage division is the result of distributing the input voltage among the components of the divider. A simple example of a voltage divider is two resistors connected in series, with the input voltage applied across the resistor pair and the output voltage emerging from the connection between them. Resistor voltage dividers are commonly used to create reference voltages, or to reduce the magnitude of a voltage so it can be measured, and may also be used as signal attenuators at low frequencies.
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Voltage harmonics are mostly caused by current harmonics. The voltage provided by the voltage source will be distorted by current harmonics due to source impedance. If the source impedance of the voltage source is small, current harmonics will cause only small voltage harmonics. It is typically the case that voltage harmonics are indeed small compared to current harmonics.
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Kawanda–Birembo High Voltage Power Line is a high voltage electricity power line, under construction, connecting the high voltage substation at Kawanda, in Uganda to another high voltage substation at Birembo, in Rwanda.
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It may also be followed by a voltage regulator which virtually eliminates any remaining ripple voltage, and adjusts the DC voltage output very precisely to match the DC voltage required by the circuit.
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Polymer e-cap oxide layers are formed for safety reasons at a higher voltage than the rated voltage, called a surge voltage. Therefore, it is allowed to apply a surge voltage for short times and a limited number of cycles. The surge voltage indicates the maximum peak voltage value that may be applied during their application for a limited number of cycles. The surge voltage is standardized in IEC 60384-1.
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A more usual alternative to additional filter components, if the DC load requires very low ripple voltage, is to follow the input filter with a voltage regulator. A voltage regulator operates on a different principle than a filter, which is essentially a voltage divider that shunts voltage at the ripple frequency away from the load. Rather, a regulator increases or decreases current supplied to the load in order to maintain a constant output voltage. A simple passive shunt voltage regulator may consist of a series resistor to drop source voltage to the required level and a Zener diode shunt with reverse voltage equal to the set voltage.
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Bujagali–Tororo–Lessos High Voltage Power Line is a high voltage electricity power line, under construction, connecting the high voltage substation at Bujagali, in Uganda to another high voltage substation at Lessos, in Kenya.
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Suswa–Isinya–Rabai High Voltage Power Line is an operational high voltage (400 kilo Volts) electricity power line connecting the high voltage substation at Suswa, Kenya to another high voltage substation at Rabai, Kenya.
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The Matambo–Phombeya High Voltage Power Line is a planned high voltage electricity power line, connecting the high voltage substation at Matambo, Tete Province, Mozambique to another high voltage substation at Phombeya, Balaka District, Malawi.
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Loiyangalani–Suswa High Voltage Power Line is a high voltage electricity power line in Kenya, connecting the high voltage substation at Loyangalani, in Marsabit County, to another high voltage substation at Suswa, in Narok County.
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High voltage is defined as any voltage over 1000 volts.Kreuger 1991 Vol. 1, pp. 133-137 Those of 2 to 33 kV are usually called medium voltage cables, those over 50 kV high voltage cables.
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The voltage follower adjusts its output current flowing through the load so that to make the voltage drop across the current sensing resistor R equal to the constant input voltage . Thus the voltage stabilizer keeps up a constant voltage drop across a constant resistor; so, a constant current flows through the resistor and respectively through the load. If the input voltage varies, this arrangement will act as a voltage-to-current converter (voltage- controlled current source, VCCS); it can be thought as a reversed (by means of negative feedback) current-to-voltage converter. The resistance R determines the transfer ratio (transconductance).
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Overdrive voltage, usually abbreviated as VOV, is typically referred to in the context of MOSFET transistors. The overdrive voltage is defined as the voltage between transistor gate and source (VGS) in excess of the threshold voltage (VTH) where VTH is defined as the minimum voltage required between gate and source to turn the transistor on (allow it to conduct electricity). Due to this definition, overdrive voltage is also known as "excess gate voltage" or "effective voltage."Sedra and Smith, Microelectronic Circuits, Fifth Edition, (2004) Chapter 4, Overdrive voltage can be found using the simple equation: VOV = VGS − VTH.
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Relation between rated voltage UR and category voltage UC and rated temperature TR and category temperature TC Referring to IEC 60384-1, the allowed operating voltage for polymer e-caps is called the "rated voltage UR". The rated voltage UR is the maximum DC voltage or peak pulse voltage that may be applied continuously at any temperature within the rated temperature range TR. The voltage proof of electrolytic capacitors decreases with increasing temperature. For some applications it is important to use a higher temperature range. Lowering the voltage applied at a higher temperature maintains safety margins.
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Relation between rated and category voltage and rated and category temperature In IEC 60384-1 the allowed operating voltage is called the "rated voltage" UR or the "nominal voltage" UN. The rated voltage is the maximum DC voltage or peak pulse voltage that may be applied continuously at any temperature within the rated temperature range. The voltage proof of electrolytic capacitors, which is directly proportional to the dielectric layer thickness, decreases with increasing temperature. For some applications it is important to use a high temperature range. Lowering the voltage applied at a higher temperature maintains safety margins.
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Relation between rated and category voltage and rated and category temperature Referring to the IEC/EN 60384-1 standard, the allowed operating voltage for electrolytic capacitors is called the "rated voltage UR" or "nominal voltage UN". The rated voltage UR is the maximum DC voltage or peak pulse voltage that may be applied continuously at any temperature within the rated temperature range TR. The voltage proof of electrolytic capacitors decreases with increasing temperature. For some applications it is important to use a higher temperature range. Lowering the voltage applied at a higher temperature maintains safety margins.
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Relation between rated and category voltage and rated and category temperature Referring to IEC/EN 60384-1 standard the allowed operating voltage for tantalum capacitors is called "rated voltage UR " or "nominal voltage UN". The rated voltage UR is the maximum DC voltage or peak pulse voltage that may be applied continuously at any temperature within the rated temperature range TR (IEC/EN 60384-1). The voltage rating of electrolytic capacitors decreases with increasing temperature. For some applications it is important to use a higher temperature range.
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The operating voltage should be at least the maximum specified for the device. In some cases a higher voltage is applied to obtain lifetime acceleration from voltage as well as temperature. To define the maximum permitted voltage stress, the following methods can be considered: # Force 80% of breakdown voltage; # Force six-sigma less than the breakdown voltage; # Set the overvoltage to be higher than the maximum specified voltage. An overvoltage level of 140% of the maximum voltage is occasionally used for MIL and automotive applications.
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Relation between rated and category voltage and rated and category temperature Referring to IEC/EN 60384-1 standard the allowed operating voltage for niobium capacitors is called "rated voltage UR " or "nominal voltage UN". The rated voltage UR is the maximum DC voltage or peak pulse voltage that may be applied continuously at any temperature within the rated temperature range TR (IEC/EN 60384-1). The voltage proof of electrolytic capacitors decreases with increasing temperature. For some applications it is important to use a higher temperature range.
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This provides a large voltage drop across C1 and a relatively small voltage drop across C2. As the majority of the voltage drop is on C1, this reduces the required insulation level of the voltage transformer. This makes CVTs more economical than the wound voltage transformers under high voltage (over 100kV), as the latter one requires more winding and materials.
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In semiconductor diodes, peak reverse voltage or peak inverse voltage is the maximum voltage that a diode can withstand in the reverse direction without breaking down or avalanching. If this voltage is exceeded the diode may be destroyed. Diodes must have a peak inverse voltage rating that is higher than the maximum voltage that will be applied to them in a given application.
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Like voltage-gated sodium channels, voltage-gated calcium channels are also integral membrane proteins found in the plasma membrane. Voltage-gated calcium channels generate action potentials by the same mechanisms as voltage-gated sodium channels. Various voltage-gated calcium channels have been identified in neurons. N- and P/Q-type voltage-gated calcium channels are the primary subtypes found to support synaptic transmission.
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For polymer Al-e-caps the surge voltage is 1.15 times the rated voltage. For polymer Ta-e-caps the surge voltage can be 1.3 times the rated voltage, rounded off to the nearest volt. The surge voltage applied to polymer capacitors may influence the capacitor's failure rate.
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Figure 4: Top: BJT voltage follower Bottom: Small-signal, low-frequency equivalent circuit using hybrid-pi model Figure 5: Top: MOSFET voltage follower Bottom: Small-signal, low-frequency equivalent circuit using hybrid-pi model Other unity gain buffer amplifiers include the bipolar junction transistor in common-collector configuration (called an emitter follower because the emitter voltage follows the base voltage, or a voltage follower because the output voltage follows the input voltage); the field effect transistor in common- drain configuration (called a source follower because the source voltage follows the gate voltage or, again, a voltage follower because the output voltage follows the input voltage); or similar configurations using vacuum tubes (cathode follower), or other active devices. All such amplifiers actually have a gain of slightly less than unity, but the difference is usually small and unimportant.
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Black curve: The limit for open-circuit voltage in the Shockley–Queisser model (i.e., voltage at zero current). The red dotted line shows that this voltage is always below the bandgap. This voltage is limited by recombination.
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Contacts are rated for the current carrying capacity while closed and the voltage breaking capacity when opening (due to arcing) or while open. Opening voltage rating may be an A.C. voltage rating, D.C. voltage rating or both.
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At any instant the output voltage is three times the input voltage.
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The field-effect tetrode can be used as a highly linear electronically variable resistor – resistance is not modulated by signal voltage. Signal voltage can exceed bias voltage, pinch-off voltage, and junction breakdown voltage. The limit is dependent on dissipation. Signal current flows in inverse proportion to the channel resistances.
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The voltage across the capacitor varies above and below the bias voltage. The voltage difference between the bias and the capacitor is seen across the series resistor. The voltage across the resistor is amplified for performance or recording. In most cases, the electronics in the microphone itself contribute no voltage gain as the voltage differential is quite significant, up to several volts for high sound levels.
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Since the grid voltage changes from −1.5V to −0.5V, and the anode resistor voltage drops from 12 to 33 V, an amplification of the signal resulted. The amplification factor is 21: output voltage amplitude divided by input voltage amplitude.
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The voltage clamp allows the membrane voltage to be manipulated independently of the ionic currents, allowing the current–voltage relationships of membrane channels to be studied.
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The electrodes were shaped such that the reverse breakdown voltage was much higher than the forward breakdown voltage. Once the breakdown voltage was exceeded, the 0Z4 switched to a low- resistance state with a forward voltage drop of about 24 V.
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Circuit design for a simple electromechanical voltage regulator. A voltage stabilizer using electromechanical relays for switching. Graph of voltage output on a time scale. In electromechanical regulators, voltage regulation is easily accomplished by coiling the sensing wire to make an electromagnet.
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The maximum achievable phase voltage amplitude in the linear region, ma less than or equal to one, is '. The maximum achievable line voltage amplitude is ' The only way to control the load voltage is by changing the input DC voltage.
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This offset voltage can create offsets or drifting in the operational amplifier. ;Input offset voltage: This voltage, which is what is required across the op amp's input terminals to drive the output voltage to zero.This definition hews to the convention of measuring op-amp parameters with respect to the zero voltage point in the circuit, which is usually half the total voltage between the amplifier's positive and negative power rails. In the perfect amplifier, there would be no input offset voltage.
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When it is lower than the desired voltage, it turns on the switch. When the output voltage is above the desired voltage, it turns off the switch.
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A voltage source is a two-terminal device which can maintain a fixed voltage.An introduction to electronics An ideal voltage source can maintain the fixed voltage independent of the load resistance or the output current. However, a real-world voltage source cannot supply unlimited current. A voltage source is the dual of a current source.
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When input voltage rises, the diode dumps current to maintain the set output voltage. This kind of regulator is usually employed only in low voltage, low current circuits because Zener diodes have both voltage and current limitations. It is also very inefficient, because it dumps excess current, which is not available to the load. A more efficient alternative to a shunt voltage regulator is an active voltage regulator circuit.
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The surge voltage indicates the maximum peak voltage value that may be applied to electrolytic capacitors during their application for a limited number of cycles. The surge voltage is standardized in IEC/EN 60384-1. For tantalum electrolytic capacitors the surge voltage shall be 1.3 times of the rated voltage, rounded off to the nearest volt. The surge voltage applied to tantalum capacitors may influence the capacitors failure rate.
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The voltage clamp is a current generator. Transmembrane voltage is recorded through a "voltage electrode", relative to ground, and a "current electrode" passes current into the cell. The experimenter sets a "holding voltage", or "command potential", and the voltage clamp uses negative feedback to maintain the cell at this voltage. The electrodes are connected to an amplifier, which measures membrane potential and feeds the signal into a feedback amplifier.
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When higher voltage output is needed, a zener diode or series of zener diodes may be employed. Zener diode regulators make use of the zener diode's fixed reverse voltage, which can be quite large. Feedback voltage regulators operate by comparing the actual output voltage to some fixed reference voltage. Any difference is amplified and used to control the regulation element in such a way as to reduce the voltage error.
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These diodes can indefinitely sustain a moderate level of current during breakdown. The voltage at which the breakdown occurs is called the breakdown voltage. There is a hysteresis effect; once avalanche breakdown has occurred, the material will continue to conduct even if the voltage across it drops below the breakdown voltage. This is different from a Zener diode, which will stop conducting once the reverse voltage drops below the breakdown voltage.
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Some high-voltage power supplies provide an analog input or digital communication interface that can be used to control the output voltage. High-voltage power supplies are commonly used to accelerate and manipulate electron and ion beams in equipment such as x-ray generators, electron microscopes, and focused ion beam columns, and in a variety of other applications, including electrophoresis and electrostatics. High-voltage power supplies typically apply the bulk of their input energy to a power inverter, which in turn drives a voltage multiplier or a high turns ratio, high-voltage transformer, or both (usually a transformer followed by a multiplier) to produce high voltage. The high voltage is passed out of the power supply through the special connector and is also applied to a voltage divider that converts it to a low-voltage metering signal compatible with low- voltage circuitry.
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Diodes in the BZX79 serie are used for voltage references or low voltage stabilizers.
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Bridge rectification has a loss of two diode drops. This reduces output voltage, and limits the available output voltage if a very low alternating voltage must be rectified. As the diodes do not conduct below this voltage, the circuit only passes current through for a portion of each half-cycle, causing short segments of zero voltage (where instantaneous input voltage is below one or two diode drops) to appear between each "hump". Peak loss is very important for low voltage rectifiers (for example, 12 V or less) but is insignificant in high-voltage applications such as HVDC power transmission systems.
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If the electrode capacitance is much less than that of the cell, then when current is passed through the electrode, the electrode voltage will change faster than the cell voltage. Thus, when current is injected and then turned off (at the end of a duty cycle), the electrode voltage will decay faster than the cell voltage. As soon as the electrode voltage asymptotes to the cell voltage, the voltage can be sampled (again) and the next amount of charge applied. Thus, the frequency of the duty cycle is limited to the speed at which the electrode voltage rises and decays while passing current.
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The circuit diagram for a simple capacitor voltage transformer A capacitor voltage transformer (CVT or CCVT), is a transformer used in power systems to step down extra high voltage signals and provide a low voltage signal, for metering or operating a protective relay.
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The Mbarara–Nkenda High Voltage Power Line is a high voltage electricity power line, connecting the high voltage substation in the city of Mbarara, in the Western Region to another high voltage substation at Nkenda, also in the Western Region of Uganda.
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Voltage and frequency can be used as signalling mechanisms to balance the loads. In voltage signaling, the variation of voltage is used to increase generation. The power added by any system increases as the line voltage decreases. This arrangement is stable in principle.
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Because of the non-linear characteristics of these devices, the output of a regulator is free of ripple. A simple voltage regulator may be made with a series resistor to drop voltage followed by a shunt zener diode whose Peak Inverse Voltage (PIV) sets the maximum output voltage; if voltage rises, the diode shunts away current to maintain regulation.
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During this charging period, the voltage at b becomes greater than +β Vsat at some point. The voltage at inverting terminal will be greater than the voltage at the non-inverting terminal of the op-amp. This is a comparator circuit and hence, the output becomes -Vsat. The voltage at node a becomes -βVsat due to voltage division.
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All linear regulators require a higher input than the output. If the input voltage approaches the desired output voltage, the regulator will "drop out". The input to output voltage differential at which this occurs is known as the regulator's drop-out voltage. Low-dropout regulators (LDOs) allow an input voltage that can be much lower (i.e.
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Zener diode shown with typical packages. Reverse current -i_Z is shown. Zener diodes are widely used as voltage references and as shunt regulators to regulate the voltage across small circuits. When connected in parallel with a variable voltage source so that it is reverse biased, a Zener diode conducts when the voltage reaches the diode's reverse breakdown voltage.
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Distribution regulation involves a "regulation point": the point at which the equipment tries to maintain constant voltage. Customers further than this point observe an expected effect: higher voltage at light load, and lower voltage at high load. Customers closer than this point experience the opposite effect: higher voltage at high load, and lower voltage at light load.
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An electrical voltage difference is sometimes called an emf. The points below illustrate the more formal usage, in terms of the distinction between emf and the voltage it generates: # For a circuit as a whole, such as one containing a resistor in series with a voltaic cell, electrical voltage does not contribute to the overall emf, because the voltage difference on going around a circuit is zero. (The ohmic IR voltage drop plus the applied electrical voltage sum to zero. See Kirchhoff's voltage law).
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For some capacitor types therefore the IEC standard specifies a "temperature derated voltage" for a higher temperature, the "category voltage UC". The category voltage is the maximum DC voltage or peak pulse voltage that may be applied continuously to a capacitor at any temperature within the category temperature range TC. The relation between both voltages and temperatures is given in the picture at right. Applying a higher voltage than specified may destroy electrolytic capacitors. Applying a lower voltage may have a positive influence on polymer electrolytic capacitors.
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Lowering the voltage applied at a higher temperature maintains safety margins. For some capacitor types therefore the IEC standard specify a "temperature derated voltage" for a higher temperature, the "category voltage UC". The category voltage is the maximum DC voltage or peak pulse voltage that may be applied continuously to a capacitor at any temperature within the category temperature range TC. The relation between both voltages and temperatures is given in the picture right. Lower voltage applied may have positive influences for tantalum electrolytic capacitors.
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For some capacitor types therefore the IEC standard specifies a "temperature derated voltage" for a higher temperature, the "category voltage UC". The category voltage is the maximum DC voltage or peak pulse voltage that may be applied continuously to a capacitor at any temperature within the category temperature range TC. The relation between both voltages and temperatures is given in the picture at right. Applying a higher voltage than specified may destroy electrolytic capacitors. Applying a lower voltage may have a positive influence on electrolytic capacitors.
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7414 datasheet In this case, the common emitter voltage and Q1 collector voltage are not suitable for outputs. Only Q2 collector should be used as an output since, when the input voltage exceeds the high threshold and Q1 saturates, its base-emitter junction is forward biased and transfers the input voltage variations directly to the emitters. As a result, the common emitter voltage and Q1 collector voltage follow the input voltage. This situation is typical for over-driven transistor differential amplifiers and ECL gates.
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Lowering the voltage applied at a higher temperature maintains safety margins. For some capacitor types therefore the IEC standard specify a "temperature derated voltage" for a higher temperature, the "category voltage UC". The category voltage is the maximum DC voltage or peak pulse voltage that may be applied continuously to a capacitor at any temperature within the category temperature range TC. The relation between both voltages and temperatures is given in the picture right. Lower voltage applied may have positive influences for tantalum electrolytic capacitors.
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Aluminum electrolytic capacitors can be applied for a short time with an overvoltage, also called a surge voltage. The surge voltage indicates the maximum voltage value within the temperature range that may be applied during the lifetime at a frequency of 1000 cycles (with a dwell time of 30 seconds and a pause of 5 minutes and 30 seconds in each instance) without causing any visible damage to the capacitor or a capacitance change of more than 15%. Usually, for capacitors with a rated voltage of ≤ 315 volts, the surge voltage is 1.15 times the rated voltage and for capacitors with a rated voltage exceeding 315 volts the surge voltage is 1.10 times the rated voltage.
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Phaseto-phase voltage measurements are established with voltage transformers in both sections of the busbar.
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A 5.5 volt supercapacitor is constructed out of two single cells, each rated to at least 2.75 volts, in series connection Supercapacitors are low voltage components. Safe operation requires that the voltage remain within specified limits. The rated voltage UR is the maximum DC voltage or peak pulse voltage that may be applied continuously and remain within the specified temperature range. Capacitors should never be subjected to voltages continuously in excess of the rated voltage.
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With three times the voltage, thick conductors can be reduced to a third of the cross-section, and at the same time the relative voltage drop can also be reduced to a third. For the same cross-section, the relative voltage drop is now no more than one ninth. The voltage level resulting from these arguments was so close to three times the present voltage that became the automatic choice for the second voltage level.
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Potassium channel KcsA. Voltage-gated potassium channels are another set of voltage-gated channels that play a significant role in the initiation of dendritic spikes. Voltage-gated potassium channels, similar to voltage-gated sodium and calcium channels, facilitate the movement of cations across the plasma membrane. But unlike voltage-gated sodium and calcium channels, the voltage-gated potassium channel moves cations out of the cell thereby having an inhibitory effect on dendritic spike initiation.
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A dual-voltage CPU uses a split-rail design so the processor core can use a lower voltage, while the external Input/Output (I/O) voltages remain at 3.3 volts for backwards compatibility. A single-voltage CPU uses a single power voltage throughout the chip, supplying both I/O power and internal power. As of 2002 Microprocessor#Market statistics, most CPUs are single-voltage CPUs. All CPUs before the Pentium MMX are single-voltage CPUs.
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A capacitive power supply (transformerless power supply) uses the reactance of a capacitor to reduce the mains voltage to a smaller AC voltage. Typically, the resulting reduced AC voltage is then rectified, filtered and regulated to produce a constant DC output voltage. The output voltage is not isolated from the mains. Consequently, to avoid exposing people and equipment from hazardous high voltage, anything connected to the power supply must be reliably insulated.
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Lowering the voltage applied at a higher temperature maintains safety margins. For some capacitor types therefore the IEC standard specify a second "temperature derated voltage" for a higher temperature range, the "category voltage". The category voltage (UC) is the maximum DC voltage or peak pulse voltage that may be applied continuously to a capacitor at any temperature within the category temperature range. The relation between both voltages and temperatures is given in the picture right.
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Similarly, the voltage regulator is programmed to scale the supply voltage in order to achieve the target voltage for the task. DVS systems use a one-to-one mapping of the voltage to frequency to perform the voltage scaling. Frequency-voltage pairs are determined by characterizing the chip's performance under worst-case conditions and stored in a lookup table. If conditions are more favorable, there may be a significant over-supply of power.
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The surge voltage indicates the maximum peak voltage value that may be applied to electrolytic capacitors during their application for a limited number of cycles. The surge voltage is standardized in IEC/EN 60384-1. For niobium electrolytic capacitors the surge voltage shall be not higher than round 1.3 times of the rated voltage, rounded off to the nearest volt. The surge voltage applied to niobium capacitors may influence the capacitors failure rate.
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The Karuma–Kawanda High Voltage Power Line is a high voltage electricity power line, under construction, connecting the high voltage substation at Karuma Hydroelectric Power Station, in the Western Region of Uganda, to another high voltage substation at Kawanda, in the Central Region of Uganda.
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The voltage between the capacitor terminals is linear with respect to the amount of stored energy. Such linear voltage gradient differs from rechargeable electrochemical batteries, in which the voltage between the terminals remains independent of the amount of stored energy, providing a relatively constant voltage.
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A voltage ladder is a simple electronic circuit consisting of several resistors connected in series with a voltage placed across the entire resistor network. Voltage ladders are useful for providing a set of successive voltage references, for instance for a flash analog-to-digital converter.
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The product portfolio for battery systems includes electric high-voltage and low-voltage battery systems on a lithium-ion basis from 12 volt to 900 volt and HV components for an on-board voltage greater than 60 volt as well as high- voltage switch boxes.
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To circumvent this, some power supplies use a linear voltage regulator to maintain the output voltage at a steady value, independent of fluctuations in input voltage and load impedance. Linear regulators can also reduce the magnitude of ripple and noise on the output voltage.
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The Karuma–Juba High Voltage Power Line is a planned high voltage electricity power line, connecting the high voltage substation at Karuma, in Kiryandongo District, in the Western Region of Uganda, to another high voltage substation at Juba, in Jubek State, in South Sudan.
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The voltage balance over the series-connected capacitors is not symmetrical. Passive or active voltage balance has to be provided in order to stabilize the voltage over each individual capacitor.
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Additional to temperature the voltage and current load influence the life time. Lower voltage than rated voltage and lower current loads as well as lower temperature extend the life time.
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The load is not linear due to the transmission system, whose diode rectifier results in power only being able to be extracted over certain voltage levels. Consequently, the DC voltage level limits the amplitude of the generator phase voltage. With a non- linear load the generator phase voltage will reach maximum amplitude which is approximately equal to the DC voltage. When the generator’s phase voltage reaches the level of the DC voltage current starts to flow (power is extracted) from the generator to the DC side of the rectifier.
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Distributed generation, in particular photovoltaics connected at the distribution level, presents a number of significant challenges for voltage regulation. Typical voltage profile expected on a distribution feeder with no DG. This voltage profile results from current through feeders with no DG decreases with distance from the substation. Conventional voltage regulation equipment works under the assumption that line voltage changes predictably with distance along the feeder. Specifically, feeder voltage drops with increasing distance from the substation due to line impedance and the rate of voltage drop decreases farther away from the substation.
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The function of a linear voltage regulator is to convert a varying DC voltage to a constant, often specific, lower DC voltage. In addition, they often provide a current limiting function to protect the power supply and load from overcurrent (excessive, potentially destructive current). A constant output voltage is required in many power supply applications, but the voltage provided by many energy sources will vary with changes in load impedance. Furthermore, when an unregulated DC power supply is the energy source, its output voltage will also vary with changing input voltage.
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Relation between rated and category temperature range and applied voltage The voltage at which the dielectric becomes conductive is called the breakdown voltage, and is given by the product of the dielectric strength and the separation between the electrodes. The dielectric strength depends on temperature, frequency, shape of the electrodes, etc. Because a breakdown in a capacitor normally is a short circuit and destroys the component, the operating voltage is lower than the breakdown voltage. The operating voltage is specified such that the voltage may be applied continuously throughout the life of the capacitor.
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When Π is a cyclic group, the voltage graph may be called a cyclic-voltage graph.
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This plane eliminates voltage gradients and ensures that any fault is cleared within three voltage cycles.
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The M8100 provides illuminated indication of the actual phase difference between generator voltage and busbar voltage.
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A voltage pulse is applied between a conductive AFM tip and the sample. The applied voltage induces the formation of a water bridge between tip and sample whenever the amplitude of the voltage pulse is above a certain threshold voltage. When the liquid meniscus is created the applied voltage pulse causes an oxidation reaction by breaking the covalent bonds in the water molecules.
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Primary distribution voltages range from 4 kV to 35 kV phase- to-phase (2.4 kV to 20 kV phase-to-neutral) Only large consumers are fed directly from distribution voltages; most utility customers are connected to a transformer, which reduces the distribution voltage to the low voltage "utilization voltage", "supply voltage" or "mains voltage" used by lighting and interior wiring systems.
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The analogous bipolar junction transistor circuit may be viewed as a transconductance amplifier or as a voltage amplifier. (See classification of amplifiers). As a transconductance amplifier, the input voltage is seen as modulating the current going to the load. As a voltage amplifier, input voltage modulates the current flowing through the FET, changing the voltage across the output resistance according to Ohm's law.
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High-voltage stack A cascode may also be combined with a voltage ladder to form a high-voltage transistor. The input transistor may be of any low-UCEO type, while the others, acting as stacked linear series voltage regulators, should be able to withstand a considerable fraction of the supply voltage. Note that for a large output-voltage swing, their base voltages should not be bypassed to ground by capacitors, and the uppermost ladder resistor should be able to withstand the full supply voltage. This shows that a linear series voltage regulator is actually a current buffer with its input and output designations swapped.
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Current sources implemented as circuits with series negative feedback have the disadvantage that the voltage drop across the current sensing resistor decreases the maximal voltage across the load (the compliance voltage).
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The peak inverse voltage is either the specified maximum voltage that a diode rectifier can block, or, alternatively, the maximum voltage that a rectifier needs to block in a given circuit.
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PWM is also used in efficient voltage regulators. By switching voltage to the load with the appropriate duty cycle, the output will approximate a voltage at the desired level. The switching noise is usually filtered with an inductor and a capacitor. One method measures the output voltage.
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The Mirama–Kabale High Voltage Power Line is a high voltage electricity power line, connecting the high voltage substation in the town of Mirama Hills, in the Western Region to another high voltage substation in te city of Kabale, also in the Western Region of Uganda.
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The Masaka–Mutukula–Mwanza High Voltage Power Line is a proposed high voltage electricity power line, connecting the high voltage substation at Masaka, in Masaka District, in the Central Region of Uganda, to another high voltage substation at Mwanza, in Mwanza Region, in the Republic of Tanzania.
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The connexon channels have voltage-dependent gates that open or close depending on the difference in voltage between the interiors of the two cells. Gates can also show voltage sensitivity depending on the difference in voltage from the interior and exterior of the cell (i.e. membrane potential).
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A potentiometer is an instrument for measuring voltage or 'potential difference' by comparison of an unknown voltage with a known reference voltage. If a sensitive indicating instrument is used, very little current is drawn from the source of the unknown voltage. Since the reference voltage can be produced from an accurately calibrated voltage divider, a potentiometer can provide high precision in measurement. The method was described by Johann Christian Poggendorff around 1841 and became a standard laboratory measuring technique.
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Since the armature windings of a direct-current or universal motor are moving through a magnetic field, they have a voltage induced in them. This voltage tends to oppose the motor supply voltage and so is called "back electromotive force (emf)". The voltage is proportional to the running speed of the motor. The back emf of the motor, plus the voltage drop across the winding internal resistance and brushes, must equal the voltage at the brushes.
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High voltage resistor divider probe. A voltage divider can be used to scale down a very high voltage so that it can be measured by a volt meter. The high voltage is applied across the divider, and the divider output--which outputs a lower voltage that is within the meter's input range--is measured by the meter. High voltage resistor divider probes designed specifically for this purpose can be used to measure voltages up to 100 kV.
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Current-voltage characteristic of a Zener diode with a breakdown voltage of 3.4 V. Temperature coefficient of Zener voltage against nominal Zener voltage. A conventional solid-state diode allows significant current if it is reverse-biased above its reverse breakdown voltage. When the reverse bias breakdown voltage is exceeded, a conventional diode is subject to high current due to avalanche breakdown. Unless this current is limited by circuitry, the diode may be permanently damaged due to overheating.
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In an OR gate, VF decreases the high voltage level (the logical 1) while in an AND gate, it increases the low voltage level (the logical 0). The feasible number of logic stages thus depends on the voltage drop and difference between the high and low voltages. ;Source resistance :Another problem of diode logic is the internal resistance of the input voltage sources. Together with the gate resistor, it constitutes a voltage divider that causes deviations in voltage levels.
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"Step voltage" is the voltage between the feet of a person standing near an energized grounded object. It is equal to the difference in voltage, given by the voltage distribution curve, between two points at different distances from the "electrode". A person could be at risk of injury during a fault simply by standing near the grounding point. "Touch voltage" is the voltage between the energized object and the feet of a person in contact with the object.
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During the run-down phase, the switch selects the reference voltage as the input to the integrator. The time that it takes for the integrator's output to return to zero is measured during this phase. In order for the reference voltage to ramp the integrator voltage down, the reference voltage needs to have a polarity opposite to that of the input voltage. In most cases, for positive input voltages, this means that the reference voltage will be negative.
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Changing inverter impedances can change voltage fluctuations of DG, meaning inverters have the ability to control DG voltage output. To reduce the effect of DG integration on mechanical grid equipment, transformers and load tap changers have the potential to implement specific tap operation vs. voltage operation curves mitigating the effect of voltage irregularities due to DG. That is, load tap changers respond to voltage fluctuations that last for a longer period than voltage fluctuations created from DG equipment.
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As the substrate terminal of the transistors is not connected to the source terminal, the drain and source terminals are almost equal and the transistors start conducting at a voltage difference between the gate terminal and one of these conducts. One of the switching terminals of the transmission gate is raised to a voltage near the negative supply voltage, a positive gate-source voltage (gate-to-drain voltage) will occur at the N-channel MOSFET, and the transistor begins to conduct, and the transmission gate conducts. The voltage at one of the switching terminals of the transmission gate is now raised continuously up to the positive supply voltage potential, so the gate-source voltage is reduced (gate-drain voltage) on the n-channel MOSFET, and this begins to turn off. At the same time, the p-channel MOSFET has a negative gate-source voltage (gate-to-drain voltage) builds up, whereby this transistor starts to conduct and the transmission gate switches.
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Microinverters protection usually include: anti-islanding; short circuit; reverse polarity; low voltage; over voltage and over temperature.
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The Opuyo–Moroto High Voltage Power Line is a high voltage electricity power line, under construction, connecting the high voltage substation at Opuyo, a southern suburb of the town of Soroti, in the Eastern Region to another high voltage substation at Moroto, in the Northern Region of Uganda.
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The Lira–Gulu–Nebbi–Arua High Voltage Power Line is a high voltage electricity power line, under construction in Uganda. It connects the high voltage substation at Lira, in Lira District, to another high voltage substation at Arua, in Arua District, all in the Northern Region of the country.
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The Mirama–Kikagati–Nsongezi High Voltage Power Line is a planned high voltage electricity power line, connecting the high voltage substation at Mirama Hills, in the Western Region of Uganda, to another high voltage substation at Kikagati Hydroelectric Power Station and continues to end at Nshungyezi Hydropower Station.
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Comparators can also be used as window detectors. In a window detector, a comparator is used to compare two voltages and determine whether a given input voltage is under voltage or over voltage.
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If there is no current the conductors are assumed to be well isolated. # A high voltage test. Again a voltage source is connected but this time the voltage is of several hundred volts. The increased voltage will make the test more likely to find connections that are nearly shorted since the higher voltage will cause the insulation of nearly shorted wires to break down.
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Instead, Moog used recently available silicon transistors — specifically, a transistor with an exponential relationship between input voltage and output current. With this, he created the voltage- controlled oscillator (VCO), which generated a waveform whose pitch could be adjusted by changing the voltage. Moog designed his synthesizer around a standard of one volt per octave. Similarly, he used voltage to control loudness with voltage-controlled amplifiers (VCAs).
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The stability of the output voltage can be significantly increased by using an operational amplifier: center In this case, the operational amplifier drives the transistor with more current if the voltage at its inverting input drops below the output of the voltage reference at the non-inverting input. Using the voltage divider (R1, R2 and R3) allows choice of the arbitrary output voltage between Uz and Uin.
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A zero crossing detector is a comparator with the reference level set at zero. It is used for detecting the zero crossings of AC signals. It can be made from an operational amplifier with an input voltage at its positive input . When the input voltage is positive, the output voltage is a positive value, when the input voltage is negative, the output voltage is a negative value.
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In telecommunication, a disturbance voltage is an unwanted voltage induced in a system by natural or man-made sources. In telecommunications systems, the disturbance voltage creates currents that limit or interfere with the interchange of information. An example of a disturbance voltage is a voltage that produces (a) false signals in a telephone, (b) Noise (radio) in a radio receiver, or (c) distortion in a received signal.
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This effect is used to advantage in Zener diode regulator circuits. Zener diodes have a low breakdown voltage. A standard value for breakdown voltage is for instance 5.6 V. This means that the voltage at the cathode cannot be more than about 5.6 V higher than the voltage at the anode (though there is a slight rise with current), because the diode breaks down, and therefore conduct, if the voltage gets any higher. This, in effect, limits the voltage over the diode.
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SRDs can, therefore, provide very fast voltage transitions by the very sudden disappearance of the charge carriers. ;Stabistors or Forward Reference Diodes : The term stabistor refers to a special type of diodes featuring extremely stable forward voltage characteristics. These devices are specially designed for low-voltage stabilization applications requiring a guaranteed voltage over a wide current range and highly stable over temperature. ;Transient voltage suppression diode (TVS) : These are avalanche diodes designed specifically to protect other semiconductor devices from high-voltage transients.
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Stacked voltage cell measurements illustrate the need for an isolation amplifier. Stacked voltage cell measurements are common with the growing popularity of solar cells and fuel cells. In this application the technician wants to profile the performance of individual series-connected voltages cells, but the need for an isolated amplifier is often overlooked. Each voltage cell (the normal mode voltage) is removed from ground by an amount equal to the sum of the voltage cells below it (the common mode voltage).
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Dynamic voltage scaling is a power management technique in computer architecture, where the voltage used in a component is increased or decreased, depending upon circumstances. Dynamic voltage scaling to increase voltage is known as overvolting; dynamic voltage scaling to decrease voltage is known as undervolting. Undervolting is done in order to conserve power, particularly in laptops and other mobile devices,S. Mittal, "A survey of techniques for improving energy efficiency in embedded computing systems", IJCAET, 6(4), 440–459, 2014.
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The knee- point voltage of a current transformer is the magnitude of the secondary voltage above which the output current ceases to linearly follow the input current within declared accuracy. In testing, if a voltage is applied across the secondary terminals the magnetizing current will increase in proportion to the applied voltage, until the knee point is reached. The knee point is defined as the voltage at which a 10% increase in applied voltage increases the magnetizing current by 50%. For voltages greater than the knee point, the magnetizing current increases considerably even for small increments in voltage across the secondary terminals.
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Representation of a digital buffer A digital buffer (or a voltage buffer) is an electronic circuit element that is used to isolate the input from the output, providing either no voltage or a voltage that is same as the input voltage. It draws very little current and will not disturb the original circuit. It is also called a unity gain buffer because it provides a gain of 1, which means it provides at most the same voltage as the input voltage, serving no amplification function. A voltage buffer has a very high input impedance (the opposition to current flow viewed from the load).
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A distinction should be made between the voltage at the point of supply (nominal voltage at the point of interconnection between the electrical utility and the user) and the voltage rating of the equipment (utilization voltage). Typically the utilization voltage is 3% to 5% lower than the nominal system voltage; for example, a nominal 208 V supply system will be connected to motors with "200 V" on their nameplates. This allows for the voltage drop between equipment and supply. Voltages in this article are the nominal supply voltages and equipment used on these systems will carry slightly lower nameplate voltages.
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A given change in grid voltage causes a proportional change in plate current, so if a time-varying voltage is applied to the grid, the plate current waveform will be a copy of the applied grid voltage. A relatively small variation in voltage on the control grid causes a significantly large variation in anode current. The presence of a resistor in the anode circuit causes a large variation in voltage to appear at the anode. The variation in anode voltage can be much larger than the variation in grid voltage which caused it, and thus the tube can amplify, functioning as an amplifier.
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Cascade of cross-coupled MOSFET voltage doublers (3 stages : 4× multiplier) A voltage multiplier may be formed of a cascade of voltage doublers of the cross-coupled switched capacitor type. This type of circuit is typically used instead of a Dickson multiplier when the source voltage is or less. Dickson multipliers have increasingly poor power conversion efficiency as the input voltage drops because the voltage drop across the diode-wired transistors becomes much more significant compared to the output voltage. Since the transistors in the cross-coupled circuit are not diode-wired the volt-drop problem is not so serious.
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The gas in the bulb ionizes, starting a glow discharge, and its resistance drops to a low value. In its conducting state the current through the bulb is limited only by the external circuit. The voltage across the bulb drops to a lower voltage called the maintaining voltage Vm. The bulb will continue to conduct current until the applied voltage drops below the extinction voltage Ve (point d), which is usually close to the maintaining voltage. Below this voltage, the current provides insufficient energy to keep the gas ionized, so the bulb switches back to its high resistance, nonconductive state (point a).
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A voltage doubler is an electronic circuit which charges capacitors from the input voltage and switches these charges in such a way that, in the ideal case, exactly twice the voltage is produced at the output as at its input. The simplest of these circuits are a form of rectifier which take an AC voltage as input and outputs a doubled DC voltage. The switching elements are simple diodes and they are driven to switch state merely by the alternating voltage of the input. DC-to-DC voltage doublers cannot switch in this way and require a driving circuit to control the switching.
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Electrometers designed for use with ionization chambers may include a high-voltage power supply, which is used to bias the ionization chamber. Solid-state electrometers are often multipurpose devices that can measure voltage, charge, resistance and current. They measure voltage by means of "voltage balancing", in which the input voltage is compared with an internal reference voltage source using an electronic circuit with a very high input impedance (of the order of 1014 ohms). A similar circuit modified to act as a current-to-voltage converter enables the instrument to measure currents as small as a few femtoamperes.
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Low voltage complementary metal oxide semiconductor (LVCMOS) is a low voltage class of CMOS technology digital integrated circuits.
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VKCDB (Voltage-gated potassium Channel DataBase) is a database of functional data about the voltage-gated potassium channels.
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A majority of genetically encoded voltage indicator are based on the C. intestinalis voltage-sensitive domain (Ci-VSD).
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The factor β (RL / RS ) is the current feedback provided by the voltage feedback source of voltage gain β V/V. For instance, for an ideal current source with RS = ∞ Ω, the voltage feedback has no influence, and for RL = 0 Ω, there is zero load voltage, again disabling the feedback.
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The Nkenda–Mpondwe–Beni High Voltage Power Line is a proposed high voltage electricity power line, connecting the high voltage substation at Nkenda, in Kasese District, in the Western Region of Uganda, to another high voltage substation at Beni, in North Kivu Province, in the Democratic Republic of the Congo.
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The high-voltage transmission assets were transferred to the Danish State and later to Energinet.dk at no cost. , nearly all low-voltage (<10 kV) power lines run as underground cables. For medium voltage around 50-60 kV 40% are buried, while 25% of high-voltage (132-400 kV) are ground cables.
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A voltage doubler using ideal switching elements with zero voltage drop will output double this, namely . However, the drain-source voltage drop of a diode-wired MOSFET when it is in the on state must be at least the gate threshold voltage which might typically be .Liou et al., p.
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The output voltage can be continuously regulated within the nominal range. This is a clear benefit against tap transformers where output voltage takes discrete values. Also, the voltage can be easily regulated under working conditions.
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The voltage after breakdown varies only slightly with changing current. This makes the avalanche diode useful as a type of voltage reference. Voltage reference diodes rated more than about 6-8volts are generally avalanche diodes.
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A zeta converter provides an output voltage that is the opposite of the output voltage of a Ćuk converter.
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The operating voltage of the electrode line usually is in the range of approx. 10-20kV (medium voltage range).
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The high voltage propulsion control was replaced with a safer low voltage propulsion control, which utilized battery voltage (32 volts) to control the train's motors. This battery voltage was what would pass through the motorman's control stand and between cars. Tractive effort throughout the train was synchronized by the battery voltage in this way. Meanwhile, each car would respond individually to the battery voltage, by moving its own 600 volt contacts to direct power obtained locally by each car directly from the third rail toward the motors.
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The voltage clamp operates by negative feedback. The membrane potential amplifier measures membrane voltage and sends output to the feedback amplifier; this subtracts the membrane voltage from the command voltage, which it receives from the signal generator. This signal is amplified and output is sent into the axon via the current-passing electrode. The voltage clamp is an experimental method used by electrophysiologists to measure the ion currents through the membranes of excitable cells, such as neurons, while holding the membrane voltage at a set level.
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Villard cascade voltage multiplier. A voltage multiplier is an electrical circuit that converts AC electrical power from a lower voltage to a higher DC voltage, typically using a network of capacitors and diodes. Voltage multipliers can be used to generate a few volts for electronic appliances, to millions of volts for purposes such as high-energy physics experiments and lightning safety testing. The most common type of voltage multiplier is the half-wave series multiplier, also called the Villard cascade (but actually invented by Heinrich Greinacher).
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A simple voltage/current regulator can be made from a resistor in series with a diode (or series of diodes). Due to the logarithmic shape of diode V-I curves, the voltage across the diode changes only slightly due to changes in current drawn or changes in the input. When precise voltage control and efficiency are not important, this design may be fine. Since the forward voltage of a diode is small, this kind of voltage regulator is only suitable for low voltage regulated output.
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In electrical engineering, particularly power engineering, voltage regulation is a measure of change in the voltage magnitude between the sending and receiving end of a component, such as a transmission or distribution line. Voltage regulation describes the ability of a system to provide near constant voltage over a wide range of load conditions. The term may refer to a passive property that results in more or less voltage drop under various load conditions, or to the active intervention with devices for the specific purpose of adjusting voltage.
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A bandgap-based reference (commonly just called a 'bandgap') uses analog circuits to add a multiple of the voltage difference between two bipolar junctions biased at different current densities to the voltage developed across a diode. The diode voltage has a negative temperature coefficient (i.e. it decreases with increasing temperature), and the junction voltage difference has a positive temperature coefficient. When added in the proportion required to make these coefficients cancel out, the resultant constant value is a voltage equal to the bandgap voltage of the semiconductor.
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Measurement starts with charging the capacitor. The voltage has to be applied and after the constant current/constant voltage power supply has achieved the rated voltage, the capacitor has to be charged for 30 minutes. Next, the capacitor has to be discharged with a constant discharge current Idischarge. Then the time t1 and t2, for the voltage to drop from 80% (V1) to 40% (V2) of the rated voltage is measured.
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A cartoon depicting movement of the S4 segment of a voltage sensor in response to depolarization. The voltage sensor domain contains four transmembrane helices, named S1 through S4. The S4 transmembrane helix contains a number of positively charged arginine and lysine amino acid residues. Voltage sensitivity in VSPs is generated primarily by these charges in the S4, in much the same way that voltage-gated ion channels are gated by voltage.
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They frequently also require a switching element that can be controlled directly, such as a transistor, rather than relying on the voltage across the switch as in the simple AC-to-DC case. Voltage doublers are a variety of voltage multiplier circuit. Many, but not all, voltage doubler circuits can be viewed as a single stage of a higher order multiplier: cascading identical stages together achieves a greater voltage multiplication.
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Track lighting is usually combined with directional lamps with reflectors, such as spotlights. These lamps can run under either mains voltage or a lower (often 12V) voltage. It is common to see line-voltage tracks with low-voltage fixtures. For these, each fixture requires a small built-in transformer to operate it.
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A three-phase bank of voltage regulators used to control the voltage on long AC power distribution lines. This bank is mounted on a wooden pole structure. Each regulator weighs about 1200 kg and is rated 576 kVA. Voltage regulators or stabilizers are used to compensate for voltage fluctuations in mains power.
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The voltage clamp uses a negative feedback mechanism. The membrane potential amplifier measures membrane voltage and sends output to the feedback amplifier. The feedback amplifier subtracts the membrane voltage from the command voltage, which it receives from the signal generator. This signal is amplified and returned into the cell via the recording electrode.
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A Zener diode can be applied to a circuit with a resistor to act as a voltage shifter. This circuit lowers the output voltage by a quantity that is equal to the Zener diode's breakdown voltage.
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Capacitance ranges vs. voltage ranges of different capacitor types Capacitance ranges from picofarads to more than hundreds of farads. Voltage ratings can reach 100 kilovolts. In general, capacitance and voltage correlate with physical size and cost.
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The differential pair can be used as an amplifier with a single-ended input if one of the inputs is grounded or fixed to a reference voltage (usually, the other collector is used as a single-ended output) This arrangement can be thought of as cascaded common-collector and common-base stages or as a buffered common- base stage.More generally, this arrangement can be considered as two interacting voltage followers with negative feedback: the output part of the differential pair acts as a voltage follower with constant input voltage (a voltage stabilizer) producing constant output voltage; the input part acts as a voltage follower with varying input voltage trying to change the steady output voltage of the stabilizer. The stabilizer reacts to this intervention by changing its output quantity (current, respectively voltage) that serves as a circuit output. The emitter-coupled amplifier is compensated for temperature drifts, VBE is cancelled, and the Miller effect and transistor saturation are avoided.
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The simplest non- ideal current source consists of a voltage source in series with a resistor. The amount of current available from such a source is given by the ratio of the voltage across the voltage source to the resistance of the resistor (Ohm's law; ). This value of current will only be delivered to a load with zero voltage drop across its terminals (a short circuit, an uncharged capacitor, a charged inductor, a virtual ground circuit, etc.) The current delivered to a load with nonzero voltage (drop) across its terminals (a linear or nonlinear resistor with a finite resistance, a charged capacitor, an uncharged inductor, a voltage source, etc.) will always be different. It is given by the ratio of the voltage drop across the resistor (the difference between the exciting voltage and the voltage across the load) to its resistance.
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Haswell featured a FIVR Some voltage regulator modules are soldered onto the motherboard, while others are installed in an open slot designed especially to accept modular voltage regulators. Some processors, such as Intel Haswell CPUs, feature voltage regulation components on the same package (or die) as the CPU, instead of having a VRM as part of the motherboard; such a design brings certain levels of simplification to complex voltage regulation involving numerous CPU supply voltages and dynamic powering up and down of various areas of a CPU. A voltage regulator integrated on-package or on-die is usually referred to as fully integrated voltage regulator (FIVR) or simply an integrated voltage regulator (IVR). Voltage regulator module (parts external to the processor's fully integrated voltage regulator) on a computer motherboard, covered with heat sinks Most modern CPUs require less than , Bob Dobkin, John Hamburger.
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A more common solution where good ripple rejection is required is to use a reservoir capacitor to reduce the ripple to something manageable and then pass the current through a voltage regulator circuit. The regulator circuit, as well as providing a stable output voltage, will incidentally filter out nearly all of the ripple as long as the minimum level of the ripple waveform does not go below the voltage being regulated to.Ryder pp 353-355 Switched-mode power supplies usually include a voltage regulator as part of the circuit. Voltage regulation is based on a different principle than filtering: it relies on the peak inverse voltage of a diode or series of diodes to set a maximum output voltage; it may also use one or more voltage amplification devices like transistors to boost voltage during sags.
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Series resistors may replace chokes for reducing the output DC voltage, and shunt resistors may be used for voltage regulation.
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Each additional stage of two diodes and two capacitors increases the output voltage by twice the peak AC supply voltage.
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The low-voltage network generally relies upon fuses or low-voltage circuit breakers to remove both overload and earth faults.
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On the busbar, the residual voltage can be measured with a set of voltage transformers in an open-delta connection.
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One is to reduce the operating voltage of the circuit, as in a dual-voltage CPU, or to reduce the voltage change involved in a state change (making a state change only, changing node voltage by a fraction of the supply voltage—low voltage differential signaling, for example). This approach is limited by thermal noise within the circuit. There is a characteristic voltage (proportional to the device temperature and to the Boltzmann constant), which the state switching voltage must exceed in order for the circuit to be resistant to noise. This is typically on the order of 50–100 mV, for devices rated to 100 degrees Celsius external temperature (about 4 kT, where T is the device's internal temperature in kelvins and k is the Boltzmann constant).
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Voltage optimisation is an electrical energy saving technique which is mainly installed in series with the mains electricity supply to provide a reduced supply voltage for the site's equipment. Typically, voltage optimisation can improve power quality by balancing phase voltages and filtering harmonics and transients from the supply, although not always. Voltage optimisers are essentially transformers used to deliver power at a reduced voltage from the raw mains supply. The term voltage optimisation is frequently misused, as the term implies some form of selective voltage reduction, which will improve the energy consumption within a building, whereas generally these units consists of a transformer within a box, offering no selectivity and dropping voltage on all supplies, whether this would offer a commercial benefit or not.
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An autotransformer with multiple taps may be applied to adjust the voltage at the end of a long distribution circuit to correct for excess voltage drop; when automatically controlled, this is one example of a voltage regulator.
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Ion transport takes place across any epithelium. Transport may be in either direction. Ion transport produces a potential difference (voltage difference) across the epithelium. The voltage is measured using two voltage electrodes placed near the tissue/epithelium.
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The undershoot phase occurs because unlike voltage-gated sodium channels, voltage-gated potassium channels inactivate much more slowly. Nevertheless, as more voltage-gated K+ channels become inactivated, the membrane potential recovers to its normal resting steady state..
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This is generally true for 12 volt systems, but becomes more ambiguous as the voltage increases to 100 volts. The meaning also varies when alternating current is used, as there is the more commonly known root mean square voltage (120 V) but also a peak wave voltage (170 V). Telephones for example use low voltage cabling, but the ringing voltage from the central office has an RMS voltage of 60-105V. Although low voltage cabling does not require inspection or training to install in some jurisdictions, it is still important for installers to be aware of specific safety rules such as how to correctly penetrate building fire barriers.
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To conserve power and manage heat, many laptop and desktop processors have a power management feature that software (usually the operating system) can use to adjust the clock speed and core voltage dynamically. Often a voltage regulator module converts from 5V or 12 V or some other voltage to whatever CPU core voltage is required by the CPU. The trend is towards lower core voltages, which conserve power. This presents the CMOS designer with a challenge, because in CMOS the voltages go only to ground and the supply voltage, the source, gate, and drain terminals of the FETs have only the supply voltage or zero voltage across them.
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The input voltage source has to have internal impedance Z_{int} > 0 or it has to be connected through another impedance element to the input. Under these conditions, the input voltage Vi of the circuit changes its polarity as the output voltage exceeds the voltage drop VZ across the impedance (Vi = Vz – Vo < 0). A typical application is a negative impedance converter with voltage inversion (VNIC). It is interesting that the circuit input voltage has the same polarity as the output voltage, although it is applied to the inverting op-amp input; the input source has an opposite polarity to both the circuit input and output voltages.
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An open-loop op-amp and comparator may be considered as an analog-digital device having analog inputs and a digital output that extracts the sign of the voltage difference between its two inputs.When the non-inverting (+) input is at a higher voltage than the inverting (−) input, the comparator output switches nearly to +VS, which is its high supply voltage. When the non-inverting (+) input is at a lower voltage than the inverting (−) input, the comparator output switches nearly to -VS, which is its low supply voltage. The positive feedback is applied by adding a part of the output voltage to the input voltage in series or parallel manner.
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Schematic of basic AC-to-DC power supply, showing (from L-R) transformer, full-wave bridge rectifier, filter capacitor and resistor load DC power supplies use AC mains electricity as an energy source. Such power supplies will employ a transformer to convert the input voltage to a higher or lower AC voltage. A rectifier is used to convert the transformer output voltage to a varying DC voltage, which in turn is passed through an electronic filter to convert it to an unregulated DC voltage. The filter removes most, but not all of the AC voltage variations; the remaining AC voltage is known as ripple.
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Voltage-gated ion channel. When the membrane is polarized, the voltage sensing domain of the channel shifts, opening the channel to ion flow (ions represented by yellow circles). Voltage-gated ion channels open and close in response to the electrical potential across the cell membrane. Portions of the channel domain act as voltage sensors.
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Practically, DVR systems can to inject up to 50% of nominal voltage, but only for a short time (up to 0.1 seconds). However, most voltage sags are much less than 50 percent, so this is not typically an issue. DVRs can also mitigate the damaging effects of voltage swells, voltage unbalance and other waveform distortions.
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The SSSC’s counterpart is the Dynamic Voltage Regulator (DVR). Although both are utilized for series voltage sag compensation, their operating principles differ from each other. The static synchronous series compensator injects a balance voltage in series with the transmission line. On the other hand, the DVR compensates the unbalance in supply voltage of different phases.
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Before solid state AC voltage regulation was available or cost effective, motor generator sets were used to provide a variable AC voltage. The DC voltage to the generators armature would be varied manually or electronically to control the output voltage. When used in this fashion, the MG set is equivalent to an isolated variable transformer.
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14 Figure 8. Dickson voltage doubler using diode-wired MOSFETs There are many variations and improvements to the basic Dickson charge pump. Many of these are concerned with reducing the effect of the transistor drain-source voltage. This can be very significant if the input voltage is small, such as a low-voltage battery.
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However, if the Thévenin source drives a unity gain buffer such as that in Figure 1 (top, with unity gain), the voltage input to the amplifier is VA, and with no voltage division because the amplifier input resistance is infinite. At the output the dependent voltage source delivers voltage Av VA = VA to the load, again without voltage division because the output resistance of the buffer is zero. A Thévenin equivalent circuit of the combined original Thévenin source and the buffer is an ideal voltage source VA with zero Thévenin resistance.
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For example, the Thévenin resistance of a combination of a voltage follower driven by a voltage source with high Thévenin resistance is reduced to only the output resistance of the voltage follower (a small resistance). That resistance reduction makes the combination a more ideal voltage source. Conversely, a voltage follower inserted between a small load resistance and a driving stage presents a large load to the driving stage—an advantage in coupling a voltage signal to a small load. This configuration is commonly used in the output stages of class-B and class-AB amplifiers.
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From that point on, the low impedance of the diode keeps the voltage across the diode at that value. center In this circuit, a typical voltage reference or regulator, an input voltage, Uin, is regulated down to a stable output voltage Uout. The breakdown voltage of diode D is stable over a wide current range and holds Uout approximately constant even though the input voltage may fluctuate over a wide range. Because of the low impedance of the diode when operated like this, resistor R is used to limit current through the circuit.
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For metallized film capacitors, the maximum possible pulse voltage is limited because of the limited current-carrying capacity between contact of the electrodes and the electrodes themselves. The rated pulse voltage Vp is the peak value of the pulse voltage which may be applied continuously to a capacitor at the rated temperature and at a given frequency. The pulse voltage capacity is given as pulse voltage rise time dV/dT in V/μs and also implies the maximum pulse current capacity. The values on the pulse rise time refer to the rated voltage.
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Reduced-voltage, star-delta or soft starters connect the motor to the power supply through a voltage reduction device and increases the applied voltage gradually or in steps. Two or more contactors may be used to provide reduced voltage starting of a motor. By using an autotransformer or a series inductance, a lower voltage is present at the motor terminals, reducing starting torque and inrush current. Once the motor has come up to some fraction of its full-load speed, the starter switches to full voltage at the motor terminals.
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Multimeter set to measure voltage Instruments for measuring voltages include the voltmeter, the potentiometer, and the oscilloscope. Analog voltmeters, such as moving-coil instruments, work by measuring the current through a fixed resistor, which, according to Ohm's Law, is proportional to the voltage across the resistor. The potentiometer works by balancing the unknown voltage against a known voltage in a bridge circuit. The cathode-ray oscilloscope works by amplifying the voltage and using it to deflect an electron beam from a straight path, so that the deflection of the beam is proportional to the voltage.
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They are implemented as a voltage follower with series negative feedback driven by a constant input voltage source (i.e., a negative feedback voltage stabilizer). The voltage follower is loaded by a constant (current sensing) resistor acting as a simple current-to-voltage converter connected in the feedback loop. The external load of this current source is connected somewhere in the path of the current supplying the current sensing resistor but out of the feedback loop.
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The channel is closed at the resting voltage level, but opens abruptly when the voltage exceeds a certain threshold, allowing a large influx of sodium ions that produces a very rapid change in the membrane potential. Recovery from an action potential is partly dependent on a type of voltage-gated potassium channel that is closed at the resting voltage level but opens as a consequence of the large voltage change produced during the action potential.
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Voltage optimisation is a term given to the systematic controlled reduction in the voltages received by an energy consumer to reduce energy use, power demand and reactive power demand. While some voltage 'optimisation' devices have a fixed voltage adjustment, others electronically regulate the voltage automatically. Voltage optimisation systems are typically installed in series with the mains electrical supply to a building, allowing all its electrical equipment to benefit from an optimised supply.
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If the Hall voltage is measured when no magnetic field is present, the output should be zero. However, if voltage at each output terminal is measured with respect to ground, a non-zero voltage will appear. This is the common mode voltage (CMV), and is the same at each output terminal. The output interface then converts the electrical signal from the Hall sensor; the Hall voltage: a signal that is significant to the application context.
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In some cases, several separate lamps are used with resistive voltage dividers arranged to allow additional lamps to strike as the applied voltage rises higher. The lamps are mounted in order from lowest voltage to highest, this minimal bar graph providing a crude indication of voltage. Incandescent bulbs may also be used in some electronic equipment repair, and a trained technician can usually tell the approximate voltage by using the brightness as a crude indicator.
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Other testers give only a simple on/off indication of a detected electric field. Professional-grade testers will also have a feature to reassure the user that the battery and lamp are working. Voltage detector pens are made for either line-voltage or lower-voltage (around 50 volt) ranges. A tester intended for mains-voltage detection may not provide any indication on lower-voltage control circuits such as those used for doorbells or HVAC control.
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Voltage is defined as a mapping from the set of edge pairs to real numbers, . Voltage is directly analogous to electrical voltage in an electrical network. The voltage in the forward and reverse directions between a pair of nodes are the additive inverses of one another: . The input voltage is the sum of the voltages over a set of edges, P_{ab}, that form a path between the s and t nodes.
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The manufacturer may specify the voltage drop across the fuse at rated current. There is a direct relationship between a fuse's cold resistance and its voltage drop value. Once current is applied, resistance and voltage drop of a fuse will constantly grow with the rise of its operating temperature until the fuse finally reaches thermal equilibrium. The voltage drop should be taken into account, particularly when using a fuse in low-voltage applications.
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Generic ladder filters with either (a) voltage input/voltage output, (b) current input/voltage output, (c) voltage input/current output or (d) current input/ current output. The output may also be the voltage across or the current through an internal component of the last element. The definition and synthesis of leapfrog filters is described by Temes & LaPatra, Sedra & Brackett, Chen and Wait, Huelsman & Korn. Synthesis of leapfrog filters typically includes the following steps: :1.
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High-voltage capacitors can benefit from a pre-charge to limit in-rush currents at power-up of high voltage direct current (HVDC) circuits. This will extend the life of the component and may mitigate high-voltage hazards.
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The base voltage might be the nominal voltage of a bus. Different types of quantities are labeled with the same symbol (pu); it should be clear whether the quantity is a voltage, current, or other unit of measurement.
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Microchip AN795 "Voltage to Frequency / Frequency to Voltage Converter" p. 4: "13-bit A/D converter" Carr, Joseph J. (1996) Elements of electronic instrumentation and measurement, Prentice Hall, p. 402, ."Voltage-to-Frequency Analog-to-Digital Converters". globalspec.
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The Lira–Gulu–Agago High Voltage Power Line is a planned high voltage power line in the Northern Region of Uganda.
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Active terminators consist of a voltage regulator that keeps the voltage used for the terminating resistor(s) at a constant level.
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Since this method measures the voltage across the battery, a constant-current (rather than a constant-voltage) charging circuit is used.
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The voltage source and the capacitor counteract each other, resulting in a net voltage of zero as seen by the load.
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Some chloride channels are activated only by voltage (i.e., voltage-gated), while others are activated by , other extracellular ligands, or pH.
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IGCT are available with or without reverse blocking capability. Reverse blocking capability adds to the forward voltage drop because of the need to have a long, low-doped P1 region. IGCTs capable of blocking reverse voltage are known as symmetrical IGCT, abbreviated S-IGCT. Usually, the reverse blocking voltage rating and forward blocking voltage rating are the same.
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These are voltage signals (as opposed to current signals) and it is the signal information (voltage) that is desired, not power to drive a transducer, such as a speaker or antenna. The actual information that is exchanged between the devices is the variance in voltage; it is this alternating voltage signal that conveys the information, making the current irrelevant.
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The Mbale–Bulambuli–Siti Medium Voltage Power Line is a medium voltage electricity power line (33kV), under construction, connecting the medium voltage substation at Siti II Hydroelectric Power Station in Bukwo District, in the Eastern Region of Uganda, to another medium voltage substation in the city of Mbale, the largest urban centre in Uganda's Eastern Region.
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Changing the DC voltage across the varactor changes its capacitance, which changes the resonant frequency of the tuned circuit. Voltage controlled relaxation oscillators can be constructed by charging and discharging the energy storage capacitor with a voltage controlled current source. Increasing the input voltage increases the rate of charging the capacitor, decreasing the time between switching events.
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In accelerator physics, the term acceleration voltage means the effective voltage surpassed by a charged particle along a defined straight line. If not specified further, the term is likely to refer to the longitudinal effective acceleration voltage V_\parallel. The acceleration voltage is an important quantity for the design of microwave cavities for particle accelerators. See also shunt impedance.
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Over-excitation is used to achieve a faster response time. It's when a coil momentarily receives a higher voltage than its nominal rating. To be effective the over excitation voltage must be significantly, but not to the point of diminishing returns, higher than the normal coil voltage. Three times the voltage typically gives around ⅓ faster response.
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Though the phase angles of voltage and current are rotated, the magnitudes of voltage and current remain constant along the length of the line. For load > SIL, the voltage will drop from sending end and the line will “consume” VARs. For load < SIL, the voltage will increase from sending end, and the line will “generate” VARs.
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The weighing curve of the CCIF 1951 Psophometric voltage is a circuit noise voltage measured with a psophometer that includes a CCIF-1951 weighting network. "Psophometric voltage" should not be confused with "psophometric emf," i.e., the emf in a generator or line with 600 Ω internal resistance. For practical purposes, the psophometric emf is twice the corresponding psophometric voltage.
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A 5651 voltage-regulator tube in operation In the mid-20th century, prior to the development of solid state components such as Zener diodes, voltage regulation in circuits was often accomplished with voltage-regulator tubes, which used glow discharge.
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A charge transfer switch OR CTS charge pump is a charge pump that offers better low-voltage performance and "a better voltage pumping gain and a higher output voltage" than previous charge pumps such as the Dickson charge pump.
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Valves are high voltage/low current devices in comparison with transistors. Tetrode and pentode valves have very flat anode current vs. anode voltage indicating high anode output impedances. Triodes show a stronger relationship between anode voltage and anode current.
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An individual PMC can be read by applying a small voltage across the cell. As long as the applied read voltage is less than both the programming and erasing voltage threshold, the direction of the bias is not significant.
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Galvanic skin potential (GSP) refers to the voltage measured between two electrodes without any externally applied current. It is measured by connecting the electrodes to a voltage amplifier. This voltage also varies with the emotional state of the subject.
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Voltage regulators are often used in lieu of passive voltage dividers when it is necessary to accommodate high or fluctuating load currents.
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A small differential input voltage signal gives rise, through multiple stages of current amplification, to a much larger voltage signal on output.
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A Voltage controller thyristor based dimmer rack An electrical schematic for a typical SCR-based light dimmer A voltage controller, also called an AC voltage controller or AC regulator is an electronic module based on either thyristors, TRIACs, SCRs or IGBTs, which converts a fixed voltage, fixed frequency alternating current (AC) electrical input supply to obtain variable voltage in output delivered to a resistive load. This varied voltage output is used for dimming street lights, varying heating temperatures in homes or industry, speed control of fans and winding machines and many other applications, in a similar fashion to an autotransformer. Voltage controller modules come under the purview of power electronics. Because they are low-maintenance and very efficient, voltage controllers have largely replaced such modules as magnetic amplifiers and saturable reactors in industrial use.
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1\. Label all nodes in the circuit. Arbitrarily select any node as reference. 2\. Define a voltage variable from every remaining node to the reference. These voltage variables must be defined as voltage rises with respect to the reference node. 3\.
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"Voltage" is an analog value. Therefore, during the digitization's second step, the voltage has to be transformed into a digital value by an A/D converter. Now the raw digital image is available. A microphone transforms the sound into a voltage.
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Action potentials are driven by channel proteins whose configuration switches between closed and open states as a function of the voltage difference between the interior and exterior of the cell. These voltage-sensitive proteins are known as voltage- gated ion channels.
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They generally carry voltages from 4.6 to 33 kilovolts (kV) for distances up to 30 miles, and include transformers to step the voltage down from the primary voltage to the lower secondary voltage used by the customer. A service drop carries this lower voltage to the customer's premises. Subtransmission lines carry higher voltage power from regional substations to local substations. They usually carry 46 kV, 69 kV, or 115 kV for distances up to 60 miles.
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Voltage regulator module for an IBM Netfinity 7000 M10 server running an Intel Xeon processor A voltage regulator module (VRM), sometimes called processor power module (PPM), is a buck converter that provides a microprocessor the appropriate supply voltage, converting or to a much lower voltage required by the CPU, allowing processors with different supply voltage to be mounted on the same motherboard. On personal computer (PC) systems, the VRM is typically made up of power MOSFET devices.
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A filter may be as simple as a single sufficiently large capacitor or choke, but most power-supply filters have multiple alternating series and shunt components. When the ripple voltage rises, reactive power is stored in the filter components, reducing the voltage; when the ripple voltage falls, reactive power is discharged from the filter components, raising the voltage. The final stage of rectification may consist of a zener diode-based voltage regulator, which almost completely eliminates any residual ripple.
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However, on some vehicles and scanners it will show up as "lambda" or "equivalence ratio." If the PID displays a voltage reading, it should be equal to the sensor's reference voltage when the air/fuel mixture is ideal. The reference voltage varies from car to car, but is often 3.3 V or 2.6 V. When the fuel mixture becomes richer (on a sudden, quick acceleration), the voltage should decrease. Under lean conditions (such as deceleration) the voltage should increase.
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But by slightly altering the voltage of the two plates, the electron's trajectory could be modified so that they would naturally travel towards the lower voltage side. The plates were connected to an oscillator that reversed the relative voltage of the two plates at a given frequency. At any given instant, the electron will naturally be pushed towards the lower-voltage side of the tube. The electron will then oscillate back and forth as the voltage changes.
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Ohm's law and Kirchhoff's circuit laws are used to calculate the appropriate resistor value, by subtracting the LED voltage drop from the supply voltage and dividing by the desired operating current. With a sufficiently high supply voltage, multiple LEDs in series can be powered with one resistor. If the supply voltage is close or equal to the LED forward voltage, then no reasonable value for the resistor can be calculated, so some other method of current limiting is used.
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The voltage versus current characteristics of an LED are similar to any diode. Current is approximately an exponential function of voltage according to the Shockley diode equation, and a small voltage change may result in a large change in current. If the voltage is below or equal to the threshold no current flows and the result is an unlit LED. If the voltage is too high, the current will exceed the maximum rating, overheating and potentially destroying the LED.
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For example, a higher-voltage distribution level circuit may feed several lower-voltage distribution circuits through transformers. If the higher voltage circuit is de-energized, but if lower- voltage circuits connected remain energized, the higher voltage circuit will remain energized. Another problem can arise when de-energized wires become energized through electrostatic or electromagnetic induction from energized wires nearby. All live line work PPE must be kept clean from contaminants and regularly tested for di-electric integrity.
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During the first negative phase of the AC input voltage, the capacitor in a positive clamper circuit charges rapidly. As Vin becomes positive, the capacitor serves as a voltage doubler; since it has stored the equivalent of Vin during the negative cycle, it provides nearly that voltage during the positive cycle. This essentially doubles the voltage seen by the load. As Vin becomes negative, the capacitor acts as a battery of the same voltage of Vin.
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185 This voltage "doubler" will only succeed in raising the output voltage by about to . If the drop across the final smoothing transistor is also taken into account the circuit may not be able to increase the voltage at all without using multiple stages. A typical Schottky diode, on the other hand, might have an on state voltage of . A doubler using this Schottky diode will result in a voltage of , or at the output after the smoothing diode, .
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The capacitor in the L-C low-pass filter therefore charges up to the peak voltage of the secondary of the transformer. This peak voltage is generally considerably higher than the average voltage of the secondary of the transformer. The higher voltage which occurs across the capacitor, and therefore also at the output of the power supply, can damage components within the power supply. The higher voltage can also damage any remaining electrical loads connected to the power supply.
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An AC power supply typically takes the voltage from a wall outlet (mains supply) and uses a transformer to step up or step down the voltage to the desired voltage. Some filtering may take place as well. In some cases, the source voltage is the same as the output voltage; this is called an isolation transformer. Other AC power supply transformers do not provide mains isolation; these are called autotransformers; a variable output autotransformer is known as a variac.
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For example, if the terminal voltage of the VSC is higher than the AC voltage at the point of connection, the STATCOM generates reactive current; conversely, when the amplitude of the voltage source is lower than the AC voltage, it absorbs reactive power. The response time of a STATCOM is shorter than that of a static VAR compensator (SVC), mainly due to the fast switching times provided by the IGBTs of the voltage source converter. The STATCOM also provides better reactive power support at low AC voltages than an SVC, since the reactive power from a STATCOM decreases linearly with the AC voltage (as the current can be maintained at the rated value even down to low AC voltage).
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In higher power transmitters powered by AC, a transformer steps the input voltage up to the high voltage needed. The sinusoidal voltage from the transformer is applied directly to the capacitor, so the voltage on the capacitor varies from a high positive voltage, to zero, to a high negative voltage. The spark gap is adjusted so sparks only occur near the maximum voltage, at peaks of the AC sine wave, when the capacitor was fully charged. Since the AC sine wave has two peaks per cycle, ideally two sparks occurred during each cycle, so the spark rate was equal to twice the frequency of the AC power (often multiple sparks occurred during the peak of each half cycle).
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These characteristics are also known as I–V curves, referring to the standard symbols for current and voltage. In electronic components with more than two terminals, such as vacuum tubes and transistors, the current-voltage relationship at one pair of terminals may depend on the current or voltage on a third terminal. This is usually displayed on a more complex current–voltage graph with multiple curves, each one representing the current-voltage relationship at a different value of current or voltage on the third terminal. For example the diagram at right shows a family of I–V curves for a MOSFET as a function of drain voltage with overvoltage (VGS − Vth) as a parameter.
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Cockcroft-Walton voltage doubler circuit. It generates a DC output voltage Vo of twice the peak-to-peak AC input voltage Vi A voltage doubler uses two stages to approximately double the DC voltage that would have been obtained from a single-stage rectifier. An example of a voltage doubler is found in the input stage of switch mode power supplies containing a SPDT switch to select either 120 V or 240 V supply. In the 120 V position the input is typically configured as a full-wave voltage doubler by opening one AC connection point of a bridge rectifier, and connecting the input to the junction of two series-connected filter capacitors.
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However, diodes can have more complicated behavior than this simple on–off action, because of their nonlinear current-voltage characteristics. Semiconductor diodes begin conducting electricity only if a certain threshold voltage or cut-in voltage is present in the forward direction (a state in which the diode is said to be forward-biased). The voltage drop across a forward-biased diode varies only a little with the current, and is a function of temperature; this effect can be used as a temperature sensor or as a voltage reference. Also, diodes' high resistance to current flowing in the reverse direction suddenly drops to a low resistance when the reverse voltage across the diode reaches a value called the breakdown voltage.
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Electric utilities aim to provide service to customers at a specific voltage level, for example, 220 V or 240 V. However, due to Kirchhoff's Laws, the voltage magnitude and thus the service voltage to customers will in fact vary along the length of a conductor such as a distribution feeder (see Electric power distribution). Depending on law and local practice, actual service voltage within a tolerance band such as ±5% or ±10% may be considered acceptable. In order to maintain voltage within tolerance under changing load conditions, various types of devices are traditionally employed: • a load tap changer (LTC) at the substation transformer, which changes the turns ratio in response to load current and thereby adjusts the voltage supplied at the sending end of the feeder; • voltage regulators, which are essentially transformers with tap changers to adjust the voltage along the feeder, so as to compensate for the voltage drop over distance; and • capacitors, which reduce the voltage drop along the feeder by reducing current flow to loads consuming reactive power. A new generation of devices for voltage regulation based on solid-state technology are in the early commercialization stages.
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Thus the output modifies the input voltage by means of parallel positive feedback and does not affect the threshold (the base-emitter voltage).
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Like other electrolytic capacitors, niobium electrolytic capacitors are polarized and require the anode electrode voltage to be positive relative to the cathode voltage.
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In the simplest case a common collector amplifier also known as emitter follower is used with the base of the regulating transistor connected directly to the voltage reference: center A simple transistor regulator will provide a relatively constant output voltage Uout for changes in the voltage Uin of the power source and for changes in load RL, provided that Uin exceeds Uout by a sufficient margin and that the power handling capacity of the transistor is not exceeded. The output voltage of the stabilizer is equal to the Zener diode voltage minus the base–emitter voltage of the transistor, UZ − UBE, where UBE is usually about 0.7 V for a silicon transistor, depending on the load current. If the output voltage drops for any external reason, such as an increase in the current drawn by the load (causing a decrease in the collector–emitter voltage to observe KVL), the transistor's base–emitter voltage (UBE) increases, turning the transistor on further and delivering more current to increase the load voltage again. Rv provides a bias current for both the Zener diode and the transistor.
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A linear direct current regulated supply will maintain the output voltage unless the brownout is severe and the input voltage drops below the drop out voltage for the regulator, at which point the output voltage will fall and high levels of ripple from the rectifier/reservoir capacitor will appear on the output. A switched-mode power supply which has a regulated output will be affected. As the input voltage falls, the current draw will increase to maintain the same output voltage and current, until such a point that the power supply malfunctions. Brownouts can cause unexpected behaviour in systems with digital control circuits.
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Volt-VAR Control or VVC refers to the process of managing voltage levels and reactive power (VAR) throughout the power distribution systems. These two quantities are related, because as reactive power flows over an inductive line (and all lines have some inductance) that line sees a voltage drop. VVC encompasses devices that purposely inject reactive power into the grid to alter the size of that voltage drop, in addition to equipment that more directly controls voltage. In the legacy grid, there are three primary tools for carrying out voltage management: Load Tap Changers (LTCs), voltage regulators, and capacitor banks.
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In a grid containing many distributed generators subject to disconnection at under voltage, it is possible to cause a chain reaction that takes other generators offline as well. This can occur in the event of a voltage dip that causes one of the generators to disconnect from the grid. As voltage dips are often caused by too little generation for the load in a distribution grid, removing generation can cause the voltage to drop further. This may bring the voltage down enough to cause another generator to trip, lower the voltage even further, and may cause a cascading failure.
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Photomultiplier tubes typically utilize 1000 to 2000 volts to accelerate electrons within the chain of dynodes. (See Figure near top of article.) The most negative voltage is connected to the cathode, and the most positive voltage is connected to the anode. Negative high-voltage supplies (with the positive terminal grounded) are often preferred, because this configuration enables the photocurrent to be measured at the low voltage side of the circuit for amplification by subsequent electronic circuits operating at low voltage. However, with the photocathode at high voltage, leakage currents sometimes result in unwanted "dark current" pulses that may affect the operation.
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Over time, the rate of change of current decreases, and the voltage across the inductor also then decreases, increasing the voltage at the load. During this time, the inductor stores energy in the form of a magnetic field. If the switch is opened while the current is still changing, then there will always be a voltage drop across the inductor, so the net voltage at the load will always be less than the input voltage source. When the switch is opened again (off-state), the voltage source will be removed from the circuit, and the current will decrease.
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Simulation result for formation of inversion channel (electron density) and attainment of threshold voltage (IV) in a nanowire MOSFET. Note that the threshold voltage for this device lies around 0.45 V. The threshold voltage, commonly abbreviated as Vth, of a field-effect transistor (FET) is the minimum gate-to-source voltage VGS (th) that is needed to create a conducting path between the source and drain terminals. It is an important scaling factor to maintain power efficiency. When referring to a junction field-effect transistor (JFET), the threshold voltage is often called "pinch-off voltage" instead.
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Voltage dividers can be used to allow a microcontroller to measure the resistance of a sensor. The sensor is wired in series with a known resistance to form a voltage divider and a known voltage is applied across the divider. The microcontroller's analog-to-digital converter is connected to the center tap of the divider so that it can measure the tap voltage and, by using the measured voltage and the known resistance and voltage, compute the sensor resistance. An example that is commonly used involves a potentiometer (variable resistor) as one of the resistive elements.
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The ferroresonant action is a flux limiter rather than a voltage regulator, but with a fixed supply frequency it can maintain an almost constant average output voltage even as the input voltage varies widely. The ferroresonant transformers, which are also known as Constant Voltage Transformers (CVTs) or ferros, are also good surge suppressors, as they provide high isolation and inherent short-circuit protection. A ferroresonant transformer can operate with an input voltage range ±40% or more of the nominal voltage. Output power factor remains in the range of 0.96 or higher from half to full load.
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Striking usually occurs in three phases. In the triggering phase, an extremely high voltage pulse from the "series triggering" transformer creates a spark streamer between the electrodes, but the impedance is too high for the main voltage to take over. A "boost voltage" phase is then initiated, where a voltage that is higher than the voltage drop between the electrodes is driven through the lamp, until the gas is heated to a plasma state. When impedance becomes low enough, the "current control" phase takes over, where as the main voltage begins to drive the current to a stable level.
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Working on high voltage power lines Specifying a voltage measurement requires explicit or implicit specification of the points across which the voltage is measured. When using a voltmeter to measure potential difference, one electrical lead of the voltmeter must be connected to the first point, one to the second point. A common use of the term "voltage" is in describing the voltage dropped across an electrical device (such as a resistor). The voltage drop across the device can be understood as the difference between measurements at each terminal of the device with respect to a common reference point (or ground).
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By placing a suitable load resistance in the anode circuit, the varying current will cause a varying voltage across the resistance which can be much larger than the input voltage variations, resulting in voltage gain. The triode is a normally "on" device; and current flows to the anode with zero voltage on the grid. The anode current is progressively reduced as the grid is made more negative relative to the cathode. Usually a constant DC voltage ("bias") is applied to the grid to set the DC current through the tube, and the varying signal voltage is superimposed on it.
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SSRs are characterised by a number of parameters including the required activating input voltage, current, output voltage and current, whether it is AC or DC, voltage drop or resistance affecting output current, thermal resistance, and thermal and electrical parameters for safe operating area (e.g., derating according to thermal resistance when repeatedly switching large currents). SSRs can also include zero crossing hardware to only turn the voltage on or off when the AC voltage is at zero. Proportional SSRs can delay the onset of voltage after the zero crossing in order to lower the current output (phase angle control).
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Current in the field windings of a shunt-wound generator is (approximately) independent of the load current, because currents in parallel branches are independent of each other. Since field current, and therefore field strength, is little affected by load current, the output voltage remains more nearly constant than does the output voltage of a series-wound generator. There will be a small armature voltage drop on load, which will be reflected in the voltage applied to the shunt field. The output voltage in a DC shunt-wound generator drops slightly as load current increases because of the voltage drop across the armature resistance.
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The power produced cannot, as earlier mentioned, be directly delivered to the grid without conversion. This is done in several steps; firstly the voltage is rectified from each generator. Then they are interconnected in parallel and the DC voltage is filtered (the filter consist of capacitors). The filter smooths out the voltage from the generators and creates a stable DC voltage.
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A static var compensator can also be used for voltage stability. However, a STATCOM has better characteristics than an SVC. When the system voltage drops sufficiently to force the STATCOM output current to its ceiling, its maximum reactive output current will not be affected by the voltage magnitude. Therefore, it exhibits constant current characteristics when the voltage is low under the limit.
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The Hoima–Kinyara–Kafu High Voltage Power Line is a planned high voltage electricity power line, connecting the high voltage substation at Kabaale, Buseruka sub-county, Hoima District, in the Western Region of Uganda to another high voltage substation at Kafu, Nakasongola District, in the Central Region of Uganda. On the way, the power line passes through Kinyara Sugar Works, in Masindi District.
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For direct current and relatively low frequencies, a voltage divider may be sufficiently accurate if made only of resistors; where frequency response over a wide range is required (such as in an oscilloscope probe), a voltage divider may have capacitive elements added to compensate load capacitance. In electric power transmission, a capacitive voltage divider is used for measurement of high voltage.
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Also, the open circuit voltage (i.e. the voltage between the electrodes when the dielectric is not yet broken) can be identified as steady state voltage of the RC circuit. In generators based on transistor control, the user is usually able to deliver a train of pulses of voltage to the electrodes. Each pulse can be controlled in shape, for instance, quasi- rectangular.
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The influx of sodium ions causes an increase in voltage. If the voltage increases past a certain threshold, the sodium current activates other voltage-gated sodium channels transmitting a current along the dendrite. Dendritic spikes can be generated through both sodium and calcium voltage- gated channels. Dendritic spikes usually transmit signals at a much slower rate than axonal action potentials.
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GTO thyristors are available with or without reverse blocking capability. Reverse blocking capability adds to the forward voltage drop because of the need to have a long, low doped P1 region. GTO thyristors capable of blocking reverse voltage are known as Symmetrical GTO thyristors, abbreviated S-GTO. Usually, the reverse blocking voltage rating and forward blocking voltage rating are the same.
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These worked somewhat similarly to neon bulbs, the tube would not conduct until the cathode to anode voltage reached a breakdown voltage. The advantage of the thyratron was that the breakdown voltage could be controlled by the voltage on the grid. This allowed the frequency of the oscillation to be changed electronically. Thyratron oscillators were used as time bases in oscilloscopes.
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An integrated circuit voltage regulator A voltage regulator is a system designed to automatically maintain a constant voltage level. A voltage regulator may use a simple feed-forward design or may include negative feedback. It may use an electromechanical mechanism, or electronic components. Depending on the design, it may be used to regulate one or more AC or DC voltages.
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Nkenda is a power hub in Western Uganda. The Uganda Electricity Transmission Company Limited (UETCL), maintains a high-voltage substation at this location. The 220kV Nkenda–Fort Portal–Hoima High Voltage Power Line originates here, and so does the proposed 220kV Nkenda–Mpondwe–Beni High Voltage Power Line. This location is also the terminus of the 132kV Mbarara–Nkenda High Voltage Power Line.
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The power is the product of voltage and current and therefore also depends on the load. Over a certain voltage the current of the solar cell quickly drops to zero, as the graph illustrates. However, the batteries have a fairly constant voltage, which also has a rather different value than that of the solar cells. So a voltage transformation is needed.
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Voltage droop is the intentional loss in output voltage from a device as it drives a load. Adding droop in a voltage regulation circuit increases the headroom for load transients. All electrical systems have some amount of resistance between the regulator output and the load. At high currents, even a small resistance results in substantial voltage drop between the regulator and the load.
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Figure 5. Switched capacitor voltage doubler achieved by simply switching charged capacitors from parallel to series It is possible to use the simple diode-capacitor circuits described above to double the voltage of a DC source by preceding the voltage doubler with a chopper circuit. In effect, this converts the DC to AC before application to the voltage doubler.McComb, pp.
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High voltages may lead to electrical breakdown, resulting in an electrical discharge as illustrated by the plasma filaments streaming from a Tesla coil. High voltage electricity refers to electric potential large enough to cause injury or damage. In certain industries, high voltage refers to voltage above a certain threshold. Equipment and conductors that carry high voltage warrant special safety requirements and procedures.
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English-language power engineering students are advised to remember: "ELI the ICE man" or "ELI on ICE" – the voltage E, leads the current I, in an inductor L. The current I leads the voltage E in a capacitor C. Another common mnemonic is "CIVIL" – in a capacitor (C) the current (I) leads voltage (V), voltage (V) leads current (I) in an inductor (L).
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The term "constant voltage" in MPP tracking is used to describe different techniques by different authors, one in which the output voltage is regulated to a constant value under all conditions and one in which the output voltage is regulated based on a constant ratio to the measured open circuit voltage (V_{OC}). The latter technique is referred to in contrast as the "open voltage" method by some authors. If the output voltage is held constant, there is no attempt to track the maximum power point, so it is not a maximum power point tracking technique in a strict sense, though it does have some advantages in cases when the MPP tracking tends to fail, and thus it is sometimes used to supplement an MPPT method. In the "constant voltage" MPPT method (also known as the "open voltage method"), the power delivered to the load is momentarily interrupted and the open-circuit voltage with zero current is measured.
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The active components in equivalent circuit are voltage/current sources. They are usually at least two sources, which could be variety options depending on the analysis approach, such as two voltage sources, two current sources, and one voltage and one current source.
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In electronics, the cut-off voltage is the voltage at which a battery is considered fully discharged, beyond which further discharge could cause harm. Some electronic devices, such as cell phones, will automatically shut down when the cut-off voltage has been reached.
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Conversely, deactivation of the voltage sensor takes place at hyperpolarized potentials, when the membrane collects more negative charge on the inner leaflet. Activation of the voltage sensor increases the activity of the phosphatase domain, while deactivation of the voltage sensor decreases phosphatase activity.
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For powering low voltage circuits, there is a static converter that converts an input voltage of 550 volts to 28 volts. The low-voltage power circuits use two 12-volt batteries. It is also possible to install traction batteries for stand-alone travel.
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A surface DC voltmeter is an instrument that measures voltage with no electric charge transfer. It can accurately measure surface potential (voltage) on materials without making physical contact and so there is no electrostatic charge transfer or loading of the voltage source.
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At a later date, Uganda Electricity Transmission Company Limited (UETCL) plans to develop the 132kV Mbale–Bulambuli High Voltage Power Line, at which time the 33kV medium voltage line will plug into the high voltage line, for better stability of the network.
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R3 and R4 then act as a voltage divider that makes Q1's base voltage negative and consequently turns off Q1. Q1's collector current will be essentially zero, so R2 will pull the output voltage Q high (logic 1; near V+).
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The voltage reduction capacitor must withstand the full mains voltage, and it must also have enough capacitance to support maximum load current at the rated output voltage. Taken together, these constraints limit practical uses of this type of supply to low-power applications.
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High Voltage Hot Rod Show is a WiiWare game developed by High Voltage Software. It was released in North America on January 19, 2009.
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This is accomplished by applying long polarizing currents to the nerve and measuring the influence of voltage on voltage gated-ion channels beneath myelin.
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The voltage dependence of Kv4.2 block varies among the three different heteropodatoxins. It is less voltage dependent for HpTx1 than for HpTx2 or HpTx3 .
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Battery simulator AC input voltage requirement is typically universal voltage (85-135 or 180-250 VAC), and the frequency is 50 or 60 Hz.
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Measured device capacitance across an EDLC's operating voltage Device parameters such as capacitance initial resistance and steady state resistance are not constant, but are variable and dependent on the device's operating voltage. Device capacitance will have a measurable increase as the operating voltage increases. For example: a 100F device can be seen to vary 26% from its maximum capacitance over its entire operational voltage range. Similar dependence on operating voltage is seen in steady state resistance (Rss) and initial resistance (Ri).
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The lines on the left of each gate represent input wires or ports. The value of the input is represented by a voltage on the lead. For so-called "active-high" logic, 0 is represented by a voltage close to zero or "ground", while 1 is represented by a voltage close to the supply voltage; active-low reverses this. The line on the right of each gate represents the output port, which normally follows the same voltage conventions as the input ports.
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Consumer loads expect voltage within a certain range, and the regulators require it be within a certain percent of the nominal voltage (for example, in the US it is 土5%). Reactive power can be used to compensate the voltage drops, but must be provided closer to the loads than real power needs (this is because reactive power tend to travel badly through the grid). Notice that voltage can be controlled also using transformer taps and voltage regulators.Ahmadimanesh, A., and M. Kalantar.
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The common collector arrangement applies the input voltage between base and collector, and to take the output voltage between emitter and collector. This causes negative feedback, and the output voltage tends to follow the input voltage. This arrangement is also used as the input presents a high impedance and does not load the signal source, though the voltage amplification is less than one. The common-collector circuit is, therefore, better known as an emitter follower, source follower, or cathode follower.
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In these applications, the output voltage Vo is inserted with an opposite polarity in respect to the input voltage Vi travelling along the loop (but in respect to ground, the polarities are the same). As a result, the effective voltage across, and the current through, the impedance decrease; the input impedance increases. Increased impedance is implemented by a non- inverting amplifier with gain of 0 < Av < 1\. The (magnitude of) output voltage is less than the input voltage Vi and partially neutralizes it.
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These act as very high speed switches, momentarily limiting the peak voltage across their terminals. By design, MOV surge limiters are selected to trigger at a voltage somewhat above the local mains supply voltage, so that they do not clip normal voltage peaks, but clip abnormal higher voltages. In the US, this is (nominally) 120 VAC. It should be borne in mind that this voltage specification is RMS, not peak, and also that it is only a nominal (approximate) value.
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Any semiconductor diode has an exponential voltage/current characteristic that gives an effective "knee" voltage sometimes used as a voltage reference. This voltage ranges from 0.3 V for germanium diodes up to about 3 volts for certain light emitting diodes. These devices have a strong temperature dependence, which may make them useful for temperature measurement or for compensating bias in analog circuits. Zener diodes are also frequently used to provide a reference voltage of moderate stability and accuracy, useful for many electronic devices.
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If the input current is increased, then the collector voltage falls below the base voltage, and the Schottky diode starts to conduct and shunt some of the base drive current into the collector. The transistor is designed so that its collector saturation voltage () is less than the base–emitter voltage (roughly 0.6 V) minus the Schottky diode's forward voltage drop (roughly 0.2 V). Consequently, the excess input current is shunted away from the base and the transistor never goes into saturation.
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A closed- loop regulated joule thief When a more constant output voltage is desired, the joule thief can be given a closed-loop control. In the example circuit, the Schottky diode D1 blocks the charge built up on capacitor C1 from flowing back to the switching transistor Q1 when it is turned on. A 5.6 Volt Zener diode D2 and transistor Q2 forms the feedback control: when the voltage across the capacitor C1 is higher than the threshold voltage formed by Zener voltage of D2 plus the base-emitter turn-on voltage of transistor Q2, transistor Q2 is turned on diverting the base current of the switching transistor Q1, impeding the oscillation and prevents the voltage across capacitor C1 from rising even further. When the voltage across C1 drops below the threshold voltage Q2 turns off, allowing the oscillation to happen again.
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Many simple DC power supplies regulate the voltage using either series or shunt regulators, but most apply a voltage reference using a shunt regulator such as a Zener diode, avalanche breakdown diode, or voltage regulator tube. Each of these devices begins conducting at a specified voltage and will conduct as much current as required to hold its terminal voltage to that specified voltage by diverting excess current from a non-ideal power source to ground, often through a relatively low-value resistor to dissipate the excess energy. The power supply is designed to only supply a maximum amount of current that is within the safe operating capability of the shunt regulating device. If the stabilizer must provide more power, the shunt regulator output is only used to provide the standard voltage reference for the electronic device, known as the voltage stabilizer.
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However, as the bias voltage continues to increase, the p-n junction breaks down when the electric field strength across the p-n junction reaches a critical level. As this electric field is induced by the bias voltage over the junction it is denoted as the breakdown voltage, VBD. A SPAD is reverse biased with an excess bias voltage, Vex, above the breakdown voltage, but below a second, higher breakdown voltage associated with the SPAD's guard ring. The total bias (VBD+Vex) therefore exceeds the breakdown voltage to such a degree that “At this bias, the electric field is so high [higher than 3×105 V/cm] that a single charge carrier injected into the depletion layer can trigger a self-sustaining avalanche.
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An exploded electrolytic capacitor on a PCB Electrolytic capacitors are polarized capacitors and generally require an anode electrode voltage to be positive relative to the cathode voltage. However, the cathode foil of aluminum electrolytic capacitors is provided with a very thin, natural air- originated oxide layer. This oxide layer has a voltage proof of approximately 1 to 1.5 V. Therefore, aluminum electrolytic capacitors with non-solid electrolyte can continuously withstand a very small reverse voltage and, for example, can be measured with an AC voltage of about 0.5 V, as specified in relevant standards. At a reverse voltage lower than −1.5 V at room temperature, the cathode aluminum foil begins to build up an oxide layer corresponding to the applied voltage.
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Die of the LM1117 low-dropout (LDO) linear voltage regulator. Die of the LM2940L regulator A low-dropout or LDO regulator is a DC linear voltage regulator that can regulate the output voltage even when the supply voltage is very close to the output voltage. The advantages of a low dropout voltage regulator over other DC to DC regulators include the absence of switching noise (as no switching takes place), smaller device size (as neither large inductors nor transformers are needed), and greater design simplicity (usually consists of a reference, an amplifier, and a pass element). The disadvantage is that, unlike switching regulators, linear DC regulators must dissipate power, and thus heat, across the regulation device in order to regulate the output voltage.
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The above peak voltage is only achieved in coils in which air discharges do not occur; in coils which produce sparks, like entertainment coils, the peak voltage on the terminal is limited to the voltage at which the air breaks down and becomes conductive. As the output voltage increases during each voltage pulse, it reaches the point where the air next to the high voltage terminal ionizes and corona, brush discharges and streamer arcs, break out from the terminal. This happens when the electric field strength exceeds the dielectric strength of the air, about 30 kV per centimeter. Since the electric field is greatest at sharp points and edges, air discharges start at these points on the high voltage terminal.
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The current-voltage curve of a CDW solid therefore shows a very high electrical resistance up to the depinning voltage, above which it shows a nearly ohmic behavior. Under the depinning voltage (which depends on the purity of the material), the crystal is an insulator.
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If the nominal impedance is 4 ohms, the voltage would be 2 volts. If the nominal impedance is 8Ω, the voltage would be 2.83 volts.
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In differential mode, the emitter voltage is fixed (equal to the instant common input voltage); there is no negative feedback and the gain is maximum.
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A Zener diode can be applied in a voltage regulator circuit to regulate the voltage applied to a load, such as in a linear regulator.
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The dual track was reinstated in 1947. The voltage was increased to 1,500 V DC in conjunction with the voltage upgrade on the Keishin line.
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A bandgap voltage reference is a temperature independent voltage reference circuit widely used in integrated circuits. It produces a fixed (constant) voltage regardless of power supply variations, temperature changes and circuit loading from a device. It commonly has an output voltage around 1.25V (close to the theoretical band gap of silicon at 0K). This circuit concept was first published by David Hilbiber in 1964.
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In more modern designs, the rectifier is replaced by a voltage multiplier. Color television sets also have to use a regulator to control the high voltage. The earliest sets used a shunt vacuum tube regulator, but the introduction of solid state sets employed a simpler voltage dependent resistor. The rectified voltage is then used to supply the final anode of the cathode ray tube.
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In a PV module under operation, the extreme conditions are open-circuit and short-circuit. At open-circuit, the voltage is maximum (open-circuit voltage VOC) and the current zero. Whereas at short-circuit the current is maximum (short-circuit current, ISC) and the voltage zero. The power is given by the product of current and voltage and has a maximum at maximum power point (MPP).
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Piezoelectric direct discharge can be considered as a special technical realization of the dielectric barrier discharge, which combines the alternating current high voltage generator, high voltage electrode and the dielectric barrier into a single element. Namely, the high voltage is generated with a piezo-transformer, the secondary circuit of which acts also as the high voltage electrode.M. Teschke and J. Engemann, Contrib. Plasma Phys.
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The "low" voltage level is zero to 0.8 volts, and the "high" voltage level is 2 volts to 5 volts. A differential TTL signal consists of two such wires, also referenced to a system ground. The logic level on one wire is always the complement of the other. The principle is similar to that of low-voltage differential signaling (LVDS), but with different voltage levels.
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The secondary is usually grounded on one terminal. There are three primary types of voltage transformers (VT): electromagnetic, capacitor, and optical. The electromagnetic voltage transformer is a wire-wound transformer. The capacitor voltage transformer uses a capacitance potential divider and is used at higher voltages due to a lower cost than an electromagnetic VT. An optical voltage transformer exploits the electrical properties of optical materials.
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The base resistor RB is obligatory to prevent the impact of the input voltage through Q1 base-emitter junction on the emitter voltage. Direct-coupled circuit. To simplify the circuit, the R1-R2 voltage divider can be omitted connecting Q1 collector directly to Q2 base. The base resistor RB can be omitted as well so that the input voltage source drives directly Q1's base.
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Gas filled tubes and neon lamps have also been used as voltage references, primarily in tube-based equipment, as the voltage needed to sustain the gas discharge is comparatively constant. For example, the popular RCA 991RCA 991 Voltage Regulator tube data sheet "Voltage regulator tube" is an NE-16 neon lamp which fires at 87 volts and then holds 48-67 volts across the discharge path.
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DC to AC converters produce an AC output waveform from a DC source. Applications include adjustable speed drives (ASD), uninterruptible power supplies (UPS), Flexible AC transmission systems (FACTS), voltage compensators, and photovoltaic inverters. Topologies for these converters can be separated into two distinct categories: voltage source inverters and current source inverters. Voltage source inverters (VSIs) are named so because the independently controlled output is a voltage waveform.
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Figure 8: The AC input for an ASD. FIGURE 9: Single-Phase Half-Bridge Voltage Source Inverter The single-phase voltage source half-bridge inverters, are meant for lower voltage applications and are commonly used in power supplies. Figure 9 shows the circuit schematic of this inverter. Low-order current harmonics get injected back to the source voltage by the operation of the inverter.
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The voltage on the high voltage terminal cannot increase above the air breakdown voltage, because additional electric charge pumped into the terminal from the secondary winding just escapes into the air. The output voltage of open-air Tesla coils is limited to a few million volts by air breakdown, but higher voltages can be achieved by coils immersed in pressurized tanks of insulating oil.
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Intuitively, this can be understood as follows, for a variable capacitor-based amplifier. Charge Q in a capacitor obeys: :Q = C \times V therefore the voltage across is :V = Q/C. Knowing the above, if a capacitor is charged until its voltage equals the sampled voltage of an incoming weak signal, and if the capacitor's capacitance is then reduced (say, by manually moving the plates further apart), then the voltage across the capacitor will increase. In this way, the voltage of the weak signal is amplified.
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The voltages between the three phases are the same in magnitude, however the voltage magnitudes between a particular phase and the neutral vary. The phase-to-neutral voltage of two of the phases will be half of the phase-to-phase voltage. The remaining phase-to-neutral voltage will be /2 the phase-to-phase voltage. So if A-B, B-C and C-A are all 240 volts, then A-N and C-N will both be 120 volts, but B-N will be 208 volts.
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The conceptual model of the buck converter is best understood in terms of the relation between current and voltage of the inductor. Beginning with the switch open (off-state), the current in the circuit is zero. When the switch is first closed (on-state), the current will begin to increase, and the inductor will produce an opposing voltage across its terminals in response to the changing current. This voltage drop counteracts the voltage of the source and therefore reduces the net voltage across the load.
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Voltage protection circuits protect circuitry from either overvoltage or undervoltage; either of these situations can have detrimental effects. Supervisory circuits that specifically focus on voltage regulation are often sold as supply voltage supervisors and will reset the protected circuit when the voltage returns to operating range. Two types of overvoltage protection devices are currently used: clamping, which passes through voltages up to a certain level, and foldback, which shunts voltage away from the load. The shunting creates a short circuit which removes power from the protected circuitry.
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Electric field (arrows) and contours of constant voltage created by a pair of oppositely charged objects. The electric field is at right angles to the voltage contours, and the field is strongest where the spacing between contours is the smallest. Voltage, which is synonymous with difference in electrical potential, is the ability to drive an electric current across a resistance. Indeed, the simplest definition of a voltage is given by Ohm's law: V=IR, where V is voltage, I is current and R is resistance.
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The output voltage of a tripler is in practice below three times the peak input voltage due to their high impedance, caused in part by the fact that as each capacitor in the chain supplies power to the next, it partially discharges, losing voltage doing so. Triplers were commonly used in color television receivers to provide the high voltage for the cathode ray tube (CRT, picture tube). Triplers are still used in high voltage supplies such as copiers, laser printers, bug zappers and electroshock weapons.
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The process has four levels of interconnect. While the P55C remained compatible with Socket 7, the voltage requirements for powering the chip differ from the standard Socket 7 specifications. Most motherboards manufactured for Socket 7 prior to the establishment of the P55C standard are not compliant with the dual voltage rail required for proper operation of this CPU (2.9 volt core voltage, 3.3 volt I/O voltage). Intel addressed the issue with OverDrive upgrade kits that featured an interposer with its own voltage regulation.
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This mode is used in differential switches and ECL gates. Breakdown. If the input voltage continues increasing and exceeds the base- emitter breakdown voltage, the base-emitter junction of the transistor driven by the lower input voltage breaks down. If the input sources are low resistive, an unlimited current will flow directly through the "diode bridge" between the two input sources and will damage them. In common mode, the emitter voltage follows the input voltage variations; there is a full negative feedback and the gain is minimum.
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The voltage between A and C is the sum of the voltage between A and B and the voltage between B and C. The various voltages in a circuit can be computed using Kirchhoff's circuit laws. When talking about alternating current (AC) there is a difference between instantaneous voltage and average voltage. Instantaneous voltages can be added for direct current (DC) and AC, but average voltages can be meaningfully added only when they apply to signals that all have the same frequency and phase.
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This inverted voltage profile may confuse conventional controls. In one such scenario, load tap changers expecting voltage to decrease with distance from the substation may choose an operating point that in fact causes voltage down the line to exceed operating limits. Comparison of 24-hour voltage swings on a feeder with no PV, 20% PV and 20% PV with volt-VAR control. The voltage regulation issues caused by DG at the distribution level are complicated by lack of utility monitoring equipment along distribution feeders.
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A real rectifier characteristically drops part of the input voltage (a voltage drop, for silicon devices, of typically 0.7 volts plus an equivalent resistance, in general non-linear)—and at high frequencies, distorts waveforms in other ways. Unlike an ideal rectifier, it dissipates some power. An aspect of most rectification is a loss from the peak input voltage to the peak output voltage, caused by the built-in voltage drop across the diodes (around 0.7 V for ordinary silicon p–n junction diodes and 0.3 V for Schottky diodes). Half- wave rectification and full-wave rectification using a center-tapped secondary produces a peak voltage loss of one diode drop.
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The difference between the non-inverting input voltage and the inverting input voltage is amplified by the op-amp. This connection forces the op-amp to adjust its output voltage simply equal to the input voltage (Vout follows Vin so the circuit is named op-amp voltage follower). The impedance of this circuit does not come from any change in voltage, but from the input and output impedances of the op-amp. The input impedance of the op-amp is very high (1 MΩ to 10 TΩ), meaning that the input of the op-amp does not load down the source and draws only minimal current from it.
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In batteries, the cut-off (final) voltage is the prescribed lower-limit voltage at which battery discharge is considered complete. The cut-off voltage is usually chosen so that the maximum useful capacity of the battery is achieved. The cut-off voltage is different from one battery to the other and it is highly dependent on the type of battery and the kind of service in which the battery is used. When testing the capacity of a NiMH or NiCd battery a cut-off voltage of 1.0 V per cell is normally used, whereas 0.9 V is normally used as the cut-off voltage of an alkaline cell.
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As a prerequisite to the success of these efforts, power grid interconnections between the member countries need to be established. Such interconnections include the interconnection between Ethiopia and Kenya via the Sodo–Moyale–Suswa High Voltage Power Line Other such linkages are the Bujagali–Tororo–Lessos High Voltage Power Line, between Uganda and Kenya, the Isinya–Singida High Voltage Power Line, between Kenya and Tanzania, the Kawanda–Birembo High Voltage Power Line, between Uganda and Rwanda, the Nkenda–Mpondwe–Beni High Voltage Power Line, between Uganda and the Democratic Republic of the Congo. and the Karuma–Juba High Voltage Power Line between Uganda and South Sudan.
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In local sense, the supply simply measures the voltage at its output terminals, where the leads to the load connect. This method has the problem of not accounting for the voltage drop due to resistance of the leads, which is proportional to the amount of current drawn by the load. That is, the supply might be producing the correct voltage at its output terminals, but there will be a lower voltage at the input terminals of the load. When this might cause a problem, remote sense can be used to force the power supply to counteract the voltage drop by raising the voltage at its output terminals.
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In a circuit known as a chopper, the average voltage applied to the motor is varied by switching the supply voltage very rapidly. As the "on" to "off" ratio is varied to alter the average applied voltage, the speed of the motor varies. The percentage "on" time multiplied by the supply voltage gives the average voltage applied to the motor. Therefore, with a 100 V supply and a 25% "on" time, the average voltage at the motor will be 25 V. During the "off" time, the armature's inductance causes the current to continue through a diode called a "flyback diode", in parallel with the motor.
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A basic voltage clamp will iteratively measure the membrane potential, and then change the membrane potential (voltage) to a desired value by adding the necessary current. This "clamps" the cell membrane at a desired constant voltage, allowing the voltage clamp to record what currents are delivered. Because the currents applied to the cell must be equal to (and opposite in charge to) the current going across the cell membrane at the set voltage, the recorded currents indicate how the cell reacts to changes in membrane potential. Cell membranes of excitable cells contain many different kinds of ion channels, some of which are voltage-gated.
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Setting this equal to zero yields: dI/dV = -I(V)/V. Therefore, the maximum power point is achieved when the incremental conductance is equal to the negative of the instantaneous conductance. The characteristic of the power-voltage curve also shows that: when the voltage is smaller than the maximum power point, dP/dV > 0 , so dI/dV > -I/V ; when the voltage is bigger than the maximum power point, dP/dV < 0 or dI/dV < -I/V . Thus, the MPP tracker can know where it is on the power-voltage curve by calculating the relation of the change of current/voltage and the current voltage themselves.
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The choice of was related to the efficiency of power transmission as a function of voltage and cost, not based on a neat and tidy ratio of the supply voltage. For a given power level, a higher voltage allows for a lower current and usually better efficiency at the greater cost for high-voltage equipment. It was found that was an optimal point, where a higher voltage would still improve efficiency but not by a significant amount in relation to the higher costs incurred by the need for larger insulators and greater clearance from structures. To avoid short circuits, the high voltage must be protected from moisture.
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It is equal to the difference in voltage between the object and a point some distance away. The touch voltage could be nearly the full voltage across the grounded object if that object is grounded at a point remote from the place where the person is in contact with it. For example, a crane that was grounded to the system neutral and that contacted an energized line would expose any person in contact with the crane or its uninsulated load line to a touch voltage nearly equal to the full fault voltage. "Mesh voltage" is a factor calculated when a grid of grounding conductors is installed.
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Voltage-gated hydrogen channel 1 is a protein that in humans is encoded by the HVCN1 gene. Voltage-gated hydrogen channel 1 is a voltage-gated proton channel that has been shown to allow proton transport into phagosomes and out of many types of cells including spermatozoa, electrically excitable cells and respiratory epithelial cells. The proton-conducting HVCN1 channel has only transmembrane domains corresponding to the S1-S4 voltage sensing domains (VSD) of voltage-gated potassium channels and voltage-gated sodium channels. Molecular simulation is consistent with a water-filled pore that can function as a "water wire" for allowing hydrogen bonded H+ to cross the membrane.
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A group of small molecule inhibitors of the Hv1 channel are shown as chemotherapeutics and anti-inflammatory agents. When activated, the voltage-gated proton channel HV1 can allow up to 100,000 hydrogen ions across the membrane each second. Whereas most voltage-gated ion channels contain a central pore that is surrounding by alpha helices and the voltage-sensing domain (VSD), voltage-gated hydrogen channels contain no central pore, so their voltage-sensing regions (VSD) carry out the job of bringing acidic protons across the membrane. As mentioned, these voltage-gated hydrogen channels only carry outward current, meaning they are used to move acidic protons out of the membrane.
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The electric field strength (in volts per meter) at which breakdown occurs is an intrinsic property of the insulating material called its dielectric strength. The electric field is usually caused by a voltage difference applied across the material. The applied voltage required to cause breakdown in a given insulating object is called the object's breakdown voltage. The electric field created in a given insulating object by an applied voltage varies depending on the size and shape of the object and the location on the object where the voltage is applied, so in addition to the material's dielectric strength, the breakdown voltage depends on these factors.
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BB20004 contributed however a big part to the realisation of the BB25500 and later dual-voltage locomotives and expanded the knowledge of dual-voltage locomotives greatly.
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There is also a trade-off between voltage rating and "on" resistance, so high- voltage FETs have a relatively high "on" resistance and hence conduction losses.
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This voltage drives electricity in a wire. This becomes electrical power, the reverse of most phenomena that use a voltage to put a particle in motion.
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These mass-resolved beams are directed into a detector where it is converted into voltage. The voltage detected is then used to calculate the isotopic ratio.
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Differential input voltage (the voltage between two inputs) of a modern rail-to-rail comparator is usually limited only by the full swing of power supply.
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Since a battery charger is intended to be connected to a battery, it may not have voltage regulation or filtering of the DC voltage output; it is cheaper to make them that way. Battery chargers equipped with both voltage regulation and filtering are sometimes termed battery eliminators.
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In many high voltage applications, the corona is an unwanted side effect. Corona discharge from high voltage electric power transmission lines constitutes an economically significant waste of energy. Corona discharges are suppressed by improved insulation, corona rings, and making high voltage electrodes in smooth rounded shapes.
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The increase of resistance generates a voltage pulse. The magnitude of the voltage pulse is a function of the volume of the particle. The duration of the pulse is related to the transit time of the inclusion. The voltage pulses are amplified and their amplitude measured digitally.
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Sometimes, special circuits are built for the purpose of sensing and controlling the temperature or voltage status. Devices such as thermistors, voltage dependent resistors, thermostats and sensors such as infrared thermometers are used to modify the current upon different conditions such as circuit-temperature and input voltage.
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International Standard IEC 60038, IEC standard voltages, defines a set of standard voltages for use in low voltage and high voltage AC and DC electricity supply systems.
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GTx1-15 is a toxin from the Chilean tarantula venom that acts as both a voltage-gated calcium channel blocker and a voltage-gated sodium channel blocker.
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Because an AC waveform has a voltage peak that is higher than the average value produced by the rectifier, the same set operating on the same root mean square AC supply voltage would have a higher effective voltage after the rectifier stage. In areas using 110–120 volt AC, a simple half-wave rectifier limited the maximum plate voltage that could be developed; this was adequate for relatively low-power audio equipment, but television receivers or higher-powered amplifiers required either a more complex voltage doubler rectifier or warranted the use of a power transformer with a conveniently high secondary voltage. Areas with 220–240 volt AC supplies could develop higher plate voltage with a simple rectifier. Transformerless power supplies were feasible for television receivers in 220–240 volt areas.
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In contrast to frequency, voltage varies widely throughout electric systems, because it is the voltage difference between two devices that largely determines the direction and magnitude of the current (hence the power) that flows between them. Therefore voltage is a more local phenomenon, and grid- friendly devices that respond to voltage will support more local aspects of the electric delivery system.Voltage Level as Information Carrier in Smart Distribution Networks However, load types such as thermally protected induction motors and power electronics can respond poorly to significant voltage changes.Chen, Heng.
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The grading ring surrounds the end of the insulator next to the high voltage conductor. It reduces the gradient at the end, resulting in a more even voltage gradient along the insulator, allowing a shorter, cheaper insulator to be used for a given voltage. Grading rings also reduce aging and deterioration of the insulator that can occur at the high voltage end due to the high electric field there. In very high voltage apparatus like Marx generators and particle accelerator tubes, insulating columns often have many metal grading rings spaced evenly along their length.
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To maintain the voltage at the customer's service within the acceptable range, electrical distribution utilities use regulating equipment at electrical substations or along the distribution line. At a substation, the step-down transformer will have an automatic on-load tap changer, allowing the ratio between transmission voltage and distribution voltage to be adjusted in steps. For long (several kilometres) rural distribution circuits, automatic voltage regulators may be mounted on poles of the distribution line. These are autotransformers, again, with on-load tapchangers to adjust the ratio depending on the observed voltage changes.
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The telephone company maintains large battery systems that supply DC line voltage for the operation of analog telephone service at customer locations. The voltage supplied is a compromise between operational needs for reliable service and safety precautions for customers and service personnel. The length of the line to a customer telephone interface presents a resistance across which the central office voltage experiences a drop and therefore the voltage at the customer site may vary. The nominal battery (system) voltage is 52.1 V, based on a 24-cell lead-acid battery.
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UL 1449 became compliance mandatory in jurisdictions that adopted the NEC with the 3rd edition in September 2009 to increase safety compared to products conforming to the 2nd edition. A measured limiting voltage test, using six times higher current (and energy), defines a voltage protection rating (VPR). For a specific protector, this voltage may be higher compared to a Suppressed Voltage Ratings (SVR) in previous editions that measured let-through voltage with less current. Due to non-linear characteristics of protectors, let-through voltages defined by 2nd edition and 3rd edition testing are not comparable.
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If a voltage source such as a battery is placed in an electrical circuit, the higher the voltage of the source the greater the amount of current that it will drive across the available resistance. The functional significance of voltage lies only in potential differences between two points in a circuit. The idea of a voltage at a single point is meaningless. It is conventional in electronics to assign a voltage of zero to some arbitrarily chosen element of the circuit, and then assign voltages for other elements measured relative to that zero point.
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The current–voltage characteristics of four devices: a resistor with large resistance, a resistor with small resistance, a P–N junction diode, and a battery with nonzero internal resistance. The horizontal axis represents the voltage drop, the vertical axis the current. All four plots use the passive sign convention. A current–voltage characteristic or I–V curve (current–voltage curve) is a relationship, typically represented as a chart or graph, between the electric current through a circuit, device, or material, and the corresponding voltage, or potential difference across it.
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Schematic of an audio-frequency voltage-controlled oscillator A voltage-controlled capacitor is one method of making an LC oscillator vary its frequency in response to a control voltage. Any reverse-biased semiconductor diode displays a measure of voltage-dependent capacitance and can be used to change the frequency of an oscillator by varying a control voltage applied to the diode. Special-purpose variable-capacitance varactor diodes are available with well-characterized wide-ranging values of capacitance. A varactor is used to change the capacitance (and hence the frequency) of an LC tank.
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Due to the limits of oxide growth, there is a limit on the maximum voltage rating of tantalum oxide for each of the presently available tantalum powders (see Figure 3). The dielectric layer thickness generated by the forming voltage is directly proportional to the voltage proof of electrolytic capacitors.K. H. Thiesbürger: Der Elektrolyt-Kondensator. 4. Auflage. Roederstein, Landshut 1991, OCLC 313492506 Electrolytic capacitors are manufactured with a safety margin in oxide layer thickness, which is the ratio between voltage used for electrolytical creation of dielectric and rated voltage of the capacitor, to ensure reliable functionality.
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Mercury batteries using a mercury(II) oxide cathode have a very flat discharge curve, holding constant 1.35 V (open circuit) voltage until about the last 5% of their lifetime, when their voltage drops rapidly. The voltage remains within 1% for several years at light load, and over a wide temperature range, making mercury batteries useful as a voltage reference in electronic instruments and in photographic light meters. Mercury batteries with cathodes made of a mix of mercuric oxide and manganese dioxide have output voltage of 1.4 V and a more sloped discharge curve.
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The high output impedance of tube plate circuits is not well matched to low-impedance loads such as loudspeakers or antennas. A matching network is required for efficient power transfer; this may be a transformer at audio frequencies, or various tuned networks at radio frequencies. In a cathode follower or common-plate configuration, the output is taken from the cathode resistance. Because of negative feedback (the cathode-ground voltage cancels the grid-ground voltage) the voltage gain is close to unity and the output voltage follows the grid voltage.
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Dual-voltage CPUs were introduced for performance gain when increasing clock speeds and finer semiconductor fabrication processes caused excess heat generation and power supply concerns, especially regarding laptop computers. Using a voltage regulator, the external I/O voltage levels was transformed to lower voltages to reduce power draw, resulting in less heat for the ability to operate at higher frequencies. VRT is a feature on older Intel P5 Pentium processors that are typically intended for use in a mobile environment. It refers to splitting the core voltage supply from the I/O voltage.
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Internal structure Application An error amplifier is most commonly encountered in feedback unidirectional voltage control circuits, where the sampled output voltage of the circuit under control, is fed back and compared to a stable reference voltage. Any difference between the two generates a compensating error voltage which tends to move the output voltage towards the design specification. An error amplifier is essentially what its name says, that is, it amplifies an error signal. This error is based on the difference between a reference signal and the input signal.
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A voltage reference is an electronic device that ideally produces a fixed (constant) voltage irrespective of the loading on the device, power supply variations, temperature changes, and the passage of time. Voltage references are used in power supplies, analog-to-digital converters, digital-to-analog converters, and other measurement and control systems. Voltage references vary widely in performance; a regulator for a computer power supply may only hold its value to within a few percent of the nominal value, whereas laboratory voltage standards have precisions and stability measured in parts per million.
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Potassium voltage-gated channel subfamily H member 1 is a protein that in humans is encoded by the KCNH1 gene. Voltage-gated potassium (Kv) channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. This gene encodes a member of the potassium channel, voltage- gated, subfamily H. This member is a pore-forming (alpha) subunit of a voltage-gated non-inactivating delayed rectifier potassium channel.
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When the cell is less hyperpolarized, the magnesium leaves the channel more often and stays away for longer (on average). Hence, the magnesium blockade of the open NMDAR channel is membrane voltage-dependent. While the NMDAR channel itself displays little or no voltage dependence (its open channel I/V curve is more or less linear), the voltage dependence of the magnesium block effectively, if indirectly, confers voltage dependence to this channel. Thus, in effect, the NMDAR channel is both a ligand-gated and voltage-gated channel at the same time.
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Electrical apparatus that interrupts high-voltage circuits is designed to safely direct the resulting arc so that it dissipates without damage. High voltage circuit breakers often use a blast of high pressure air, a special dielectric gas (such as SF6 under pressure), or immersion in mineral oil to quench the arc when the high voltage circuit is broken. Wiring in equipment such as X-ray machines and lasers requires care. The high voltage section is kept physically distant from the low voltage side to reduce the possibility of an arc forming between the two.
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The accelerating voltage may be chosen between 30 and 200 kV. Usually it is about 60 or 150 kV, depending on various conditions. With rising voltage the technical problems and the price of the equipment rapidly increase, hence, whenever it is possible a lower voltage of about 60 kV is to be chosen. The maximum power of the high voltage supply depends on the maximum depth of weld required.
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The DC supply provides twice the normal voltage the anode sees. The regulator can allow none or all of the voltage to pass, or any intermediate value. The audio input operates the regulator in such a way as to produce the instantaneous anode voltage needed to reproduce the modulation envelope. An advantage of the series regulator is that it can set the anode voltage to any desired value.
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In DC circuits and pulsed circuits, current and voltage reversal are affected by the damping of the system. Voltage reversal is encountered in RLC circuits that are underdamped. The current and voltage reverse direction, forming a harmonic oscillator between the inductance and capacitance. The current and voltage tends to oscillate and may reverse direction several times, with each peak being lower than the previous, until the system reaches an equilibrium.
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V-curve of a synchronous machine By varying the excitation of a synchronous motor, it can be made to operate at lagging, leading and unity power factor. Excitation at which the power factor is unity is termed normal excitation voltage. The magnitude of current at this excitation is minimum. Excitation voltage more than normal excitation is called over excitation voltage, excitation voltage less than normal excitation is called under excitation.
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This analog switch uses a four-terminal simple MOSFET of either P or N type. In the case of an n-type switch, the body is connected to the most negative supply (usually GND) and the gate is used as the switch control. Whenever the gate voltage exceeds the source voltage by at least a threshold voltage, the MOSFET conducts. The higher the voltage, the more the MOSFET can conduct.
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A known current is passed down the connection and the voltage that develops is measured. From the voltage and current the resistance of the connection can be calculated and compared to the expected value. There are two common ways to test for a short: # A low voltage test. A low power, low voltage source is connected between two conductors that should not be connected and the amount of current is measured.
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SIDAC. Idealized breakover diode voltage and current relationships. Once the voltage exceeds the turn-on threshold, the device turns on and the voltage rapidly falls while the current increases. A silicon diode for alternating current (SIDAC) is a less commonly used device, electrically similar to the DIAC, but having, in general, a higher breakover voltage and greater current handling capacity. The SIDAC is another member of the thyristor family.
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A microwave (12–18GHz) voltage-controlled oscillator A voltage-controlled oscillator (VCO) is an electronic oscillator whose oscillation frequency is controlled by a voltage input. The applied input voltage determines the instantaneous oscillation frequency. Consequently, a VCO can be used for frequency modulation (FM) or phase modulation (PM) by applying a modulating signal to the control input. A VCO is also an integral part of a phase-locked loop.
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Kampa BM, Letzkus JJ, Stuart GJ. 2006. Requirement of dendritic calcium spikes for induction of spike-timing- dependent synaptic plasticity. Journal of Physiology 574.1:283-290 T-type and R-type channels are all part of the alpha 1 subunit class of calcium channels. The various types of voltage-gated calcium channels result in two forms of voltage activation: low-voltage-activated (LVA) and high-voltage-activated (HVA) calcium currents.
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A drawback of the voltage mode operation is that the stress on switch transistors is high during the cross over time, when both the voltage and current are high. This drawback is alleviated by using current mode operation. This is achieved by inserting an inductor in the transformer center tap supply. This inductor drops the center tap voltage down when the dI/dt would be very high in voltage mode.
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W.L. Everitt, p. 434 The allowable peak 100% modulated input signal voltage is limited to the magnitude of the bias voltage, corresponding to an unmodulated carrier peak voltage of half the bias voltage magnitude. Either fixed bias or cathode bias may be used for the plate detector. When cathode bias is implemented, a capacitor of low impedance at the carrier frequency and high impedance at audio frequencies bypasses the cathode resistor.
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This limits the current that can flow from Q to ground. The PMOS transistor's channel is in a low resistance state and much more current can flow from the supply to the output. Because the resistance between the supply voltage and Q is low, the voltage drop between the supply voltage and Q due to a current drawn from Q is small. The output, therefore, registers a high voltage.
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The circuit works by alternately switching the output of each stage between a voltage doubler driven by \phi_1 and one driven by \phi_2. This behaviour leads to another advantage over the Dickson multiplier: reduced ripple voltage at double the frequency. The increase in ripple frequency is advantageous because it is easier to remove by filtering. Each stage (in an ideal circuit) raises the output voltage by the peak clock voltage.
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The value of current drawn is to be set by the input voltage vIN. Here the sink is to be analyzed by idealizing the op amp as a nullor. Using properties of the input nullator portion of the nullor, the input voltage across the op amp input terminals is zero. Consequently, the voltage across reference resistor RR is the applied voltage vIN, making the current in RR simply vIN/RR.
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Capacitance–voltage profiling (or C–V profiling, sometimes CV profiling) is a technique for characterizing semiconductor materials and devices. The applied voltage is varied, and the capacitance is measured and plotted as a function of voltage. The technique uses a metal–semiconductor junction (Schottky barrier) or a p–n junctionJ. Hilibrand and R.D. Gold, "Determination of the Impurity Distribution in Junction Diodes From Capacitance-Voltage Measurements", RCA Review, vol.
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Halogen lamps are manufactured with enough halogen to match the rate of tungsten evaporation at their design voltage. Increasing the applied voltage increases the rate of evaporation, so at some point there may be insufficient halogen and the lamp goes black. Over- voltage operation is not generally recommended. With a reduced voltage the evaporation is lower and there may be too much halogen, which can lead to abnormal failure.
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With a resistive or other load in the plate circuit, the varying current will result in a varying voltage at the plate. With proper biasing, this voltage will be an amplified (but inverted) version of the AC voltage applied to the control grid, thus the tetrode can provide voltage gain. In the tetrode, the function of the other grid varies according to the type of tetrode; this is discussed below.
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A Ward Leonard Control system with generator and motor connected directly. The speed of a DC motor is controlled by varying the voltage fed to the generator field windings, Vgf, which varies the output voltage of the generator. The varied output voltage will change the voltage of the motor, since they are connected directly through the armature. Consequently, changing the Vgf will control the speed of the motor.
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Schematic of LM317 in a typical voltage regulator configuration, including decoupling capacitors to address input noise and output transients. The LM317 has three pins: INput, OUTput, and ADJustment. Internally the device has a bandgap voltage reference which produces a stable reference voltage of Vref= 1.25 V followed by a feedback-stabilized amplifier with a relatively high output current capacity. How the adjustment pin is connected determines the output voltage as follows.
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Voltage-gated sodium channels are responsible for the fast action potentials involved in nerve conduction. Slower action potentials in muscle cells and some types of neurons are generated by voltage-gated calcium channels. Each of these types comes in multiple variants, with different voltage sensitivity and different temporal dynamics. The most intensively studied type of voltage-dependent ion channels comprises the sodium channels involved in fast nerve conduction.
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There are multiple useful ways to define voltage, including the standard definition mentioned at the start of this page. There are also other useful definitions of work per charge (see this section). Voltage is defined so that negatively charged objects are pulled towards higher voltages, while positively charged objects are pulled towards lower voltages. Therefore, the conventional current in a wire or resistor always flows from higher voltage to lower voltage.
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Voltage controllers are only used under certain conditions:Bellman, Wilard F. (2001). LIGHTING THE STAGE: Art and Practice, Third Edition, Chapter 4 -The Control Console, Broadway Press, Inc., Louisville Kentucky, A winder being used in the construction of a transformer. #There has to be a load for a voltage controller to function: Since voltage controllers use thyristors for varying voltage, they need some kind of resistive load at the end to function.
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Equipment with high- powered motors or internal transformers designed to operate at 60 Hz may overheat at 50 Hz even if the voltage supplied is correct. Most mains-powered electrical equipment, though it may specify a single nominal voltage, actually has a range of tolerance above and below that point. Thus, devices usually can be used on either any voltage from approx. 100 to 120 V, or any voltage from approx.
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Every inline series-connected ammeter, including a multimeter in a current range, has a certain resistance. Most multimeters inherently measure voltage, and pass a current to be measured through a shunt resistance, measuring the voltage developed across it. The voltage drop is known as the burden voltage, specified in volts per ampere. The value can change depending on the range the meter sets, since different ranges usually use different shunt resistors.
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Electric systems use fewer components and are simpler to install and commission than hydronic systems. Some electric systems use line voltage technology while others use low voltage technology. The power consumption of an electric system is not based on voltage but rather wattage output produced by the heating element.
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The structure of a TPC1 ortholog from Arabidopsis thaliana has been solved by two laboratories. The structures were solved using X-ray crystallography and contained the fold of a voltage-gated ion channel and EF hands. Only a single voltage sensor domain appears to responsible for voltage sensing.
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CFE holds a monopoly on electricity transmission and distribution in the country. CFE operates the national transmission grid, composed of of high voltage lines, of medium voltage lines, and of low voltage distribution lines, through one of its departments, the Centro Nacional de Control de la Energía (CENACE).
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A magnetically-controlled shunt reactor (MCSR, CSR) represents electrotechnical equipment purposed for compensation of reactive power and stabilization of voltage level in high voltage (HV) electric networks rated for voltage classes 36 – 750 kV. MCSR is shunt-type static device with smooth regulation by means of inductive reactance.
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Voltage dividers are used for adjusting the level of a signal, for bias of active devices in amplifiers, and for measurement of voltages. A Wheatstone bridge and a multimeter both include voltage dividers. A potentiometer is used as a variable voltage divider in the volume control of many radios.
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The PT is typically described by its voltage ratio from primary to secondary. A 600:120 PT will provide an output voltage of 120 volts when 600 volts are impressed across its primary winding. Standard secondary voltage ratings are 120 volts and 70 volts, compatible with standard measuring instruments.
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As already stated, film thickness and throwpower are dependent on the application voltage. However, at excessively high voltages, a phenomenon called "rupture" can occur. The voltage where this phenomenon occurs is called the "rupture voltage". The result of rupture is a film that is usually very thick and porous.
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Because the T-type channels are voltage dependent, hyperpolarization of the cell past its inactivation voltage will close the channels throughout the SA node, and allow for another depolarizing event to occur. The voltage dependency of the T-type channel contributes to the rhythmic beating of the heart.
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Now the capacitor discharges towards -Vsat. At some point, the voltage at b becomes less than -β Vsat. The voltage at the non-inverting terminal will be greater than the voltage at the inverting terminal of the op-amp. So, the output of the op-amp is +Vsat.
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These bleeders discharge the focus supply, but not the high voltage final anode feed. The CRT itself forms a capacitor that can hold a sizable (and very dangerous) high voltage charge, so it is always advisable to momentarily ground a CRT's high voltage terminal before working on the unit.
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Power mode rejection ratio (PMRR) is a term used in electronics and defines how much noise or voltage variations in the power supply will affect the output signal(s). This also relates to series resistors for zener diode voltage references that is affected by input voltage and temperature.
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The voltage activated potassium channel (Kv) is regulated by PA. Its midpoint of activation shifts +50 mV upon PA hydrolysis, near resting membrane potentials. This suggests Kv could be opened by lipid hydrolysis independent of voltage and may qualify this channel as dual lipid and voltage gated channel.
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It is possible to completely remove the framework of high voltage compartment. Locomotive's roof is divided into several parts and over the high voltage compartment it is removable.
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It was launched with the Viking Dynamic Simulator. SPHINX stood for Space Plasma High Voltage Interaction Experiment. It was designed to test high-voltage equipment in outer space.
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ArcLight is a genetically-encoded voltage indicator (GEVI) created from Ciona intestinalis voltage sensor and the fluorescent protein super ecliptic pHluorin that carries a critical point mutation (A227D).
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Depending on the design, changing the autotransformer tap can cause a very brief output power disruption, which may cause UPSs equipped with a power-loss alarm to "chirp" for a moment. This has become popular even in the cheapest UPSs because it takes advantage of components already included. The main 50/60 Hz transformer used to convert between line voltage and battery voltage needs to provide two slightly different turns ratios: One to convert the battery output voltage (typically a multiple of 12 V) to line voltage, and a second one to convert the line voltage to a slightly higher battery charging voltage (such as a multiple of 14 V). The difference between the two voltages is because charging a battery requires a delta voltage (up to 13–14 V for charging a 12 V battery). Furthermore, it is easier to do the switching on the line-voltage side of the transformer because of the lower currents on that side.
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When newer CPUs required higher currents, switching mode voltage regulators like buck converters replaced linear regulators for efficiency. Since the first revision of the ATX standard, PSUs were required to have a 3.3 V output voltage rail. Rarely, a linear regulator generated these 3.3 V, supplied from the 5 V and converting the product of voltage drop and current to heat. In the most common design this voltage is generated by shifting and transforming the pulses of the 5 V rail on an additional choke, causing the voltage to rise delayed and rectified separately into a dedicated 3.3 V rail and getting the rising idle voltage cut by a device type TL431,ti.
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It is also possible to put the rectified waveform into a choke-input filter. The advantage of this circuit is that the current waveform is smoother: current is drawn over the entire cycle, instead of being drawn in pulses at the peaks of AC voltage each half-cycle as in a capacitor input filter. The disadvantage is that the voltage output is much lower – the average of an AC half-cycle rather than the peak; this is about 90% of the RMS voltage versus \sqrt 2 times the RMS voltage (unloaded) for a capacitor input filter. Offsetting this is superior voltage regulation and higher available current, which reduce peak voltage and ripple current demands on power supply components.
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Motor performance depends on three elements such as voltage across terminals, resistance across terminals, and magnetic force. These are influenced directly by such factors as voltage and type of power supply, number of turns per winding slot and diameter of magnetic wire, environmental temperature, type of magnet, flux yoke and phase. If only the voltage of the power supply changes, the change in motor performance is in direct proportion to that change in voltage. Unlike the constant-voltage power supply, the power supply with resistance will have a voltage drop due to its internal resistance, causing the stall current and, therefore, the stall torque to drop with the speed line bottomed to the left.
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DVRs may provide good solutions for end-users subject to unwanted power quality disturbances. However, they are generally not used in systems that are subject to prolonged reactive power deficiencies (resulting in low voltage conditions) and in systems that are vulnerable to voltage collapse. Because DVRs will maintain appropriate supply voltage, in such systems where incipient voltage conditions are present they actually make collapses more difficult to prevent and can even lead to cascading interruptions. Therefore, when applying DVRs, it is vital to consider the nature of the load whose voltage supply is being secured, as well as the transmission system which must tolerate the change in voltage-response of the load.
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The maximum collector-to-emitter voltage for the 2N3055, like other transistors, depends on the resistance path the external circuit provides between the base and emitter of the transistor; with 100 ohms a 70 volt breakdown rating, VCER, and the Collector-Emitter Sustaining voltage, VCEO(sus), is given by ON Semiconductor. Sometimes the 100 VCBO breakdown voltage (the maximum voltage between collector and base, with the emitter open, an unrealistic arrangement in practical circuits) is given as the only voltage rating, which can cause confusion. Manufacturers rarely specify the VCES voltage rating for the 2N3055. The total power dissipation (written PD in most American datasheets, Ptot in European ones) depends on the heatsink to which the 2N3055 is connected.
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These include the mobility of charge carriers, the optical absorption profile and general energetic driving forces that lead to a more efficient extraction of charge carriers The open circuit voltage (Voc) is the voltage when there is no current running through the device. This corresponds to the x-intercept on a current-voltage curve. Within bulk heterojunction organic photovoltaic devices, this value is highly dependent on HOMO and LUMO energy levels and work functions for the active layer materials Since power is the product of voltage and current, the maximum power point occurs when the product between voltage and current is maximized. The fill factor, FF, can be thought of as the “squareness” of a current voltage curve.
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The voltage can be smoothly varied between turns as the brush has a relatively high resistance (compared with a metal contact) and the actual output voltage is a function of the relative area of brush in contact with adjacent windings. The relatively high resistance of the brush also prevents it from acting as a short circuited turn when it contacts two adjacent turns. Typically the primary connection connects to only a part of the winding allowing the output voltage to be varied smoothly from zero to above the input voltage and thus allowing the device to be used for testing electrical equipment at the limits of its specified voltage range. The output voltage adjustment can be manual or automatic.
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By using a voltage source and resistor, the clamper can be biased to bind the output voltage to a different value. The voltage supplied to the potentiometer will be equal to the offset from zero (assuming an ideal diode) in the case of either a positive or negative clamper (the clamper type will determine the direction of the offset). If a negative voltage is supplied to either positive or negative, the waveform will cross the x-axis and be bound to a value of this magnitude on the opposite side. Zener diodes can also be used in place of a voltage source and potentiometer, hence setting the offset at the Zener voltage.
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The rated voltage includes a safety margin against the electrolyte's breakdown voltage at which the electrolyte decomposes. The breakdown voltage decomposes the separating solvent molecules in the Helmholtz double-layer, f. e. water splits into hydrogen and oxygen. The solvent molecules then cannot separate the electrical charges from each other.
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The slope is usually expressed as percentage change of counts per 100 V. To prevent overall efficiency changes due to variation of tube voltage, a regulated voltage supply is used, and it is normal practice to operate in the middle of the plateau to reduce the effect of any voltage variations.
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The input offset voltage (V_{os}) is a parameter defining the differential DC voltage required between the inputs of an amplifier, especially an operational amplifier (op-amp), to make the output zero (for voltage amplifiers, 0 volts with respect to ground or between differential outputs, depending on the output type).
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Cll1 targets, like the classical scorpion beta-toxin, the voltage-gated sodium channels (Nav). Beta- toxins bind to the extracellular end of the voltage sensor S4 at the loop between the 3rd and 4th segment of the second domain. By binding it alters the voltage dependent opening of the channel.
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Transmission networks are complex with redundant pathways. For example, see the map of the United States' (right) high-voltage transmission network. Network diagram of a high voltage transmission system, showing the interconnection between the different voltage levels. This diagram depicts the electrical structure of the network, rather than its physical geography.
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An additional limitation, often comparable to the effects of inductance, is the back-EMF of the motor. As the motor's rotor turns, a sinusoidal voltage is generated proportional to the speed (step rate). This AC voltage is subtracted from the voltage waveform available to induce a change in the current.
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The electrical division produces power and distribution transformers, high voltage switching gear, low voltage control gear, flame proof switch gear, voltage regulators and rectifiers, plant communication, and fire alarm and detection systems. The switchgear and electrical systems group is located in Kolkata, while the transformer & switchgear unit is located in Chennai.
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Their system converted higher voltage suitable for energy transmission to lower "service"-level voltage (step-down transformer). Nikola Tesla then proposed the use of step-up transformers, which would output higher voltage current than they received. This principle is widely used for power transmission over long distances all over the world.
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A rotary phase converter does not change the voltage, but it can be paired with a transformer to step the voltage up or down depending on what is needed.
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The relation between rated temperature TR and rated voltage UR as well as higher category temperature TC and derated category voltage UC is given in the picture at right.
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A circuit for automatically controlling amplifier gain in order to maintain a constant output voltage with a varying input voltage within a predetermined range of input-to-output variation.
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Trains that can operate on more than one voltage, say 3 kV/25 kV, are established technologies. Some locomotives in Europe are capable of using four different voltage standards.
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The capacitor must first be charged, usually from a battery whose voltage is lower than the voltage on the charged capacitor. This must be done in a controlled manner.
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A voltage converter is an electric power converter which changes the voltage of an electrical power source. It may be combined with other components to create a power supply.
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Potassium voltage-gated channel subfamily KQT member 4 also known as voltage- gated potassium channel subunit Kv7.4 is a protein that in humans is encoded by the KCNQ4 gene.
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By sensing the current provided to a load and using the device's applied voltage as a sensor voltage it is possible to determine the power dissipated by a device.
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As the membrane potential returns to its resting value, the voltage differential is not sufficient to keep the channel in its open state, causing the channel to close. Deactivation is the return of an ion channel to its closed conformation. For voltage-gated channels this occurs when the voltage differential that originally caused the channel to open returns to its resting value. In voltage-gated sodium channels, deactivation is necessary to recover from inactivation.
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In cases where ripple voltage is insignificant, like battery chargers, the input filter may be a single series resistor to adjust the output voltage to that required by the circuit. A resistor reduces both output voltage and ripple voltage proportionately. A disadvantage of a resistor input filter is that it consumes power in the form of waste heat that is not available to the load, so it is employed only in low current circuits.
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If a substantial part of a grid's load is electric motors, reducing voltage may not actually reduce load and can result in damage to customers' equipment. An unregulated direct current supply will produce a lower output voltage for electronic circuits. The output ripple voltage will decrease in line with the usually reduced load current. In a cathode-ray tube television, the reduced output voltage will make the screen image smaller, dimmer and fuzzier.
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Another method for suppressing voltage spikes is the transient-voltage-suppression diode (TVS). Although diodes do not have as much capacity to conduct large surges as MOVs, diodes are not degraded by smaller surges and can be implemented with a lower "clamping voltage". MOVs degrade from repeated exposure to surges and generally have a higher "clamping voltage" so that leakage does not degrade the MOV. Both types are available over a wide range of voltages.
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The magnitude of the emf for the battery (or other source) is the value of this 'open circuit' voltage. When the battery is charging or discharging, the emf itself cannot be measured directly using the external voltage because some voltage is lost inside the source. It can, however, be inferred from a measurement of the current I and voltage difference V, provided that the internal resistance r already has been measured: ℰ = V + Ir.
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Unlike a traditional incandescent lamp, an LED will light only when voltage is applied in the forward direction of the diode. No current flows and no light is emitted if voltage is applied in the reverse direction. If the reverse voltage exceeds the breakdown voltage, a large current flows and the LED will be damaged. If the reverse current is sufficiently limited to avoid damage, the reverse- conducting LED is a useful noise diode.
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A STATCOM is a voltage source converter (VSC)-based device, with the voltage source behind a reactor. The voltage source is created from a DC capacitor and therefore a STATCOM has very little active power capability. However, its active power capability can be increased if a suitable energy storage device is connected across the DC capacitor. The reactive power at the terminals of the STATCOM depends on the amplitude of the voltage source.
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Dynamic voltage restoration (DVR) is a method of overcoming voltage sags and swells that occur in electrical power distribution. These are a problem because spikes consume power and sags reduce efficiency of some devices. DVR saves energy through voltage injections that can affect the phase and wave- shape of the power being supplied. Devices used for DVR include static var devices, which are series compensation devices that use voltage source converters (VSC).
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High voltage cannot readily be used for lighting or motors, so transmission-level voltages must be reduced for end-use equipment. Transformers are used to change the voltage levels in alternating current (AC) transmission circuits. Transformers made voltage changes practical, and AC generators were more efficient than those using DC. These advantages led to early low voltage DC transmission systems being supplanted by AC systems around the turn of the 20th century.Hughes, Thomas Parke (1993).
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Cables of several hundred meters length can be used without a loss of signal quality. Supplying the IEPE sensor with constant current, results in a positive bias voltage, typically between 8 and 12 volts, at the output. The actual measuring signal of the sensor is added to this bias voltage. The supply or compliance voltage of the constant current source should be 24 to 30 V which is about two times the bias voltage.
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This may save up to 90 % power. Bias voltage and output voltage swing of an IEPE sensor Many measuring instruments designed for piezoelectric sensors or measurement microphones have an IEPE constant current source integrated at the input. In measuring instruments with IEPE input the bias voltage is often used for sensor detection. If the signal lies close to the constant current supply voltage, there is no sensor present or the cable path has been interrupted.
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The problem of contact resistance can be overcome by using four electrodes. The two end electrodes are used to inject current as before, but the voltage is measured between the two inner electrodes. The effective length of the sample being measured is the distance between the two inner electrodes. Modern voltage meters draw very little current so there is no significant current through the voltage electrodes and hence no voltage drop across the contact resistances.
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Electrical machines, which are energized and driven from the outside, induce a voltage which can be measured on the connection lines of the machine. The induced voltage is proportional to the speed and excitation. The course of the induced voltage gives information about the windings and the characteristics of the excitement around the circumference. The measurement of the induced voltage provides a simple method to diagnose the electromagnetic behavior of the motor.
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Minimizing power consumption in digital CMOS circuits requires significant design effort at all levels. Supply voltage reduction is one way to achieve this, but static supply voltage reduction can reduce performance. Dynamic voltage scaling systems are used to adjust the supply voltage to the specific operations the chip is performing. However, conventional DVS systems do not directly monitor the performance of the chip and must therefore accommodate operation under worst-case performance scenarios.
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The Dual-Voltage MultimediaCard (DV-MMC) is one of the first acceptable changes in MMC was the introduction of dual-voltage cards that can operate at 1.8 V in addition to 3.3 V. Running at lower voltages reduces the card's energy consumption, which is important in mobile devices. However, simple dual-voltage parts quickly went out of production in favour of MMCplus and MMCmobile which offer capabilities in addition to dual-voltage capability.
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Battery simulator able to set the simulated battery voltage either remotely via PC or manually. Often battery simulator has built- in voltage and current display and monitoring. For example the user selects the voltage of the battery to be simulated, using the potentiometer (knob) for adjusting the voltage, while the current value is displayed on the digital screen. An independent potentiometer is available to select the maximum current that the equipment can source or sink.
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Its leading products include 110 kV and above voltage level of high voltage switches (GIS, GCB, isolating switches, ground switches), transformers (power transformers, converter transformers), reactors (smoothing reactors, shunt reactors), power condensers, instrument transformers (CVT, CT, PT), insulators (power substation electric porcelain products, composite insulator products), cannula, zinc oxide arresters, direct current transportation valves, etc. China XD Group is the production base of high voltage, extra high voltage and extreme high voltage AC/DC power transmission and distribution equipment and other electrical products. As China's experimental research establishment of high voltage, intense current and large capacity AC/DC, XD Group's subordinate research institutions have become not only the member of the International Electrotechnical Commission (IEC) and International Conference on Large High Voltage Electric Systems (CIGRE), but also the specified administrative department of IEC in China and the relevant international Secretariat.
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The low voltage end of each choke is bypassed through a capacitor to ground, so any high voltage passing through the interwinding capacitance of the choke is bypassed to ground.
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High voltage is used for generating electron beams for microscopy. Cockcroft and Walton invented the voltage multiplier to transmutate lithium atoms in lithium oxide into helium by accelerating hydrogen atoms.
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The 866 is a mercury vapor half-wave rectifier intended for high-voltage applications. The voltage drop is approximately 15 volts up to 150 Hz. To avoid unwanted shorts the tube must be operated in a vertical position and the filament preheated for at least 30 seconds before applying the plate voltage.
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Presently, the driving voltage of blue phase LCs in IPS structures is still a little bit too high. To reduce the voltage, material engineering for developing high Kerr constant mixtures is critically important. Moreover, device design is also an effective way. With proper device structure design, the driving voltage can be largely reduced.
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Setting for x= λ for the rise of voltage sets V(x) equal to .63 Vmax. This means that the length constant is the distance at which 63% of Vmax has been reached during the rise of voltage. Setting for x= λ for the fall of voltage sets V(x) equal to .
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A TCR comprises two main items of equipment: the reactor itself, which is usually air-cored (although iron-cored reactors are possible) and the thyristor valve. Depending on the system voltage, an intermediate power transformer may be required to step up from the voltage handled by the thyristors to the transmission system voltage.
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Voltage transfer curve for a 20 μm inverter fabricated at North Carolina State University. Digital inverter quality is often measured using the voltage transfer curve (VTC), which is a plot of output vs. input voltage. From such a graph, device parameters including noise tolerance, gain, and operating logic levels can be obtained.
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But, inverters are also classified based on the type of input source. And they are, 1\. Voltage-source inverter (VSI) In this type of inverter, a constant voltage source acts as input to the inverter bridge. The constant voltage source is obtained by connecting a large capacitor across the DC source. 2\.
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This connection also provides a small degree of protection against low power supply voltage and loss of a phase. However, since contactor coils will hold the circuit closed with as little as 80% of normal voltage applied to the coil, this is not a primary means of protecting motors from low voltage operation.
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Plot of power dissipated vs. current in 4 devices. The constant voltage drop of a standard p-n junction diode is typically between 0.7 V and 1.7 V, causing significant power loss in the diode. Electric power depends on current and voltage: the power loss rises proportional to both current and voltage.
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The unit of reactance is the ohm. Inductive reactance resists the change to current, causing the circuit current to lag voltage. Capacitive reactance resists the change to voltage, causing the circuit current to lead voltage. 2 x ASCO 6MVA resistive/reactive containerised load banks testing diesel gen-sets on board a shipping vessel.
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Calciseptine has been shown to specifically inhibit the L-type voltage-gated Ca2+ channels and was the first natural polypeptide discovered with this property. Specific polypeptide inhibitors of voltage-sensitive channels are important tools in research, and were already known for voltage-sensitive Na+ channels, both voltage-sensitive and Ca2+-activated K+ channels, and for N-type Ca2+-channels. Before calciseptine was sequenced and shown to be a specific L-type calcium channel inhibitor, no specific polypeptide inhibitors were known for this type of voltage-gated channels. Specific blockers of the L-type channel were small organic molecules like 1,4-dihydropyridines.
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Also, a current source should not be connected to another current source if their currents differ but this arrangement is frequently used (e.g., in amplifying stages with dynamic load, CMOS circuits, etc.) Similarly, an ideal voltage source cannot be connected to an ideal short circuit (R = 0), since this would result a similar paradox of finite non-zero voltage across an element with defined zero voltage (the short circuit). Also, a voltage source should not be connected to another voltage source if their voltages differ but again this arrangement is frequently used (e.g., in common base and differential amplifying stages).
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An active regulator employs reactive components to store and discharge energy, so that most or all current supplied by the rectifier is passed to the load. It may also use negative and positive feedback in conjunction with at least one voltage amplifying component like a transistor to maintain output voltage when source voltage drops. The input filter must prevent the troughs of the ripple dropping below the minimum voltage required by the regulator to produce the required output voltage. The regulator serves both to significantly reduce the ripple and to deal with variations in supply and load characteristics.
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Circuit of a Brokaw bandgap reference Characteristic and balance point of T1 and T2 The voltage difference between two p–n junctions (e.g. diodes), operated at different current densities, is used to generate a current that is proportional to absolute temperature (PTAT) in a resistor. This current is used to generate a voltage in a second resistor. This voltage in turn is added to the voltage of one of the junctions (or a third one, in some implementations). The voltage across a diode operated at constant current is complementary to absolute temperature (CTAT), with a temperature coefficient of approximately −2mV/K.
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The Wiegand interface uses three wires, one of which is a common ground and two of which are data transmission wires usually called DATA0 and DATA1, alternately labeled "D0" and "D1" or "Data Low" and "Data High". When no data is being sent, both DATA0 and DATA1 are pulled up to the "high" voltage level — usually +5 VDC. When a 0 is sent the DATA0 wire is pulled to a low voltage while the DATA1 wire stays at a high voltage. When a 1 is sent the DATA1 wire is pulled to a low voltage while DATA0 stays at a high voltage.
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A single- phase induction regulator has a (primary) excitation winding, connected to the supply voltage, wound on a magnetic core which can be rotated. The stationary secondary winding is connected in series with the circuit to be regulated. As the excitation winding is rotated through 180 degrees, the voltage induced in the series winding changes from adding to the supply voltage to opposing it. By selection of the ratios of the number of turns on the excitation and series windings, the range of voltage can be adjusted, say, plus or minus 20% of the supply voltage, for example.
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Long term surges may or may not be handled by fuses and over voltage relays. A transient surge protector attempts to limit the voltage supplied to an electric device by either blocking or shorting current to reduce the voltage below a safe threshold. Blocking is done by using inductors which inhibit a sudden change in current. Shorting is done by spark gaps, discharge tubes, zener-type semiconductors, and MOVs (Metal Oxide Varistors), all of which begin to conduct current once a certain voltage threshold is reached, or by capacitors which inhibit a sudden change in voltage.
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DC to DC converters are used in portable electronic devices such as cellular phones and laptop computers, which are supplied with power from batteries primarily. Such electronic devices often contain several sub- circuits, each with its own voltage level requirement different from that supplied by the battery or an external supply (sometimes higher or lower than the supply voltage). Additionally, the battery voltage declines as its stored energy is drained. Switched DC to DC converters offer a method to increase voltage from a partially lowered battery voltage thereby saving space instead of using multiple batteries to accomplish the same thing.
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Potassium voltage-gated channel, subfamily H (eag-related), member 5, also known as KCNH5, is a human gene encoding the Kv10.2 protein. Voltage-gated potassium (Kv) channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. This gene encodes a member of the potassium channel, voltage-gated, subfamily H. This member is a pore-forming (alpha) subunit of a voltage-gated non-inactivating delayed rectifier potassium channel.
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"Lo-V" is short for "Low Voltage", which refers to the cars' form of propulsion control. Earlier Composite and "Hi-V" (High Voltage) equipment that ran on the IRT utilized a 600 volt DC circuit that ran directly through the motorman's master controller to control the car's propulsion. The 600 volts was also trainlined through the whole train by the use of high voltage jumper cables. However, Lo-V equipment used trainlined battery voltage (32 volts) in the motor control circuit to move high voltage (600 volts) contacts underneath each car, which would control the car's propulsion.
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Power dips are reductions in voltage, mostly of short duration (<300 ms) but sometimes longer. They may cause a number of problems with equipment, for example contactors and relays may drop out causing machinery to stop. There are a number of low voltage ride through techniques including Uninterruptible Power Supplies, the use of capacitors on low voltage DC control circuits, the use of capacitors on the DC bus of Variable Speed Drives. Care must be taken that Voltage Optimisation measures do not reduce the voltage to an extent that equipment is more vulnerable to power dips.
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Stray voltage is generally discovered during routine electrical work, or as a result of a customer complaint or shock incident. A growing number of utilities in urban areas now conduct routine periodic and systematic active tests for stray voltage (or more specifically, contact voltage) for public safety reasons. Some incipient electrical faults may also be discovered during routine work or inspection programs which are not specifically focused on stray voltage. Equipment used to detect stray voltage varies, but common devices are electrical tester pens or electric field detectors, with follow-up testing using a low-impedance voltmeter.
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The rising edge is the transition from a low voltage (level 1 in the diagram) to a high voltage (level 2). The falling edge is the transition from a high voltage to a low one. Although in a highly simplified and idealized model of a digital circuit, we may wish for these transitions to occur instantaneously, no real world circuit is purely resistive and therefore no circuit can instantly change voltage levels. This means that during a short, finite transition time the output may not properly reflect the input, and will not correspond to either a logically high or low voltage.
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The voltage rating of the fuse must be equal to or, greater than, what would become the open-circuit voltage. For example, a glass tube fuse rated at 32 volts would not reliably interrupt current from a voltage source of 120 or 230 V. If a 32 V fuse attempts to interrupt the 120 or 230 V source, an arc may result. Plasma inside the glass tube may continue to conduct current until the current diminishes to the point where the plasma becomes a non-conducting gas. Rated voltage should be higher than the maximum voltage source it would have to disconnect.
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The voltage clamp technique allows an experimenter to "clamp" the cell potential at a chosen value. This makes it possible to measure how much ionic current crosses a cell's membrane at any given voltage. This is important because many of the ion channels in the membrane of a neuron are voltage-gated ion channels, which open only when the membrane voltage is within a certain range. Voltage clamp measurements of current are made possible by the near-simultaneous digital subtraction of transient capacitive currents that pass as the recording electrode and cell membrane are charged to alter the cell's potential.
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Constant-voltage speaker systems are analogous to electrical power transmission methods employed by electric utility companies to transmit electric power over long distances. Typically, an electric utility will step up the voltage of the power transmitted, which correspondingly reduces the current, hence reducing the power loss during transmission. The voltage is stepped down at the destination. Similarly, in a constant-voltage speaker system, the amplifier uses a transformer to step up the voltage of the audio signal to reduce power loss over the speaker cable, allowing more power to be transmitted over a given wire diameter.
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It is used in situations where the tiny leakage of current through the insulating surfaces of a wire or PCB board would otherwise cause error in the measurements or functionality of the device. The basic principle is to shield the sensitive wire by surrounding it with a conductor that is held at the same voltage as the wire. If they are at the same voltage then there will be no current between the sensitive wire and the shield. This is typically achieved using a voltage buffer/follower that matches the guard voltage to the wire voltage.
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When the TSC is switched off, or ‘’blocked’’, no current flows and the voltage is supported by the thyristor valve. After the TSC has been switched off for a long time (hours) the capacitor will be fully discharged, and the thyristor valve will experience only the AC voltage of the SVC busbar. However, when the TSC turns off, it does so at zero current, corresponding to peak capacitor voltage. The capacitor only discharges very slowly, so the voltage experienced by the thyristor valve will reach a peak of more than twice the peak AC voltage, about half a cycle after blocking.
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Induction coils with open magnetic circuits are inefficient at transferring power to loads. Until about 1880, the paradigm for AC power transmission from a high voltage supply to a low voltage load was a series circuit. Open-core transformers with a ratio near 1:1 were connected with their primaries in series to allow use of a high voltage for transmission while presenting a low voltage to the lamps. The inherent flaw in this method was that turning off a single lamp (or other electric device) affected the voltage supplied to all others on the same circuit.
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A pole-mounted three-phase distribution transformer. Low-voltage feeders distributing power to households are placed below the transformer A low- voltage network or secondary network is a part of electric power distribution which carries electric energy from distribution transformers to electricity meters of end customers. Secondary networks are operated at a low voltage level, which is typically equal to the mains voltage of electric appliances. Most modern secondary networks are operated at AC rated voltage of 100–127 or 220–240 volts, at the frequency of 50 or 60 hertz (see mains electricity by country).
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Critical Path Monitoring Technique for Adaptive Voltage Scaling One way to determine the voltage-frequency relationship of the chip is to use a critical path emulator. The emulator is tuned during the manufacturing process to closely model the behavior of the chip, and adapts to environmental and process variations. Measuring the behavior of the emulator allows the supply voltage to be automatically adjusted such that the minimum voltage is supplied for the target task. A ring oscillator that operates at the same voltage as that of the rest of the chip can be used as a critical path emulator.
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Internal resistance model of a source of voltage A practical electrical power source which is a linear electric circuit may, according to Thévenin's theorem, be represented as an ideal voltage source in series with an impedance. This impedance is termed the internal resistance of the source. When the power source delivers current, the measured voltage output is lower than the no-load voltage; the difference is the voltage drop (the product of current and resistance) caused by the internal resistance. The concept of internal resistance applies to all kinds of electrical sources and is useful for analyzing many types of electrical circuits.
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Float voltage is the voltage at which a battery is maintained after being fully charged to maintain that capacity by compensating for self-discharge of the battery. The voltage could be held constant for the entire duration of the cell's operation (such as in an automotive battery) or could be held for a particular phase of charging by the charger. The appropriate float voltage varies significantly with the chemistry and construction of the battery, and ambient temperature. With the appropriate voltage for the battery type and with proper temperature compensation, a float charger may be kept connected indefinitely without damaging the battery.
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If the voltage increases beyond the design limit, the diode goes into avalanche breakdown, causing the harmful voltage to be conducted to ground. When used in this fashion, they are often referred to as clamping diodes or transient voltage suppressors because they fix or "clamp" the maximum voltage to a predetermined level. Avalanche diodes are normally specified for this role by their clamping voltage VBR and the maximum amount of transient energy they can absorb, specified by either energy (in joules) or i^2rt. Avalanche breakdown is not destructive as long as the diode is prevented from overheating.
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480 The cathode current through this resistor causes the desired voltage drop across the resistor and places the cathode at a positive dc voltage equal in magnitude to the negative grid bias voltage required. The grid circuit puts the grid at zero volts dc relative to negative side of the plate voltage supply, causing the grid voltage to be negative with respect to the cathode by the required amount. Directly heated cathode circuits connect the cathode bias resistor to the center tap of the filament transformer secondary or to the center tap of a low resistance connected across the filament.Ghirardi, Alfred A. (1932).
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Unlike the transistor switching the current at its output (i.e., current source), the trancitor transfers its input to the voltage output (i.e., voltage source), so an inverse relationship with each other.
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The control voltage can be used to occasionally adjust the reference frequency to a NIST source. Sophisticated designs may also adjust the control voltage over time to compensate for crystal aging.
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Constant-voltage lines can be driven by a conventional amplifier with external step-up transformer, an amplifier with an internal step-up transformer or a high- voltage amplifier with transformerless output.
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His was successful in effort to standardize voltages for transmission lines in Czechoslovakia in 1919 (220/380V for low voltage and 22kV/100kV for high-voltage lines) and power plug sockets.
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The behavior of the voltage is thus dependent on the behavior current and on how much charge accumulates. This is why the formal definition states that the current produces the voltage.
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The ability to measure quantitatively voltage and current allowed Georg Ohm, in 1827, to formulate Ohm's Law – that the voltage across a conductor is directly proportional to the current through it.
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For class E2 the test is conducted in an analogous way but with an increase in conductibility and lasting 144 hours and is followed by induced voltage and applied voltage tests.
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Higher voltages than rated voltage cause hydrogen gas formation or a short circuit. Standard supercapacitors with aqueous electrolyte normally are specified with a rated voltage of 2.1 to 2.3 V and capacitors with organic solvents with 2.5 to 2.7 V. Lithium-ion capacitors with doped electrodes may reach a rated voltage of 3.8 to 4 V, but have a lower voltage limit of about 2.2 V. Supercapacitors with ionic electrolytes can exceed an operating voltage of 3.5 V. Operating supercapacitors below the rated voltage improves the long-time behavior of the electrical parameters. Capacitance values and internal resistance during cycling are more stable and lifetime and charge/discharge cycles may be extended. Higher application voltages require connecting cells in series.
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Signal voltage is applied to terminals VX, control voltage to terminals VY. Operational amplifiers A1, A2 perform same voltage-to-current and current-to-voltage converter functions as their counterparts in unipolar log-antilog circuit, and maintain virtual ground potential at input and output nodes of the core. Values of feedback resistors are usually set at ( in early hybrid ICs); they must be equal to ensure unity gain at zero control voltage. Potentials of all nodes of the core other than Vy are almost independent of input signals, which is common to all current-mode circuits: they process signal currents, not voltages. When control voltage VY=0 the core operates as a bidirectional current follower, replicating input current I1 to output current I2.
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They remain an alternative (or a supplement) to capacitors for power factor correction because of problems that have been experienced with harmonics causing capacitor overheating and catastrophic failures. Synchronous condensers are also useful for supporting voltage levels. The reactive power produced by a capacitor bank is in direct proportion to the square of its terminal voltage, and if the system voltage decreases, the capacitors produce less reactive power, when it is most needed, while if the system voltage increases the capacitors produce more reactive power, which exacerbates the problem. In contrast, with a constant field, a synchronous condenser naturally supplies more reactive power to a low voltage and absorbs more reactive power from a high voltage, plus the field can be controlled.
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VFDs are available with voltage and current ratings covering a wide range of single-phase and multi-phase AC motors. Low-voltage (LV) drives are designed to operate at output voltages equal to or less than 690 V. While motor-application LV drives are available in ratings of up to the order of 5 or 6 MW, economic considerations typically favor medium-voltage (MV) drives with much lower power ratings. Different MV drive topologies (see Table 2) are configured in accordance with the voltage/current-combination ratings used in different drive controllers' switching devices such that any given voltage rating is greater than or equal to one to the following standard nominal motor voltage ratings: generally either .16 kV (60 Hz) or .
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Loudspeaker with attached step-down transformer for use on a constant-voltage system Constant-voltage speaker systems refer to networks of loudspeakers which are connected to an audio amplifier using step-up and step-down transformers to simplify impedance calculations and to minimize power loss over the speaker cables. They are more appropriately called high-voltage audio distribution systems. The voltage is constant only in the sense that at full power, the voltage in the system does not depend on the number of speakers driven (as long the amplifier's maximum power is not exceeded). Constant- voltage speaker systems are also commonly referred to as 25-, 70-, 70.7-, or 100-volt speaker systems; distributed speaker systems; or high-impedance speaker systems.
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However, usually in a homogeneous solid insulator after one region has broken down and become conductive there is no voltage drop across it, and the full voltage difference is applied to the remaining length of the insulator. Since the voltage drop is now across a shorter length, this creates a higher electric field in the remaining material, which causes more material to break down. So the breakdown region rapidly (within microseconds) spreads in the direction of the voltage gradient from one end of the insulator to the other, until a continuous conductive path is created through the material between the two contacts applying the voltage difference, allowing a current to flow between them. Electrical breakdown can also occur without an applied voltage, due to an electromagnetic wave.
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A common use of the voltage converter is for a device that allows appliances made for the mains voltage of one geographical region to operate in an area with different voltage. Such a device may be called a voltage converter, power converter, travel adapter, etc. Most single phase alternating-current electrical outlets in the world supply power at 210–240 V or at 100–120 V. A transformer or auto transformer can be used; (auto)transformers are inherently reversible, so the same transformer can be used to step the voltage up, or step it down by the same ratio. Lighter and smaller devices can be made using electronic circuitry; reducing the voltage electronically is simpler and cheaper than increasing it.
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Figure 1: An ideal current source, I, driving a resistor, R, and creating a voltage V A current source is an electronic circuit that delivers or absorbs an electric current which is independent of the voltage across it. A current source is the dual of a voltage source. The term current sink is sometimes used for sources fed from a negative voltage supply. Figure 1 shows the schematic symbol for an ideal current source driving a resistive load.
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Most sources of electrical energy (mains electricity, a battery, etc.) are best modeled as voltage sources. Such sources provide constant voltage, which means that as long as the current drawn from the source is within the source's capabilities, its output voltage stays constant. An ideal voltage source provides no energy when it is loaded by an open circuit (i.e., an infinite impedance), but approaches infinite power and current when the load resistance approaches zero (a short circuit).
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The high-voltage equipment must also supply the low voltage, above 5 V, for the cathode heating, and negative voltage up to about 1000 V for the control electrode. The electron gun also needs low-voltage supplies for the correction system, the focusing lens, and the deflection system. The last mentioned may be very complex if it is to provide computer-controlled imaging, engraving, or similar beam applications. Complex electronics may also be needed to control the workpiece manipulator.
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An ATX power supply unit with top cover removed A power supply unit (PSU) converts mains AC to low-voltage regulated DC power for the internal components of a computer. Modern personal computers universally use switched- mode power supplies. Some power supplies have a manual switch for selecting input voltage, while others automatically adapt to the mains voltage. Most modern desktop personal computer power supplies conform to the ATX specification, which includes form factor and voltage tolerances.
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Resistance characteristic of a transmission gate. VTHN and VTHP denote those positions at which the voltage to be switched has reached a potential, where the threshold voltage of the respective transistor is reached. When the control input is a logic zero (negative power supply potential), the gate of the n-channel MOSFET is also at a negative supply voltage potential. The gate terminal of the p-channel MOSFET is caused by the inverter, to the positive supply voltage potential.
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Thury developed this idea into the first commercial system for high-voltage DC transmission. Like Brush's dynamos, current is kept constant, and when increasing load demands more pressure, voltage is increased. The Thury System was successfully used on several DC transmission projects from Hydro generators. The first in 1885 was a low voltage system in Bözingen, and the first high voltage system went into service in 1889 in Genoa, Italy, by the Acquedotto de Ferrari-Galliera company.
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As the circuit voltage approaches near steady state, then the pre-charge function is complete. Normal operation of a pre-charge circuit is to terminate pre-charge mode when the circuit voltage is 90% or 95% of the operating voltage. Upon completion of pre-charging, the pre-charge resistance is switched out of the power supply circuit and returns to a low impedance power source for normal mode. The high voltage loads are then powered up sequentially.
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Voltage is an unincorporated community in Harney County, Oregon, United States. It is about south of Burns, on the south shore of Malheur Lake near the Donner und Blitzen River. Voltage post office was established in 1908 by Walter C. Botsford, the first postmaster, who was interested in electricity and thought that the river could generate enough "voltage" to serve the entire Harney Basin. He had confused voltage with power; a hydropower project was never attempted.
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Conductive materials should never be charge referenced unless the topmost layer of the sample has a thick non-conductive film. The charging effect, if needed, can also be compensated by providing suitable low energy charges to the surface by the use of low- voltage (1-20 eV) electron beam from an electron flood gun, UV lights, low- voltage argon ion beam with low-voltage electron beam (1-10 eV), aperture masks, mesh screen with low-voltage electron beams, etc.
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A voltage created by power- switching devices like IGBTs is not sinusoidal. It is a pulse-width modulated (PWM) waveform very high in harmonic distortion. This PWM voltage is then passed through an inductor/capacitor filter system that produces a sine-wave voltage with less than 3% total harmonic distortion (standards for computer grade power allow up to 5% THD). By contrast, VFDs generate a PWM voltage that limits their versatility and makes them unsuitable for many applications.
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Joule thief with regulated output voltage A simple modification of the previous schematic replaces the LED with three components to create a simple zener diode based voltage regulator. Diode D1 acts as a half-wave rectifier to allow capacitor C to charge up only when a higher voltage is available from the joule thief on the left side of diode D1. The Zener diode D2 limits the output voltage. A better solution is shown in the next schematic example.
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High-voltage differential (HVD) signaling uses high-voltage signals. In computer electronics, "high voltage" normally means 5 volts or more. SCSI-1 variations included a high voltage differential (HVD) implementation whose maximum cable length was many times that of the single- ended version. SCSI equipment for example allows a maximum total cable length of 25 meters using HVD, while single-ended SCSI allows a maximum cable length of 1.5 to 6 meters, depending on bus speed.
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The buffer amplifier charges or discharges the capacitor so that the voltage across the capacitor is practically equal, or proportional to, input voltage. In hold mode the switch disconnects the capacitor from the buffer. The capacitor is invariably discharged by its own leakage currents and useful load currents, which makes the circuit inherently volatile, but the loss of voltage (voltage drop) within a specified hold time remains within an acceptable error margin for all but the most demanding applications.
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The characteristic impedance is purely real, which means resistive for that impedance, and it is often called surge impedance for a lossless line. When a lossless line is terminated by surge impedance, there is no voltage drop. Though the phase angles of voltage and current are rotated, the magnitudes of voltage and current remain constant along the length of the line. For load > SIL, the voltage will drop from sending end and the line will “consume” VARs.
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The polarization of membranes is controlled by sodium, potassium, calcium, and chloride ion channels. There are two types of ion channels involved in the neuromuscular junction and end plate potentials: voltage-gated ion channel and ligand-gated ion channel. Voltage gated ion channels are responsive to changes in membrane voltage which cause the voltage gated ion channel to open and allows certain ions to pass through. Ligand gated ion channels are responsive to certain molecules such as neurotransmitters.
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Reducing voltage to an induction motor will slightly affect the motor speed as slip will increase, but speed is mainly a function of the supply frequency and the number of poles. Motor efficiency is optimum at reasonable load (typically 75%) and at the designed voltage, and will fall off slightly with small variations either side of this voltage. Larger variations affect efficiency more. Very lightly loaded motors (<25%) and small motors benefit most from reducing voltage.
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Organic photovoltaics, similar to inorganic photovoltaics, are generally characterized through current-voltage analysis. This analysis provides multiple device metrics values that are used to understand device performance. One of the most crucial metrics is the Power Conversion Efficiency (PCE). Organic Photovoltaic Current Voltage Curve PCE (η) is proportional to the product of the short-circuit current (JSC), the open circuit voltage (VOC), and the fill factor (FF), all of which can be determined from a current- voltage curve.
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Electronic voltage regulators are found in devices such as computer power supplies where they stabilize the DC voltages used by the processor and other elements. In automobile alternators and central power station generator plants, voltage regulators control the output of the plant. In an electric power distribution system, voltage regulators may be installed at a substation or along distribution lines so that all customers receive steady voltage independent of how much power is drawn from the line.
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Like other gas discharge lamps, the neon bulb has negative resistance; its voltage falls with increasing current after the bulb reaches its breakdown voltage. Therefore, the bulb has hysteresis; its turn-off (extinction) voltage is lower than its turn-on (breakdown) voltage. This allows it to be used as an active switching element. Neon bulbs were used to make relaxation oscillator circuits, using this mechanism, sometimes referred to as the Pearson–Anson effectGE Glow Lamp Manual 1965 , p.
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In binary logic the exact magnitude of the signal voltage is not critical and it is only necessary that 1 and 0 states be represented by detectably different voltage levels. In these examples at least one input of every gate must be connected to a voltage level providing the defined logic 1 or logic 0 levels. If all the inputs are disconnected from any driving source the output signal is not confined to the correct voltage range.
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Voltage is designated as the base to which current angle is compared, meaning that current is thought of as either "leading" or "lagging" voltage. Where the waveforms are purely sinusoidal, the power factor is the cosine of the phase angle (\varphi) between the current and voltage sinusoidal waveforms. Equipment data sheets and nameplates will often abbreviate power factor as "\cos \phi" for this reason. Example: The active power is and the phase angle between voltage and current is 45.6°.
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High voltage resistor divider probe for voltages up to 50 kV. The probe tip consists of a corona ball, which avoids corona discharge and arcing by distributing the electric field gradient. A high voltage probe allows an ordinary voltmeter to measure voltages that would otherwise be too high to measure or even destructive. It does this by reducing the input voltage to a safe, measurable level with a precision voltage divider circuit within the probe body.
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Early analog synthesizers used technology from electronic analog computers and laboratory test equipment. They were generally "modular" synthesizers, consisting of a number of independent electronic modules connected by patch cables into a patchbay that resembled the jackfields used by 1940s-era telephone operators. Synthesizer modules in early analog synthesizers included voltage-controlled oscillators (VCOs), voltage-controlled filters (VCFs), and voltage-controlled amplifiers (VCAs). The control voltage varied frequency in VCOs and VCFs, and attenuation (gain) in VCAs.
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The device collects power from the USB power source of the component it is connected to in its capacitors until it reaches a high voltage and then it discharges the high voltage onto the data pins. Versions 2, 3 and 4 of the device may generate a voltage of 215 to 220 volts. This device has been compared to the Etherkiller, a family of cables that feed mains electricity into low-voltage sockets such as RJ45.
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A null detector identifies when a given value is zero. Comparators are ideal for null detection comparison measurements, since they are equivalent to a very high gain amplifier with well-balanced inputs and controlled output limits. The null detector circuit compares two input voltages: an unknown voltage and a reference voltage, usually referred to as vu and vr. The reference voltage is usually on the non- inverting input (+), while the unknown voltage is usually on the inverting input (−).
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The burden voltage can be significant in very low-voltage circuit areas. To check for its effect on accuracy and on external circuit operation the meter can be switched to different ranges; the current reading should be the same and circuit operation should not be affected if burden voltage is not a problem. If this voltage is significant it can be reduced (also reducing the inherent accuracy and precision of the measurement) by using a higher current range.
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A PMIC may include battery management, voltage regulation, and charging functions. It may include a DC to DC converter to allow dynamic voltage scaling. Some models are known to feature up to 95% power conversion efficiency. Some models integrate with dynamic frequency scaling in a combination known as DVFS (dynamic voltage and frequency scaling).
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Edges of the resistive layer have conductive contacts. Locating the contact point is done by applying a voltage to opposite edges, leaving the other two edges temporarily unconnected. The voltage of the top layer provides one coordinate. Disconnecting those two edges, and applying voltage to the other two, formerly unconnected, provides the other coordinate.
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A protector may be larger to obtain a same let-through voltage during 3rd edition testing. Therefore, a 3rd edition or later protector should provide superior safety with increased life expectancy. A protector with a higher let-through voltage, e.g.400 V vs 330 V, will pass a higher voltage to the connected device.
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Diagram of a voltage-sensitive sodium channel α-subunit. G - glycosylation, P - phosphorylation, S - ion selectivity, I - inactivation, positive (+) charges in S4 are important for transmembrane voltage sensing. Voltage-gated sodium channels are proteins found in the membrane of neurons. When electrically activated, they allow the movement of sodium ions across a plasma membrane.
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Many voltage measurements cannot be made using conventional contacting voltmeters because they require charge transfer to the voltmeter, thus causing loading and modification of the source voltage. For example, when measuring voltage distribution on a dielectric surface, any measurement technique that requires charge transfer, no matter how small, will modify or destroy the actual data.
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A DC voltage can be used to control a UJT or PUT circuit such that the "on- period" increases with an increase in the DC control voltage. This application is important for large AC current control. UJTs can also be used to measure magnetic flux. The hall effect modulates the voltage at the PN junction.
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The flyback converter is an isolated power converter. The two prevailing control schemes are voltage mode control and current mode control (in the majority of cases current mode control needs to be dominant for stability during operation). Both require a signal related to the output voltage. There are three common ways to generate this voltage.
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A voltage follower reads the voltage on the input (caused by a small current through a big resistor). It then instructs a parallel circuit that has a large current source behind it (the electrical mains) and adjusts the resistance of that parallel circuit to give the same output voltage, but across a lower resistance.
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Voltages in this article are the nominal single-phase supply voltages, or split-phase supply voltages. Three-phase and industrial loads may have other voltages. All voltages are root mean square voltage; the peak AC voltage is greater by a factor of , and the peak-to-peak voltage greater by a factor of 2.
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Jopling J. M., Forster P. D., Holland D. C. and Hale R. E., 2004, Low Voltage Seismic Sound Source, US Patent No 6771565 These use capacitors on the towed sled, allowing efficient energy recovery, lower voltage power supplies and lighter cables. The low voltage systems are generally easier to deploy and have fewer safety concerns.
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This is often the case because voltage is taken as the reference. In circuits with primarily inductive loads, current lags the voltage. This happens because in an inductive load, it is the induced electromotive force that causes the current to flow. Note that in the definition above, the current is produced by the voltage.
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This is a list of high voltage (above 150 kV) AC electrical transmission lines. This list is incomplete. For high-voltage direct current, both underground and submarine, see List of HVDC projects.
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This can be prevented with the use of a separate layer insulation, which is needed anyway when the voltage difference between the layers exceeds the voltage strength of the copper wire insulation.
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A positive biased clamp A positive biased voltage clamp is identical to an equivalent unbiased clamp but with the output voltage offset by the bias amount VBIAS. Thus, VOUT = VIN \+ (VINpeak \+ VBIAS).
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This involves applying the operating voltage for some 10 minutes over a current limiting resistor to the terminals of the capacitor. Applying a voltage through a safety resistor repairs the oxide layers.
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Other signals include, for example, an indication that a passenger has requested a stop at a request stop, the voltage in a variable voltage section or an order to test the brakes.
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Power optimizers are essentially DC-DC converters, taking the DC power from a solar panel at whatever voltage and current is optimal (via MPPT), then converting that to a different voltage and current that best suits the central / string inverter. Some power optimizers are designed to work in conjunction with a central inverter from the same manufacturer, which allows the inverter to communicate with the optimizers to ensure that the inverter always receives the same total voltage from the panel string.SolarEdge Technical Note - Fixed String Voltage, Concept of Operation In this situation, if there is a string of panels in series and a single panel's output drops due to shade, its voltage will drop so that it can deliver the same amount of current (amps). This would cause the string voltage to drop as well, except that the central inverter adjusts all the other optimizers so that their output voltage increases slightly, maintaining the fixed string voltage required at the inverter (just at reduced available amperage while the single panel is shaded).
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The test is conducted on the high-voltage (HV) side of the transformer where the low-voltage (LV) side or the secondary is short circuited. A wattmeter is connected to the primary. An ammeter is connected in series with the primary winding. A voltmeter is optional since the applied voltage is the same as the voltmeter reading.
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This means a Gunn diode has a region of negative differential resistance in its current–voltage characteristic curve, in which an increase of applied voltage, causes a decrease in current. This property allows it to amplify, functioning as a radio frequency amplifier, or to become unstable and oscillate when it is biased with a DC voltage.
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Power distribution system voltage is nearly sinusoidal in nature. Voltages are expressed as root mean square (RMS) voltage. Voltage tolerances are for steady-state operation. Momentary heavy loads, or switching operations in the power distribution network, may cause short-term deviations out of the tolerance band and storms and other unusual conditions may cause even larger transient variations.
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At each customer's service, the step-down transformer has up to five taps to allow some range of adjustment, usually ±5% of the nominal voltage. Since these taps are not automatically controlled, they are used only to adjust the long-term average voltage at the service and not to regulate the voltage seen by the utility customer.
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That is, the feedback is then positive rather than negative. Frequency compensation is implemented to avoid this result. Another goal of frequency compensation is to control the step response of an amplifier circuit as shown in Figure 1. For example, if a step in voltage is input to a voltage amplifier, ideally a step in output voltage would occur.
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Low-voltage electron microscope (LVEM) is an electron microscope which operates at accelerating voltages of a few kiloelectronvolts or less. Traditional electron microscopes use accelerating voltages in the range of 10-1000 keV. Low voltage imaging in transmitted electrons is possible in many new scanning electron detector. Low cost alternative is dedicated table top low voltage transmission electron microscope.
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Cll1 binds to transmembrane segment S4 of the voltage gated sodium channels. Its binding shifts the activation threshold of the sodium channel towards more negative membrane potentials. Seven different isoforms of the voltage gated sodium channels (Nav1.1-Nav1.7) have been studied in the presence of Cll1. In almost all of these seven isoforms, Cll1 affects voltage dependent activation.
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This category describes a set of techniques in which one electrode is used for voltage clamp. Continuous single-electrode clamp (SEVC-c) technique is often used with patch-clamp recording. Discontinuous single-electrode voltage-clamp (SEVC-d) technique is used with penetrating intracellular recording. This single electrode carries out the functions of both current injection and voltage recording.
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These channels are responsible for propagation of electrical signals in nerve cells. Voltage- gated sodium channels can be divided into two subunits: alpha and beta. A variety of alpha subunit voltage-gated sodium channels have been identified. Voltage-gated sodium channels found in mammals can be divided into three types: Nav1.x, Nav2.x, and Nav3.x. Nav1.
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The electrostatic drum amplifier used a band wrapped partway around a rotating drum, and fixed at its anchored end to a spring. The other end connected to a speaker cone. The input signal was transformed up to high voltage, and added to a high voltage DC supply line. This voltage was connected between drum and belt.
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TV cascade (green) and flyback transformer (blue). The high- voltage supplies for CRTs often use voltage multipliers with the final-stage smoothing capacitor formed by the interior and exterior aquadag coatings on the CRT itself. CRTs were formerly a common component in television sets. Voltage multipliers can still be found in modern TVs, photocopiers, and bug zappers.
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The system ceases to provide current to the coil. This allows the counterbalance to pull the coil (and mass) upward through the magnetic field, which causes a voltage difference across the coil. The velocity measurement circuitry measures the speed of movement of the coil. This voltage is measured, using the same voltage standard and integrating voltmeter.
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This step provides automatic offset cancellation (i.e. the offset voltage represents nothing but dead charge, which can't be juggled by the capacitors). # All of the capacitors within the array are switched to the input signal Vin. The capacitors now have a charge equal to their respective capacitance times the input voltage minus the offset voltage upon each of them.
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In the laboratory, 4-AP is a useful pharmacological tool in studying various potassium conductances in physiology and biophysics. It is a relatively selective blocker of members of Kv1 (Shaker, KCNA) family of voltage-activated K+ channels. However, 4-AP has been shown to potentiate voltage-gated Ca2+ channel currents independent of effects on voltage-activated K+ channels.
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Above right a voltage regulator can be seen, formed by the current limiting resistor, R3, and the zener shunt regulator, IC1. If the voltage stability is not too important a Zener diode can be used as a regulator; the two-terminal device would eliminate R4 and R5 used as a resistive voltage divider in the schematic above.
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The breakdown characteristic of glow-discharge lamps allows them to be used as voltage regulators or overvoltage protection devices.Miller, W.G. (1969) Using and Understanding Miniature Neon Lamps , p.25-35 Starting around the 1930s, General Electric (GE), Signalite, and other firms made voltage regulator tubes. A voltage regulator tube was used in the Mark 6 exploder.
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Thyristor power controllers are operated with an alternating voltage in single-phase or three-phase. They are controlled by a controller and vary the activation time of the mains voltage for the load. Where the operating conditions do not require otherwise, the pulse group operation is recommended. Here, whole mains voltage shafts are switched to the load or blocked.
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Leakage transformers are used for arc welding and high voltage discharge lamps (neon lights and cold cathode fluorescent lamps, which are series connected up to 7.5 kV AC). It acts then both as a voltage transformer and as a magnetic ballast. Other applications are short-circuit-proof extra- low voltage transformers for toys or doorbell installations.
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Schematic of a MOSFET- controlled thyristor Positive voltage on the gate terminal with respect to the cathode turns the thyristor to the on state. Negative voltage on the gate terminal with respect to the anode, which is close to cathode voltage during the on state, turns the thyristor to the off state. MCTs were commercialized only briefly.
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This is often the case because voltage is taken as the reference. In circuits with primarily capacitive loads, current leads the voltage. This is true because current must first flow to the two plates of the capacitor, where charge is stored. Only after charge accumulates at the plates of a capacitor is a voltage difference established.
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Figure 1 above shows a comparator circuit. Note first that the circuit does not use feedback. The circuit amplifies the voltage difference between Vin and VREF, and it outputs the result at Vout. If Vin is greater than VREF, then voltage at Vout will rise to its positive saturation level; that is, to the voltage at the positive side.
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The CAM system instructs the electrical tester to apply a voltage to each contact point as required and to check that this voltage appears on the appropriate contact points and only on these.
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Usually a STATCOM is installed to support electricity networks that have a poor power factor and often poor voltage regulation. There are however, other uses, the most common use is for voltage stability.
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The vast majority of these systems (96%) are installed at the low voltage level and only 51 systems with (4%) a total capacity of 9.7 MW are installed at the medium voltage level.
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Potassium voltage-gated channel subfamily B member 2 is a protein that in humans is encoded by the KCNB2 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
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Potassium voltage-gated channel subfamily F member 1 is a protein that in humans is encoded by the KCNF1 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
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Potassium voltage-gated channel subfamily G member 2 is a protein that in humans is encoded by the KCNG2 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
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Potassium voltage-gated channel subfamily G member 3 is a protein that in humans is encoded by the KCNG3 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
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Potassium voltage-gated channel subfamily G member 4 is a protein that in humans is encoded by the KCNG4 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
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Potassium voltage-gated channel subfamily H member 6 is a protein that in humans is encoded by the KCNH6 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
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Potassium voltage-gated channel subfamily H member 7 is a protein that in humans is encoded by the KCNH7 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
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Potassium voltage-gated channel subfamily H member 8 is a protein that in humans is encoded by the KCNH8 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
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Potassium voltage-gated channel subfamily H member 3 is a protein that in humans is encoded by the KCNH3 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
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Potassium voltage-gated channel subfamily H member 4 is a protein that in humans is encoded by the KCNH4 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
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Voltage-gated potassium channel subunit beta-3 is a protein that in humans is encoded by the KCNAB3 gene. The protein encoded by this gene is a voltage- gated potassium channel beta subunit.
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Potassium voltage-gated channel subfamily S member 1 is a protein that in humans is encoded by the KCNS1 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
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Potassium voltage-gated channel subfamily S member 2 is a protein that in humans is encoded by the KCNS2 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
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Modern designs now use solid state technology (transistors) to perform the same function that the relays perform in electromechanical regulators. Electromechanical regulators are used for mains voltage stabilisation -- see AC voltage stabilizers below.
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This is easier to see when a capacitor "commutates" the control voltage or current; the ringing oscillation carries the control voltage or current from negative (switch open) through 0 to positive (switch closed).
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Lowering the voltage applied increases the reliability and reduce the expected failure rate.Ch. Reynolds, AVX, Technical Information, Reliability Management of Tantalum Capacitors, PDF Applying a higher voltage than specified may destroy electrolytic capacitors.
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Thus, all subway cars delivered afterward were low voltage cars.
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AR3 has recently been introduced as a fluorescent voltage sensor.
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Low voltage can eventually cause damage to the fuel injectors.
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An increase in voltage or power, usually expressed in dB.
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This compensating voltage is the negative of the Volta potential.
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As all new locomotives were ordered in three versions at that time (DC-only, AC-only, dual-voltage), the same applied to the "Danseuses" locomotives: a dual-voltage version, called BB25500 was ordered later in the early 1960s but was part of the same locomotive family as BB8500 and BB17000 locomotives. In order to get an idea of how to realise the first "real" dual-voltage locomotive, the damaged BB16540 locomotive was rebuilt in 1959 to dual-voltage and renumbered BB20004.
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Additionally, the capacitor may be labeled with its working voltage, temperature and other relevant characteristics. For typographical reasons, some manufacturers print MF on capacitors to indicate microfarads (μF). ;Example A capacitor labeled or designated as 473K 330V has a capacitance of 47 × 103 pF = 47 nF (±10%) with a maximum working voltage of 330 V. The working voltage of a capacitor is nominally the highest voltage that may be applied across it without undue risk of breaking down the dielectric layer.
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Peak repetitive off voltage is the maximum, instantaneous value of the off-state voltage that occurs across a thyristor, including all repetitive transient voltages and excluding all non-transient voltages. Peak repetitive reverse voltage is the maximum peak reverse voltage that may be applied continuously to the main terminals (anode and cathode) of quadracs. RMS on-state current is the maximum RMS current allowed for the specified use-case temperature. Temperature junction for quadracs is expressed as a full-required range.
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Full wave rectified ac is more commonly known as Rectified AC. PDC has some characteristics of both alternating current (AC) and direct current (DC) waveforms. The voltage of a DC wave is roughly constant, whereas the voltage of an AC waveform continually varies between positive and negative values. Like an AC wave, the voltage of a PDC wave continually varies, but like a DC wave, the sign of the voltage is constant. Pulsating direct current is used on PWM controllers.
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Most modern electronic items function using a DC voltage, so the PDC waveform must usually be smoothed before use. A reservoir capacitor converts the PDC wave into a DC waveform with some superimposed ripple. When the PDC voltage is initially applied, it charges the capacitor, which acts as a short term storage device to keep the output at an acceptable level while the PDC waveform is at a low voltage. Voltage regulation is often also applied using either linear or switching regulation.
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A pair of electronic 2.4 kW dimmers for tungsten incandescent lampsA dimmer is a device used to vary the average voltage applied to an instrument's lamp. The brightness of a lamp depends on its electric current, which in turn depends on the applied lamp voltage. When the applied voltage is decreased, a lamp's electric current will also decrease, thus reducing the light output from the lamp (dimming it). Conversely, a higher voltage will cause higher lamp current and increased (brighter) light output.
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Threshold switching occurs when GeSbTe goes from a high resistive state to a conductive state at the threshold field of about 56 V/um. This can be seen from the current-voltage (IV) plot, where current is very low in the amorphous state at low voltage until threshold voltage is reached. Current increases rapidly after the voltage snapback. The material is now in the amorphous "ON" state, where the material is still amorphous, but in a pseudo-crystalline electric state.
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The most commonly used test for the investigation of TDDB behavior is "constant stress". Constant stress tests can be applied in form of constant voltage stress (CVS) or constant current stress. In the former, a voltage (that is often lower than the breakdown voltage of the oxide) is applied to the gate, while its leakage current is being monitored. The time it will take for the oxide to break under this constant applied voltage is called the time- to-failure.
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A direct-current power source (generator or rectifier) having drooping characteristics and open circuit voltage of 70 volts or above is suitable for plasma arc welding. Rectifiers are generally preferred over DC generators. Working with helium as an inert gas needs open circuit voltage above 70 volts. This higher voltage can be obtained by series operation of two power sources; or the arc can be initiated with argon at normal open-circuit voltage and then helium can be switched on.
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One of the most potent known natural toxins, it acts on the voltage-gated sodium channels of neurons, preventing normal cellular function and leading to paralysis. The voltage-gated sodium channel is essential for normal neuronal functioning. It exists as integral membrane proteins interspersed along the axon of a neuron and possessing four domains that span the cell membrane. Opening of the voltage-gated sodium channel occurs when there is a change in voltage or some ligand binds in the right way.
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The formula describing a current divider is similar in form to that for the voltage divider. However, the ratio describing current division places the impedance of the considered branches in the denominator, unlike voltage division where the considered impedance is in the numerator. This is because in current dividers, total energy expended is minimized, resulting in currents that go through paths of least impedance, hence the inverse relationship with impedance. Comparatively, voltage divider is used to satisfy Kirchhoff's Voltage Law (KVL).
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However, this could be dangerous for motormen and shop personnel alike by creating an electrocution hazard. Even unpowered trailer cars had to carry the 600 volts through these jumpers because it was necessary to pass on the voltage to motor cars behind the trailer so as to synchronize them with the lead car. However, low voltage propulsion control utilized battery voltage (32 volts) to control the train's motors. This battery voltage was what would pass through the motorman's control stand and between cars.
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An example is the p–n junction diode (curve at right). As seen in the figure, the current does not increase linearly with applied voltage for a diode. One can determine a value of current (I) for a given value of applied voltage (V) from the curve, but not from Ohm's law, since the value of "resistance" is not constant as a function of applied voltage. Further, the current only increases significantly if the applied voltage is positive, not negative.
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Aluminum electrolytic capacitors with non-solid electrolyte are relatively insensitive to high and short-term transient voltages higher than the surge voltage, if the frequency and the energy content of the transients is low. This ability depends on the rated voltage and component size. Low energy transient voltages lead to a voltage limitation similar to a zener diode. The electrochemical oxide forming processes take place when voltage in correct polarity is applied and generates an additional oxide when transients arise.
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Many maintenance workers carry NCVD pens or AC voltage detectors in their tool belts. This portable device allows workers to quickly check electrical conductors for live voltage without actually touching the bare wire. The NCVD can sense voltage when positioned close to the live conductor without making a hard-wired electrical connection. A voltage portal is used to assist workers in creating an electrically safe work condition as part of a lockout-tagout procedure before beginning work on electrical or mechanical equipment.
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Most LEDs have low reverse breakdown voltage ratings, so they will also be damaged by an applied reverse voltage above this threshold. The cause of damage is overcurrent resulting from the diode breakdown, not the voltage itself. LEDs driven directly from an AC supply of more than the reverse breakdown voltage may be protected by placing a diode (or another LED) in inverse parallel. The manufacturer will normally advise how to determine the polarity of the LED in the product datasheet.
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A capacitor-input filter is a filter circuit in which the first element is a capacitor connected in parallel with the output of the rectifier in a linear power supply. The capacitor increases the DC voltage and decreases the ripple voltage components of the output. The capacitor is often referred to as a smoothing capacitor or reservoir capacitor. The capacitor is often followed by other alternating series and parallel filter elements to further reduce ripple voltage, or adjust DC output voltage.
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The locomotives in a consisted set are switched between series and parallel mode automatically, based on speed, overhead voltage and electromotive force (EMF). The driver can select "series hold" to force some or all of the locomotives in the consisted set to remain in series mode when overhead voltage is low. If nothing is done, some of the locomotives will switch off under low overhead voltage conditions, to prevent damage to resistors, and switch on again when the voltage improves.
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An avalanche diode displays a similar stable voltage over a range of current. The most stable diodes of this type are made by temperature-compensating a Zener diode by placing it in series with a forward diode; such diodes are made as two-terminal devices, e.g. the 1N821 series having an overall voltage drop of 6.2 V at 7.5 mA, but are also sometimes included in integrated circuits. The most common voltage reference circuit used in integrated circuits is the bandgap voltage reference.
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Schematic of a low-dropout regulator The main components are a power FET and a differential amplifier (error amplifier). One input of the differential amplifier monitors the fraction of the output determined by the resistor ratio of R1 and R2. The second input to the differential amplifier is from a stable voltage reference (bandgap reference). If the output voltage rises too high relative to the reference voltage, the drive to the power FET changes to maintain a constant output voltage.
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The capacitance arises from various sources, mainly transistors (primarily gate capacitance and diffusion capacitance) and wires (coupling capacitance). Toggling a voltage at a circuit node requires charging or discharging the capacitance at that node; since currents are related to voltage, the time it takes depends on the voltage applied. By applying a higher voltage to the devices in a circuit, the capacitances are charged and discharged more quickly, resulting in faster operation of the circuit and allowing for higher frequency operation.
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There have been some efforts to mitigate voltage and frequency issues due to increased implementation of DG. Most notably, IEEE 1547 sets the standard for interconnection and interoperability of distributed energy resources. IEEE 1547 sets specific curves signaling when to clear a fault as a function of the time after the disturbance and the magnitude of the voltage irregularity or frequency irregularity. Voltage issues also give legacy equipment the opportunity to perform new operations. Notably, inverters can regulate the voltage output of DGs.
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The Kelvin-Varley voltage divider, named after its inventors William Thomson, 1st Baron Kelvin and Cromwell Fleetwood Varley, is an electronic circuit used to generate an output voltage as a precision ratio of an input voltage, with several decades of resolution. In effect, the Kelvin–Varley divider is an electromechanical precision digital-to-analog converter. The circuit is used for precision voltage measurements in calibration and metrology laboratories. It can achieve resolution, accuracy and linearity of 0.1 ppm (1 in 10 million).
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The Mother-32 is a semi-modular analog synthesizer. Introduced in 2015, it was the first tabletop unit produced by Moog Music. It has a single voltage controlled audio oscillator, a voltage controlled low frequency oscillator, a voltage controlled filter switchable between high and low pass, an AR envelope generator with switchable sustain, a voltage controlled amplifier, and a white noise generator. It also features a 32–step monophonic sequencer , a 13-note keypad, and a 32-point patch bay including assignable outputs.
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Depending on the type of alternating current supply and the arrangement of the rectifier circuit, the output voltage may require additional smoothing to produce a uniform steady voltage. Many applications of rectifiers, such as power supplies for radio, television and computer equipment, require a steady constant DC voltage (as would be produced by a battery). In these applications the output of the rectifier is smoothed by an electronic filter, which may be a capacitor, choke, or set of capacitors, chokes and resistors, possibly followed by a voltage regulator to produce a steady voltage. More complex circuitry that performs the opposite function, that is converting DC to AC, is called an inverter.
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The potential gradient (electric field) across an insulator is not uniform, but is highest at the end next to the high voltage electrode. If subjected to a high enough voltage, the insulator will break down and become conductive at that end first. Once a section of insulator at the end has electrically broken down and become conductive, the full voltage is applied across the remaining length, so the breakdown will quickly progress from the high voltage end to the other, and a flashover arc will start. Therefore, insulators can stand significantly higher voltages if the potential gradient at the high voltage end is reduced.
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Three-phase systems can be connected to give various combinations of voltage, suitable for use by different classes of equipment. Where both single-phase and three-phase loads are served by an electrical system, the system may be labelled with both voltages such as 120/208 or 230/400 V, to show the line-to-neutral voltage and the line-to-line voltage. Large loads are connected for the higher voltage. Other three-phase voltages, up to 830 volts, are occasionally used for special-purpose systems such as oil well pumps. Large industrial motors (say, more than 250 hp or 150 kW) may operate on medium voltage.
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Conventional alternating current power is a sinusoidal voltage pattern that repeats over a defined period. That means that during a single cycle, the voltage passes through zero two times. In European systems the voltage at the plug has a maximum of 230 V and cycles 50 times a second, meaning that there are 100 times a second where the voltage is zero, while North American derived systems are 120 V 60 Hz, or 120 zero voltages a second. Inexpensive inverters can convert DC power to AC by simply turning the DC side of the power on and off 120 times a second, inverting the voltage every other cycle.
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The first voltage sensitive phosphatase was discovered as a result of a genome-wide search in the sea squirt Ciona intestinalis. The search was designed to identify proteins which contained a sequence of amino acids called a voltage sensor, because this sequence of amino acids confers voltage sensitivity to voltage- gated ion channels. Although the initial genomic analysis was primarily concerned with the evolution of voltage-gated ion channels, one of the results of the work was the discovery of the VSP protein in sea squirt, termed Ci-VSP. The homologues to Ci-VSP in mammals are called Transmembrane phosphatases with tensin homology, or TPTEs.
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Low voltage heating films are usually designed to function at voltages within SELV range and therefore present no danger of shock. Operation at such voltages means that the films have many fewer limitations on where and how they can be installed, however higher currents are required for operation, requiring thicker wires and voltage converting isolation transformers or power supplies to run from the local mains. Alternatively, low voltage heating films may be suitable for off grid installations where battery, solar, wind or other power is available at the required voltage and current. Low voltage heating films can be particularly suitable for use in wet areas, where water ingress is a possibility.
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However, stages are coupled capacitively to ground and serially to each other, and thus each stage encounters a voltage rise that is increasingly weaker the further the stage is from the switching one; the adjacent stage to the switching one therefore encounters the largest voltage rise, and thus switches in turn. As more stages switch, the voltage rise to the remainder increases, which speeds up their operation. Thus a voltage rise fed into the first stage becomes amplified and steepened at the same time. In electrodynamic terms, when the first stage breaks down it creates a spherical electromagnetic wave whose electric field vector is opposed to the static high voltage.
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Any increase of the drain-to-source voltage will increase the distance from drain to the pinch-off point, increasing the resistance of the depletion region in proportion to the drain-to-source voltage applied. This proportional change causes the drain-to-source current to remain relatively fixed, independent of changes to the drain-to-source voltage, quite unlike its ohmic behavior in the linear mode of operation. Thus, in saturation mode, the FET behaves as a constant-current source rather than as a resistor, and can effectively be used as a voltage amplifier. In this case, the gate-to-source voltage determines the level of constant current through the channel.
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Electromechanical regulators called voltage stabilizers or tap-changers, have also been used to regulate the voltage on AC power distribution lines. These regulators operate by using a servomechanism to select the appropriate tap on an autotransformer with multiple taps, or by moving the wiper on a continuously variable auto transfomer. If the output voltage is not in the acceptable range, the servomechanism switches the tap, changing the turns ratio of the transformer, to move the secondary voltage into the acceptable region. The controls provide a dead band wherein the controller will not act, preventing the controller from constantly adjusting the voltage ("hunting") as it varies by an acceptably small amount.
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If all inputs A and B and C are at 0 volts (logic level 0), current flowing through R will pull the output voltage down until the diodes clamp the output. Since these diodes are treated as ideal, the output is clamped to 0 volts, which is logic level 0. If any input switches to a positive voltage (logic 1), current flowing through the now forward-biased diode will pull the output voltage up, providing a positive voltage at the output, a logic 1. Any positive voltage will represent a logic 1 state; the summing of currents through multiple diodes does not change the logic level.
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A voltage-sourced converter can therefore feed power to an AC network consisting only of passive loads, something which is impossible with LCC HVDC. Voltage-source converters are also considerably more compact than line-commutated converters (mainly because much less harmonic filtering is needed) and are preferable to line- commutated converters in locations where space is at a premium, for example on offshore platforms. In contrast to line-commutated HVDC converters, voltage- source converters maintain a constant polarity of DC voltage and power reversal is achieved instead by reversing the direction of current. This makes voltage-source converters much easier to connect into a Multi-terminal HVDC system or “DC Grid”.
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A thermocouple probe Temperature probes are used to make contact measurements of surface temperatures. They employ a temperature sensor such as a thermistor, thermocouple, or RTD, to produce a voltage that varies with temperature. In the case of thermistor and RTD probes, the sensor must be electrically stimulated to produce a voltage, whereas thermocouple probes do not require stimulation because a thermocouple will independently produce an output voltage. Voltmeters can sometimes be used to measure temperature probes, but this task is usually delegated to specialized instruments that will stimulate the probe's sensor (if necessary), measure the probe's output voltage, and convert the voltage to temperature units.
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This method is often used with nickel–cadmium cells, which display a large voltage drop at full charge. However, the voltage drop is much less pronounced for NiMH and can be non-existent at low charge rates, which can make the approach unreliable. Another option is to monitor the change of voltage with respect to time and stop when this becomes zero, but this risks premature cutoffs. With this method, a much higher charging rate can be used than with a trickle charge, up to 1 C. At this charge rate, Panasonic recommends to terminate charging when the voltage drops 5–10 mV per cell from the peak voltage.
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The depolarized voltage opens additional voltage- dependent potassium channels, and some of these do not close right away when the membrane returns to its normal resting voltage. In addition, further potassium channels open in response to the influx of calcium ions during the action potential. The intracellular concentration of potassium ions is transiently unusually low, making the membrane voltage Vm even closer to the potassium equilibrium voltage EK. The membrane potential goes below the resting membrane potential. Hence, there is an undershoot or hyperpolarization, termed an afterhyperpolarization, that persists until the membrane potassium permeability returns to its usual value, restoring the membrane potential to the resting state.
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The Jindo–Jeju HVDC system is owned and operated by Korea Electric Power Corporation (KEPCO). The cables were designed and built by LS Cable and System and the converter stations were designed and built by Alstom Grid. The scheme is bipolar but unlike the Haenam–Cheju connection, which used a relatively conventional arrangement with two high-voltage cables and a sea return, Jindo–Jeju HVDC system uses metallic return with a total of four cables: three high-voltage cables and one medium-voltage cable. The high- voltage cables use mass-impregnated paper as the insulation material while the medium-voltage cable uses Cross-linked polyethylene (XLPE) insulation.
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The negative impedance converter (NIC) is a one-port op-amp circuit acting as a negative load which injects energy into circuits in contrast to an ordinary load that consumes energy from them. This is achieved by adding or subtracting excessive varying voltage in series to the voltage drop across an equivalent positive impedance. This reverses the voltage polarity or the current direction of the port and introduces a phase shift of 180° (inversion) between the voltage and the current for any signal generator. The two versions obtained are accordingly a negative impedance converter with voltage inversion (VNIC) and a negative impedance converter with current inversion (INIC).
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The charger will detect that a battery has been connected and the charging process will begin. The simulator keeps the voltage constant at the set value, while the analogue ammeter indicates the charging current. If the battery simulator has current limit feature and if the current exceed the maximum set value, the simulator automatically increases the voltage to limit the current The advantage a battery simulator is its ability to freely set the emulated battery voltage to any value in order to test the charger. For example, a real charger profile curved is obtained by sweeping the simulator voltage while recording its voltage and current.
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Similarly in defining a variable v representing the voltage between two terminals, the terminal which is positive when the voltage is positive must be specified, usually with a plus sign. This is called the reference direction or reference terminal for voltage v. If the terminal marked positive actually has a lower voltage than the other one, then the variable v will have a negative value. To understand the passive sign convention, it is important to distinguish the reference directions of the variables, v and i, which can be assigned at will, from the direction of the actual voltage and current, which is determined by the circuit.
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Foxton technology includes a highly advanced clock generation and distribution network. With this technology, the processor continuously measures total power draw, processor loads, voltage, and clock distribution quality across the entire device, and is able to produce extremely fine clock- to-voltage granularity under dynamic conditions. As a result, Foxton enables a processor to override factory adjusted settings, which are set at relatively high voltage levels at any given frequency to ensure stability against random voltage variances. By dynamically controlling voltage and frequencies across the entire device, Foxton is able to optimize performance for specific workloads, while ensuring that power consumption remains below specified thresholds.
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The tube was originally designed for mobile operations, so its filament draws only 0.705 amps of current, while anode power dissipation allowed is up to 40 watts, quite big for such low filament power. It determines the need for high anode voltage, 800 V typically. The screen grid is quite dense, so its voltage when working in pentode mode is limited by 300 volts, otherwise power dissipated by the grid when anode voltage goes below screen grid voltage would damage it. That's why the tube cannot be efficiently used in so-called "Ultra - Linear" regime when anode and screen grid have the same voltage at idle.
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Unlike with capacitors, the amount of reactive power supplied is proportional to voltage, not the square of voltage; this improves voltage stability on large networks. Synchronous condensers are often used in connection with high-voltage direct-current transmission projects or in large industrial plants such as steel mills. For power factor correction of high-voltage power systems or large, fluctuating industrial loads, power electronic devices such as the Static VAR compensator or STATCOM are increasingly used. These systems are able to compensate sudden changes of power factor much more rapidly than contactor-switched capacitor banks, and being solid-state require less maintenance than synchronous condensers.
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A digital buffer serves to transfer a voltage from a circuit that has a high output impedance level, to a second circuit with a low input impedance level. If we have a power source and a low impedance (resistor) load without a buffer, according to Ohm's law (voltage is equal to current times resistance), a huge amount of current is drawn from the source. As a result, huge amounts of power is drawn by the power source, which causes high disturbances. A voltage buffer always has a very high input impedance, approaching infinity; as a result, no matter what value the load impedance is, the source voltage will be totally spanned on the buffer impedance (because of Ohm's law); the voltage across the buffer impedance is the input voltage.
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Line voltage thermostats are most commonly used for electric space heaters such as a baseboard heater or a direct-wired electric furnace. If a line voltage thermostat is used, system power (in the United States, 120 or 240 volts) is directly switched by the thermostat. With switching current often exceeding 40 amperes, using a low voltage thermostat on a line voltage circuit will result at least in the failure of the thermostat and possibly a fire. Line voltage thermostats are sometimes used in other applications, such as the control of fan-coil (fan powered from line voltage blowing through a coil of tubing which is either heated or cooled by a larger system) units in large systems using centralized boilers and chillers, or to control circulation pumps in hydronic heating applications.
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Types of direct current The term DC is used to refer to power systems that use only one polarity of voltage or current, and to refer to the constant, zero-frequency, or slowly varying local mean value of a voltage or current. For example, the voltage across a DC voltage source is constant as is the current through a DC current source. The DC solution of an electric circuit is the solution where all voltages and currents are constant. It can be shown that any stationary voltage or current waveform can be decomposed into a sum of a DC component and a zero-mean time-varying component; the DC component is defined to be the expected value, or the average value of the voltage or current over all time.
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Because the pull-up resistor is external and does not need to be connected to the chip supply voltage, a lower or higher voltage than the chip supply voltage can be used instead (providing it does not exceed the absolute maximum rating of the chip's output). Open collector circuits are therefore sometimes used to interface different families of devices that have different operating voltage levels. The open- collector transistor can be rated to withstand a higher voltage than the chip supply voltage. This technique is commonly used by logic circuits operating at 5 V or lower to drive devices such as motors, 12 V relays, 50 V vacuum fluorescent displays, or Nixie tubes requiring more than 100 V. Another advantage is that more than one open-collector output can be connected to a single line.
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The Model T magneto (built into the flywheel) differed from modern implementations by not providing high voltage directly at the output; the maximum voltage produced was about 30 volts, and therefore also had to be run through the spark coil to provide high enough voltage for ignition, as described above, although the coil would not "buzz" continuously in this case, only going through one cycle per spark. In either case, the low voltage was switched to the appropriate spark plug by the timer mounted on the front of the engine. This performed the equivalent function to the modern distributor, although by directing the low voltage, not the high voltage as for the distributor. The ignition timing was adjustable by rotating this mechanism through a lever mounted on the steering column.
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As a result, IGBTs can be used to make self-commutated converters which are closer to a large inverter in operation. In such converters, the polarity of DC voltage is usually fixed and the DC voltage, being smoothed by a large capacitance, can be considered constant. For this reason, an HVDC converter using IGBTs is usually referred to as a voltage-source converter (or voltage- sourced converterHigh-voltage direct current (HVDC) power transmission using voltage sourced converters (VSC), IEC/TR 62543:2011.). The additional controllability gives many advantages, notably the ability to switch the IGBTs on and off many times per cycle in order to improve the harmonic performance, and the fact that (being self-commutated) the converter no longer relies on synchronous machines in the AC system for its operation.
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BJT bistable collector-base coupled circuit can be converted to a Schmitt trigger by connecting an additional base resistor to one of the bases Like every latch, the fundamental collector-base coupled bistable circuit possesses a hysteresis. So, it can be converted to a Schmitt trigger by connecting an additional base resistor R to one of the inputs (Q1 base in the figure). The two resistors R and R4 form a parallel voltage summer (the circle in the block diagram above) that sums output (Q2 collector) voltage and the input voltage, and drives the single-ended transistor "comparator" Q1. When the base voltage crosses the threshold (VBE0 ∞ 0.65 V) in some direction, a part of Q2's collector voltage is added in the same direction to the input voltage.
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In the past, the subthreshold conduction of transistors has usually been very small in the off state, as gate voltage could be significantly below threshold; but as voltages have been scaled down with transistor size, subthreshold conduction has become a bigger factor. Indeed, leakage from all sources has increased: for a technology generation with threshold voltage of 0.2 V, leakage can exceed 50% of total power consumption. The reason for a growing importance of subthreshold conduction is that the supply voltage has continually scaled down, both to reduce the dynamic power consumption of integrated circuits (the power that is consumed when the transistor is switching from an on-state to an off-state, which depends on the square of the supply voltage), and to keep electric fields inside small devices low, to maintain device reliability. The amount of subthreshold conduction is set by the threshold voltage, which sits between ground and the supply voltage, and so has to be reduced along with the supply voltage.
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The changing primary current causes a changing magnetic field ("flux") through the transformer's windings; this changing field induces a (relatively) steady secondary voltage Vs = N×Vb. In some designs (as shown in the diagrams) the secondary voltage Vs adds to the source voltage Vb; in this case because the voltage across the primary (during the time the switch is closed) is approximately Vb, Vs = (N+1)×Vb. Alternately the switch may get some of its control voltage or current directly from Vb and the rest from the induced Vs. Thus the switch-control voltage or current is "in phase" meaning that it keeps the switch closed, and it (via the switch) maintains the source voltage across the primary. In the case when there is little or no primary resistance and little or no switch resistance, the increase of the magnetizing current Im is a "linear ramp" defined by the formula in the first paragraph.
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In the cyclotron, in contrast, the particles encounter the accelerating voltage many times during their spiral path, and so are accelerated many times, so the output energy can be many times the accelerating voltage.
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These modules, while using the same physical layout, may differ in the specified voltage 1.5 or 1.35 volts. The lower voltage modules are sometimes, but not always, identified as DDR3L see also DDR3 SDRAM.
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Lowering the voltage applied increases the reliability and reduces the expected failure rate.Ch. Reynolds, AVX, Technical Information, Reliability Management of Tantalum Capacitors, PDF Applying a higher voltage than specified may destroy tantalum electrolytic capacitors.
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Direct current (DC) traction units use direct current drawn from a third rail, fourth rail, ground-level power supply or an overhead line. AC voltage is converted into DC voltage by using a rectifier.
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One of the inherent approximations in the "constant voltage" ratio method is that the ratio of the MPP voltage to V_{OC} is only approximately constant, so it leaves room for further possible optimization.
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Potassium voltage-gated channel subfamily C member 2 is a protein that in humans is encoded by the KCNC2 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit (Kv3.2).
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This component transforms the received voltage and frequency to the corresponding voltage, current and frequency to the laser source. Diode laser and fiber laser are the two most commonly used system for laser welding.
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Sylosis Live At High Voltage is Sylosis first live album that was released by High Voltage festival independently in 2011. It features the live set that the band played at the festival in its entirety.
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For hybrid polymer Al-e-caps a lower applied voltage in some cases can extend the lifetime. For polymer Ta-e-caps lowering the voltage applied increases the reliability and reduces the expected failure rate.
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The simulations included components with a voltage of 100 kV or higher. Typically lower-voltage components (e.g. 69 kV) can be ignored. Protection schemes were not considered in their effect on the bulk power system.
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Though not publicly documented, the protocol (e.g. voltage negotiations between device and charger) has been reverse-engineered.Hackster.io guide: Custom voltage from Qualcomm Quick Charge powerbank.Hackaday guide: “Unlocking 12V Quick Charge On A USB Power Bank”.
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A high-voltage cable for high-voltage direct current (HVDC) transmission has the same construction as the AC cable shown in figure 1. The physics and the test requirements are different.Kreuger 1991 Vol. 2, pp.
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This voltage is amplified, multiplexed, and converted to a digital signal.
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There is a large high voltage research center near Istra at .
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A low voltage current can stimulate the microbial degradation of PCBs.
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Azaspiracid is a phycotoxin that inhibits hERG voltage-gated potassium channels.
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Voltaj (, meaning voltage in Romanian) is a Romanian pop rock group.
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These low voltage connectors are rated at or below 1500 VDC.
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In the mid-20th century, voltage-regulator tubes were commonly used.
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Cn2 specifically targets the mammalian voltage-gated sodium channel (VGSC) Nav1.6.
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The simple resistor passive current source is ideal only when the voltage across it is zero; so voltage compensation by applying parallel negative feedback might be considered to improve the source. Operational amplifiers with feedback effectively work to minimise the voltage across their inputs. This results in making the inverting input a virtual ground, with the current running through the feedback, or load, and the passive current source. The input voltage source, the resistor, and the op-amp constitutes an "ideal" current source with value, .
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Rectifiers yield a unidirectional but pulsating direct current; half-wave rectifiers produce far more ripple than full-wave rectifiers, and much more filtering is needed to eliminate harmonics of the AC frequency from the output. Half-wave rectifier The no-load output DC voltage of an ideal half-wave rectifier for a sinusoidal input voltage is: where: : Vdc, Vav – the DC or average output voltage, : Vpeak, the peak value of the phase input voltages, : Vrms, the root mean square (RMS) value of output voltage.
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As t increases, the voltage goes above the breakdown voltage and secondary electron-hole pairs are produced by impact ionization. As long as the field in the avalanche region is maintained above the breakdown field, the electron-hole concentration grows exponentially with t. Similarly this concentration decays exponentially with time when the field is reduced below breakdown voltage during the negative swing of the AC voltage. The holes generated in the avalanche region disappear in the p+ region and are collected by the cathode.
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Potassium voltage-gated channel subfamily G member 1 is a protein that in humans is encoded by the KCNG1 gene. Voltage-gated potassium (Kv) channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. This gene encodes a member of the potassium channel, voltage- gated, subfamily G. This gene is abundantly expressed in skeletal muscle.
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A single common-emitter pnp-type transistor can operate correctly in saturation mode, with only ≈0,25 voltage drop, but also with impractically high base currents. A compound pnp- type transistor does not need as much drive current, but requires at least 1 V voltage drop. N-channel power MOSFET device enable the best possible combination of low drive current, very low dropout voltage and stability. However, low-dropout MOSFET operation requires an additional high-side voltage source (ΔU in schematic) for driving the gate.
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Voltage dependence in current and capacitance of a heterostructure barrier varactor The heterostructure barrier varactor (HBV) is a semiconductor device which shows a variable capacitance with voltage bias, similar to a varactor diode. Unlike a diode, it has an anti-symmetric current-voltage relationship and a symmetric capacitance-voltage relationship, as shown in the graph to the right. The device was invented by Erik Kollberg together with Anders Rydberg in 1989"Quantum-barrier-varactor diodes for high-efficiency millimetre-wave multipliers," Kollberg et. al, Electron. Lett.
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High Voltage is a double live album by British progressive rock band Emerson, Lake & Palmer, released in 2010. On 25 July 2010, Emerson, Lake and Palmer played a one-off 40th anniversary concert, headlining the High Voltage Festival event in Victoria Park, London. The entire concert was later released as the double-CD live album "High Voltage". With the deaths of Keith Emerson and Greg Lake in 2016, the High Voltage concert constitutes the final performance of Emerson, Lake and Palmer as a band.
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Fig. 1. Simplified transimpedance amplifier In electronics, a transimpedance amplifier (TIA) is a type of current-to-voltage converter, almost exclusively implemented with one or more operational amplifiers (op-amps). A TIA is used to amplifyElectronic Principles Paul E. Gray, Campbell Searle, pg. 641 the current output of Geiger–Müller tubes, photomultiplier tubes, accelerometers, photodetectors and other types of sensors to a usable voltage. Current-to- voltage converters are used with sensors that have a current response that is more linear than the voltage response.
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Unlike Zener diodes, these diodes keep the current constant instead of the voltage constant. These devices keep the current flowing through them unchanged when the voltage changes. Note that some devices are unidirectional and voltage across the device must have only one polarity for it to operate as a CLD, whereas other devices are bidirectional and can operate properly in either polarity. Wide- bandgap materials such as silicon carbide have been used in production devices to enable high-voltage applications in the kilovolt range.
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An Electromagnetic Log, sometimes called an "EM Log", measures the speed of a vessel through water. It operates on the principle that: 1 when a conductor (such as water) passes through an electromagnetic field, a voltage is created and 2 the amount of voltage created increases as the speed of the conductor increases. The process is # the EM Log creates an electromagnetic field. # a voltage is induced in the water; the magnitude of the voltage varies depending upon the speed of the water flow past the sensor.
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The Yamaha CS30/CS30L is an analog keyboard synthesizer that was released in 1977. It is the top of the range in Yamaha's original line-up of monophonic synthesizers, others in the range being the CS5, CS10 and CS15. It features two voltage controlled oscillators (VCOs), two voltage controlled filters (VCFs - both featuring low-pass, band-pass and high-pass options), two voltage controlled amplifiers (VCAs) and three envelope generators. It also sports a ring modulator and a voltage controlled low-frequency oscillator (LFO).
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MOSFET drain current vs. drain-to-source voltage for several values of the overdrive voltage, V_{GS}-V_{th}; the boundary between linear (ohmic) and saturation (active) modes is indicated by the upward curving parabola. In electronics, the relationship between the direct current (DC) through an electronic device and the DC voltage across its terminals is called a current–voltage characteristic of the device. Electronic engineers use these charts to determine basic parameters of a device and to model its behavior in an electrical circuit.
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The expression correctly predicts the output voltage if there is no current leaving port 2, but is increasingly inaccurate as the load increases. If, however, we attempt to use the circuit in reverse, driving it with a voltage at port 2 and calculate the resulting voltage at port 1 the expression gives completely the wrong result even with no load on port 1. It predicts a greater voltage at port 1 than was applied at port 2, an impossibility with a purely resistive circuit like this one.
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The most commonly used are Schottky diodes or p-n junctions. In the measurement process the steady-state diode reverse polarization voltage is disturbed by a voltage pulse. This voltage pulse reduces the electric field in the space charge region and allows free carriers from the semiconductor bulk to penetrate this region and recharge the defects causing their non- equilibrium charge state. After the pulse, when the voltage returns to its steady-state value, the defects start to emit trapped carriers due to the thermal emission process.
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However, lighting controllers and ballasts are responsible for generating high levels of harmonic distortion, which can be filtered with some types of voltage optimiser, in addition reducing the need for lighting controllers. A common concern is that some lighting will fail to strike at lower voltages. However, this should not occur since the aim of voltage optimisation is not simply to reduce the voltage as far as possible, but to bring it to the service level voltage at which it was designed to operate most efficiently.
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The processor line had models running at clock speeds from 1.0 GHz to 2.26 GHz . The models with lower frequencies were either low voltage or ultra-low voltage CPUs designed for improved battery life and reduced heat output. The 718 (1.3 GHz), 738 (1.4 GHz), and 758 (1.5 GHz) models are low-voltage (1.116 V) with a TDP of 10 W, while the 723 (1.0 GHz), 733 (1.1 GHz), and 753 (1.2 GHz) models are ultra-low voltage (0.940 V) with a TDP of 5 W.
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He also presented equations to model the noise introduced. Use of the term "voltage contrast" to describe the relationship between the voltage applied to a specimen and the resulting image contrast, is attributed to Everhart. As of 1959, Everhart produced the first voltage-contrast images of p-n junctions of biased silicon diodes. Voltage contrast, the ability to detect variations in surface electrical potentials on a specimen, is now one of several imaging modes used for the characterization, diagnosis and failure analysis of semiconductors.
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The LM317 is an adjustable analogue to the popular 78xx fixed regulators. Like the LM317, each of the 78xx regulators is designed to adjust the output voltage until it is some fixed voltage above the adjustment pin (which in this case is labelled "ground"). The mechanism used is similar enough that a voltage divider can be used in the same way as with the LM317 and the output follows the same formula, using the regulator's fixed voltage for Vref (e.g. 5 V for 7805).
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MOSFET-based digital circuits operate using voltages at circuit nodes to represent logical state. The voltage at these nodes switches between a high voltage and a low voltage during normal operation--when the inputs to a logic gate transition, the transistors making up that gate may toggle the gate's output. At each node in a circuit is a certain amount of capacitance. Capacitance can be thought of as a measure of how long it takes for a given current to produce a given voltage change.
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Miksa Déri (27 October 1854 November, Bács, Kingdom of Hungary, (now: Bač, Serbia) – 3 March 1938) was a Hungarian electrical engineer, inventor, power plant builder. He contributed with his partners Károly Zipernowsky and Ottó Bláthy, in the development of the closed iron core transformer and the ZBD model. His other important invention was the constant voltage AC electrical generator in the Ganz Works in 1883. The missing link of a full Voltage sensitive - voltage intensive (VSVI) system was the reliable AC Constant Voltage generator.
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The alpha subunit is a tetramer which forms the pore, the voltage sensor, and the calcium sensing region. This subunit of the channel is made up of seven trans-membrane units, and a large intracellular region. The voltage sensor is made by the S4 transmembrane region, which has several Arginine residues which act to ‘sense’ the changes in charge and move in a very similar way to other voltage gated potassium channels. As they move in response to the voltage changes they open and close the gate.
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Power Quality Analyzers, often referred to as Power Analyzers, make a digital recording of the voltage and current waveform (typically either one phase or three phase) and accurately calculate true power (watts), apparent power (VA) power factor, AC voltage, AC current, DC voltage, DC current, frequency, IEC61000-3-2/3-12 Harmonic measurement, IEC61000-3-3/3-11 flicker measurement, individual phase voltages in delta applications where there is no neutral line, total harmonic distortion, phase and amplitude of individual voltage or current harmonics, etc.
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In electrical engineering, modified nodal analysis or MNA is an extension of nodal analysis which not only determines the circuit's node voltages (as in classical nodal analysis), but also some branch currents. Modified nodal analysis was developed as a formalism to mitigate the difficulty of representing voltage-defined components in nodal analysis (e.g. voltage- controlled voltage sources). It is one such formalism.
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Two other high voltage power lines are under construction to evacuate power from Karuma: (a) The , 400kV Karuma–Olwiyo High Voltage Power Line, connects Karuma Power Station to a substation in Olwiyo, Nwoya District, for onward transmission to Pakwach, Nebbi, Paidha, Arua, Koboko, Yumbe and Moyo. and (b) The 132 kV Karuma–Lira High Voltage Power Line, which connects Karuma to Lira.
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All 30 locomotives owned by ČD Cargo were rebuilt to class 363.5 (dual voltage) by Škoda. ZSSK announced tender for rebuilding 15 locomotives class 163/162 to class 361, which was won by ŽOS Vrútky. As of January, 2014, 5 locomotives of class 361 (dual voltage, max. speed 140 km/h) and 4 locomotives of class 361.1 (dual voltage, max.
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The breakdown starts when reverse voltage is applied. In the case of Zener breakdown, it starts at a particular voltage. In this diode the voltage remains relatively constant (independent of current) when it is connected in reverse bias. The backward diode is a special form of tunnel diode in which the tunneling phenomenon is only incipient, and the negative resistance region virtually disappears.
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A graph plotting voltage over time, after the application of a charge It has been noticed that after the EDLC experiences a charge or discharge, the voltage will drift over time, relaxing toward its previous voltage level. The observed relaxation can occur over several hours and is likely due to long diffusion time constants of the porous electrodes within the EDLC.
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Figure 4 - TRV in inductive circuit A terminal fault is a fault that occurs at the circuit breaker terminals. The circuit breaker interrupts a short-circuit at current zero, at this instant the supply voltage is maximum and the recovery voltage tends to reach the supply voltage with a high frequency transient. The normalized value of the overshoot or amplitude factor is 1.4.
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In 2011, Lu et al., reported reversible electrochemical activity in the porous niobate KNb5O13. This material inserted approximately 3.5Li per formula unit (about 125 mAh/g) at a voltage near 1.3V (vs Li). This lower voltage (compared to titantes) is useful in systems where higher energy density is desirable without significant SEI formation as it operates above the typical electrolyte breakdown voltage.
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Six sets of 160 solar cells were mounted on aluminium plates around the surface, providing 17 volts. Within the sphere, a vertically aligned cylinder housed the batteries and voltage regulators. A stable voltage was essential for accurate transponder operation, and, in addition to the voltage regulators, each battery cell in the battery was matched to within 0.03 volts in their discharge curves.
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Small current at UME enables electrochemical measurements in low conductive media (organic solvents), where voltage drop associated with high solution resistance makes these experiments difficult for conventional electrodes. Furthermore, small voltage drop at UME leads to a very small voltage distortion at the electrode- solution interface which allows using two-electrode setup in voltammetric experiment instead of conventional three-electrode setup.
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During a fault on the transmission line the fault current increases and the voltage at the fault point decreases. The V/I ratio is measured at the location of CTs and PTs. The voltage at the PT location depends on the distance between the PT and the fault. If the measured voltage is lesser, that means the fault is nearer and vice versa.
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The abbreviation for the genes encoding for voltage-gated sodium channel starts with three letters: SCN. In contrast to these sodium channels, ENaC is constitutively active and is not voltage-dependent. The second N in the abbreviation (SCNN1D) represents that these are NON-voltage-gated channels. In most vertebrates, sodium ions are the major determinant of the osmolarity of the extracellular fluid.
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FAM control of induction motor torque has two types of control namely current control and voltage control. Constant exciting current produces good linearity's between torque and slip frequency. In current control, the primary current is the control input to the induction motor whereas the primary terminal voltage is the control input in voltage control. Two transient phenomena are associated with induction motor operation.
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Kerite products include high voltage and specialty cable for applications such as underwater use and areas with high ground water levels. High voltage cable is Kerite’s flagship product, made for voltages ranging from 46kV through 138kV. This cable is used for power transmission applications. Specialty cable includes medium and high voltage cable for subsea installations such as the Panama Canal.
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The current–voltage graph of an ohmic device consists of a straight line through the origin with positive slope. Other components and materials used in electronics do not obey Ohm's law; the current is not proportional to the voltage, so the resistance varies with the voltage and current through them. These are called nonlinear or nonohmic. Examples include diodes and fluorescent lamps.
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Electrogenic microorganisms consuming an energy source (such as acetic acid) release electrons and protons, creating an electrical potential of up to 0.3 volts. In a conventional MFC, this voltage is used to generate electrical power. In a MEC, an additional voltage is supplied to the cell from an outside source. The combined voltage is sufficient to reduce protons, producing hydrogen gas.
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Overhead distribution line in Lamma Island kWh meters in Hong Kong Electricity is distributed at 22 kV and 11 kV voltage level to over 3,800 distribution substations on HEC side. CLP distributes power mainly at 11 kV level. Voltage is further stepped down to 380 V three-phase or 220 V single-phase and supplied through low voltage cables to customers.
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An externally triggered, 3.5 microsecond flash. The flash fully discharges before the arc can move away from the glass and fill the tube, causing excessive wear to the lamp. Simmer-voltage triggering is the least common method. In this technique, the capacitor voltage is not initially applied to the electrodes, but instead, a high voltage spark streamer is maintained between the electrodes.
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The low voltage subsystem includes mentioned above controller unit, internal and external lights, door gear and two accumulator batteries. Due to differentiating voltage levels the hazard of electric shock to driver and passengers was reduced greatly. All electric devices inside passengers' saloon and driver cabin are supplied only with safe 24V voltage. Power 550V circuits are placed under the floor.
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VSPs have been used as an tool to manipulate phospholipids in experimental settings. Because membrane potential can be controlled using patch clamp techniques, placing VSPs in a membrane allows for experimenters to rapidly dephosphorylate substrates of VSPs. VSPs' voltage sensors have also been used to engineer genetically encodable voltage sensitive fluorescent probes. These probes allow experimenters to visualize voltage in membranes using fluorescence.
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External fields create a voltage across the inductance of the outside of the outer conductor between sender and receiver. The effect is less when there are several parallel cables, as this reduces the inductance and, therefore, the voltage. Because the outer conductor carries the reference potential for the signal on the inner conductor, the receiving circuit measures the wrong voltage.
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LVD versions of SCSI allow less than 25 m cable length not because of the lower voltage, but because these SCSI standards allow much higher speeds than the older HVD SCSI. The generic term high-voltage differential signaling describes a variety of systems. Low- voltage differential signaling or LVDS, on the other hand, is a specific system defined by a TIA/EIA standard.
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A purely analytical calculation of Pst is almost impossible. In the standardIEC 61000-3-3, Limits – Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems, for equipment with rated current ≤16 A per phase and not subject to conditional connection, Edition 2.0, 2008-06 there are formulas which allow the estimation of the Pst values to be expected.
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Each mesh produces one equation. These equations are the sum of the voltage drops in a complete loop of the mesh current. For problems more general than those including current and voltage sources, the voltage drops will be the impedance of the electronic component multiplied by the mesh current in that loop.Puckett, Russell E., & Romanowitz, Harry A. (1976). Introduction to Electronics (2nd ed.).
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This minimum voltage is dictated by the need to keep the output transistor of the mirror in active mode. The range of voltages where the mirror works is called the compliance range and the voltage marking the boundary between good and bad behavior is called the compliance voltage. There are also a number of secondary performance issues with mirrors, for example, temperature stability.
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Ions can be created in an electric glow discharge. A glow discharge is a plasma formed by the passage of electric current through a low-pressure gas. It is created by applying a voltage between two metal electrodes in an evacuated chamber containing gas. When the voltage exceeds a certain value, called the striking voltage, the gas forms a plasma.
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Magneto ignition was introduced on the 1899 Daimler Phönix. This was followed by Benz, Mors, Turcat-Mery, and Nesseldorf, and soon was used on most cars up until about 1918 in both low voltage (voltage for secondary coils to fire the spark plugs) and high voltage magnetos (to fire the spark plug directly, similar to coil ignitions, introduced by Bosch in 1903).
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Charge-transfer amplifier schematic The charge-transfer amplifier (CTA) is an electronic amplifier circuit. Also known as transconveyance amplifiers, CTAs amplify electronic signals by dynamically conveying charge between capacitive nodes in proportion to the size of a differential input voltage. By appropriately selecting the relative node capacitances, voltage amplification occurs by the charge-voltage relationship of capacitors. CTAs are clocked, or sampling, amplifiers.
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The abbreviation for the genes encoding for voltage-gated sodium channel starts with three letters: SCN. In contrast to these sodium channels, ENaC is constitutively active and is not voltage-dependent. The second N in the abbreviation (SCNN1A) represents that these are NON-voltage-gated channels. In most vertebrates, sodium ions are the major determinant of the osmolarity of the extracellular fluid.
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A transformer steps up the output of the system's amplifier to the distribution voltage. At the distant loudspeaker locations, a step-down transformer matches the speaker to the rated voltage of the line, so the speaker produces rated nominal output when the line is at nominal voltage. Loudspeaker transformers commonly have multiple primary taps to adjust the volume at each speaker in steps.
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The abbreviation for the genes encoding for voltage-gated sodium channel starts with three letters: SCN. In contrast to these sodium channels, ENaC is constitutively active and is not voltage-dependent. The second N in the abbreviation (SCNN1A) represents that these are NON-voltage-gated channels. In most vertebrates, sodium ions are the major determinant of the osmolarity of the extracellular fluid.
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The abbreviation for the genes encoding for voltage-gated sodium channel starts with three letters: SCN. In contrast to these sodium channels, ENaC is constitutively active and is not voltage-dependent. The second N in the abbreviation (SCNN1) represents that these are NON-voltage-gated channels. In most vertebrates, sodium ions are the major determinant of the osmolarity of the extracellular fluid.
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A low-voltage electron microscope (LVEM) is operated at relatively low electron accelerating voltage between 5–25 kV. Some of these can be a combination of SEM, TEM and STEM in a single compact instrument. Low voltage increases image contrast which is especially important for biological specimens. This increase in contrast significantly reduces, or even eliminates the need to stain.
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A standard cooling fan is essentially a bladed DC motor. By varying the voltage input across the acceptable range for a fan, the speed of the fan will increase (to added voltage) and decrease (to reduced voltage); a faster fan means more air moved and thus a higher heat exchange rate. There are a few ways to perform this regulation, as described below.
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Lecher and early researchers used long thin Geissler tubes, laying the glass tube directly across the line. The high voltage of early transmitters excited a glow discharge in the gas. In modern times small neon bulbs are often used. One problem with using glow discharge bulbs is their high striking voltage makes it difficult to localize the exact voltage minimum.
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Two digital voltmeters. Note the 40 microvolt difference between the two measurements, an offset of 34 parts per million. A digital voltmeter (DVM) measures an unknown input voltage by converting the voltage to a digital value and then displays the voltage in numeric form. DVMs are usually designed around a special type of analog-to-digital converter called an integrating converter.
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In a flat sheet of insulator between two flat metal electrodes, the electric field E is proportional to the voltage difference V divided by the thickness D of the insulator, E \propto V/D, so in general the breakdown voltage is proportional to the length of insulation between two conductors. However the shape of the conductors can influence the breakdown voltage.
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Transfer function of a Schmitt trigger. The horizontal and vertical axes are input voltage and output voltage, respectively. T and −T are the switching thresholds, and M and −M are the output voltage levels. In electronics, a Schmitt trigger is a comparator circuit with hysteresis implemented by applying positive feedback to the noninverting input of a comparator or differential amplifier.
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Conversely, when the output current is (near) zero, the voltage at the load is higher. This follows from Ohm's law. Rather than increasing output voltage at high current to try to maintain the same load voltage, droop instead simply allows this drop to take place and designs around it. The behaviour of the system with and without droop is as follows: Image:Droop behaviour.
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A 3-stage discrete component vector inversion generator. A vector inversion generator (VIG) is an electric pulse compression and voltage multiplication device, allowing shaping a slower, lower voltage pulse to a narrower, higher- voltage one. VIGs are used in military technology, e.g. some directed-energy weapons, as a secondary stage of another pulsed power source, commonly an explosive-driven ferroelectric generator.
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Graph showing a voltage with a leading and lagging current, plotted against time. Leading and lagging current are phenomena that occur as a result of alternating current. In a circuit with alternating current, the value of voltage and current vary sinusoidally. In this type of circuit, the terms lead, lag, and in phase are used to describe current with reference to voltage.
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By contrast the very latest Russian manufactured tubes (2012) not only carry the same internal electrode structure as the original KT66 (they now look the same) they also have the same rugged electrical characteristics and can withstand a high voltage on grid 2 comparable to the anode voltage rating, allowing greater power output afforded by higher voltage capability when run in ultralinear connection.
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Dielectrophoresis uses a high frequency alternating current, unlike electrophoresis in which a direct current is applied. Once the cells are brought together, a pulsed voltage is applied. The pulse voltage causes the cell membrane to permeate and subsequent combining of the membranes and the cells then fuse. After this, alternative voltage is applied for a brief period of time to stabilize the process.
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The cutoff transistor breaks the connection between its input and output. As a result, its input voltage does not affect the output voltage. The input resistance is high again since the base-emitter junction is cutoff.
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Calcium channel, voltage-dependent, L type, alpha 1C subunit (also known as Cav1.2) is a protein that in humans is encoded by the CACNA1C gene. Cav1.2 is a subunit of L-type voltage-dependent calcium channel.
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The common-mode input voltage can vary between the two supply rails but cannot closely reach them since some voltage drops (minimum 1 volt) have to remain across the output transistors of the two current mirrors.
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The cascode circuit requires two transistors and requires a relatively high supply voltage. For the two-FET cascode, both transistors must be biased with ample VDS in operation, imposing a lower limit on the supply voltage.
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The two output terminals can be defined at the active devices and have complementary states. One has high voltage while the other has low voltage, except during the brief transitions from one state to the other.
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Sometimes the cords used to plug in dual voltage 120 V / 240 V equipment are rated only for 125 V, so care must be taken by travellers to use only cords with an appropriate voltage rating.
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V multiplier (inside grey box) used in push-pull amplifier biasing In electronics, a rubber diode or V multiplier is a bipolar junction transistor circuit that serves as a voltage reference. It consists of one transistor and two resistors, and the reference voltage across the circuit is determined by the selected resistor values and the base-to-emitter voltage (V) of the transistor. The circuit behaves as a voltage divider, but with the voltage across the base-emitter resistor determined by the forward base-emitter junction voltage. It is commonly used in the biasing of push-pull output stages of amplifiers, where one benefit is thermal compensation: The temperature-dependent variations in the multiplier's V, approximately -2.2 mV/ºC, can be made to match variations occurring in the V of the power transistors by mounting to the same heat sink.
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250px The voltage drop VF across the forward biased diode in the circuit of a passive rectifier is undesired. In this active version, the problem is solved by connecting the diode in the negative feedback loop. The op-amp compares the output voltage across the load with the input voltage and increases its own output voltage with the value of VF. As a result, the voltage drop VF is compensated and the circuit behaves very nearly as an ideal (super) diode with VF = 0 V. The circuit has speed limitations at high frequency because of the slow negative feedback and due to the low slew rate of many non-ideal op-amps.
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Impedance begins to grow at around 100 kHz and reaches 10 Ohm at around 10 MHz. Regulation of voltages higher than 2.5 V requires an external voltage divider R2R1; cathode voltage and output impedance increase 1+R2/R1 times. Maximum sustained regulated voltage may not exceed 36 V, maximum cathode-anode voltage is limited to 37 V. Historically, TL431 was designed and manufactured with this application in mind, and was advertised as an "extremely attractive replacement for high cost, temperature-compensated zeners".. Adding an emitter follower converts a shunt regulator into a series regulator. Efficiency is mediocre at best, because single npn-type transistors or Darlington pairs require fairly high collector-emitter voltage drop.
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The basic principle of dynamic voltage restoration is to inject a voltage of the magnitude and frequency necessary to restore the load side voltage to the desired amplitude and waveform, even when the source voltage is unbalanced or distorted. Generally, devices for dynamic voltage restoration employ gate turn off thyristors, (GTO) solid state power electronic switches in a pulse-width modulated (PWM) inverter structure. The DVR can generate or absorb independently controllable real and reactive power at the load side. In other words, the DVR is a solid state DC to AC switching power converter that injects a set of three-phase AC output voltages in series and synchronicity with the distribution and transmission line voltages.
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Until about 1880, the paradigm for AC power transmission from a high voltage supply to a low voltage load was a series circuit. Open-core transformers with a ratio near 1:1 were connected with their primaries in series to allow use of a high voltage for transmission while presenting a low voltage to the lamps. The inherent flaw in this method was that turning off a single lamp (or other electric device) affected the voltage supplied to all others on the same circuit. Many adjustable transformer designs were introduced to compensate for this problematic characteristic of the series circuit, including those employing methods of adjusting the core or bypassing the magnetic flux around part of a coil.
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Because power consumption increases with speed, the reduced voltage allows higher speed operation without unreasonable power and cooling requirements. DDR4 operates at a voltage 1.2 V with a frequency between 800 and 1600 MHz (DDR4-1600 through DDR4-3200), compared to frequencies between 400 and 1067 MHz (DDR3-800 through DDR3-2133) and voltage requirements of 1.5 V of DDR3. Due to the nature of DDR, speeds are typically advertised as doubles of these numbers (DDR3-1600 and DDR4-2400 are common, with DDR4-3200, DDR4-4800 and DDR4-5000 available at high cost). Unlike DDR3's 1.35 V low voltage standard DDR3L, there is no DDR4L low voltage version of DDR4..
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Voltage-gated ion channels, also known as voltage dependent ion channels, are channels whose permeability is influenced by the membrane potential. They form another very large group, with each member having a particular ion selectivity and a particular voltage dependence. Many are also time-dependent—in other words, they do not respond immediately to a voltage change but only after a delay. One of the most important members of this group is a type of voltage-gated sodium channel that underlies action potentials—these are sometimes called Hodgkin-Huxley sodium channels because they were initially characterized by Alan Lloyd Hodgkin and Andrew Huxley in their Nobel Prize-winning studies of the physiology of the action potential.
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CMOS circuits are constructed in such a way that all P-type metal–oxide–semiconductor (PMOS) transistors must have either an input from the voltage source or from another PMOS transistor. Similarly, all NMOS transistors must have either an input from ground or from another NMOS transistor. The composition of a PMOS transistor creates low resistance between its source and drain contacts when a low gate voltage is applied and high resistance when a high gate voltage is applied. On the other hand, the composition of an NMOS transistor creates high resistance between source and drain when a low gate voltage is applied and low resistance when a high gate voltage is applied.
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For either enhancement- or depletion-mode devices, at drain-to-source voltages much less than gate-to- source voltages, changing the gate voltage will alter the channel resistance, and drain current will be proportional to drain voltage (referenced to source voltage). In this mode the FET operates like a variable resistor and the FET is said to be operating in a linear mode or ohmic mode. If drain-to-source voltage is increased, this creates a significant asymmetrical change in the shape of the channel due to a gradient of voltage potential from source to drain. The shape of the inversion region becomes "pinched-off" near the drain end of the channel.
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All equipment placed on the market within the E.U. since voltage harmonisation in 1995 should operate satisfactorily at voltages within the range 230 V +/-10%. Equipment rated at 220 V should operate satisfactorily down to 200 V. By efficiently bringing supply voltages to the lower end of the statutory voltage range, voltage optimisation technology could yield average energy savings of around 13% . The higher the voltage the higher the power consumption in the case of a pure resistance load. A reduction in voltage does not affect the energy used by the domestic appliances which use resistive loads except in devices such as kettles and toasters which will take longer to do their job due to atmospheric losses.
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Voltage across the primary coil results in a proportional voltage being induced across the secondary winding of the coil. The turns ratio between the primary and secondary coil is selected so that the voltage across the secondary reaches a very high value, enough to arc across the gap of the spark plug. As the voltage of the primary winding rises to several hundred volts, the voltage on the secondary winding rises to several tens of thousands of volts, since the secondary winding typically has 100 times as many turns as the primary winding. The capacitor and the coil together form a resonant circuit which allows the energy to oscillate from the capacitor to the coil and back again.
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NE-2 neon lamp A neon bulb, often used as an indicator lamp in appliances, consists of a glass bulb containing two electrodes, separated by an inert gas such as neon at low pressure. Its nonlinear current- voltage characteristics (diagram below) allow it to function as a switching device. When a voltage is applied across the electrodes, the gas conducts almost no electric current until a threshold voltage is reached (point b), called the firing or breakdown voltage, Vb.Dance, 1967, p.6-7 At this voltage electrons in the gas are accelerated to a high enough speed to knock other electrons off gas atoms, which go on to knock off more electrons in a chain reaction.
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The very small capacitance between overhead lines and a fluorescent lamp tube (in the foreground of the photo) provides enough current to cause the lamp to glow. Ungrounded metal objects close to electric field sources such as neon signs or conductors carrying alternating currents can have measurable voltage levels caused by capacitive coupling. Since voltages detected by high-impedance instruments disappear or become greatly reduced when a low impedance is substituted, the effect is sometimes called phantom voltage (or ghost voltage).Phantom voltage is also a term used in audio engineering, where a voltage is intentionally applied between the ground wire and both wires of a balanced audio line, to provide power for a microphone or other device.
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An integrating ADC is a type of analog-to-digital converter that converts an unknown input voltage into a digital representation through the use of an integrator. In its basic implementation, the dual-slope converter, the unknown input voltage is applied to the input of the integrator and allowed to ramp for a fixed time period (the run-up period). Then a known reference voltage of opposite polarity is applied to the integrator and is allowed to ramp until the integrator output returns to zero (the run-down period). The input voltage is computed as a function of the reference voltage, the constant run-up time period, and the measured run-down time period.
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In low voltage converters (around 10 volts and less), the voltage drop of a diode (typically around 0.7 to 1 volt for a silicon diode at its rated current) has an adverse effect on efficiency. One classic solution replaces standard silicon diodes with Schottky diodes, which exhibit very low voltage drops (as low as 0.3 volts). However, even Schottky rectifiers can be significantly more lossy than the synchronous type, notably at high currents and low voltages. When addressing very low-voltage converters, such as a buck converter power supply for a computer CPU (with a voltage output around 1 volt, and many amperes of output current), Schottky rectification does not provide adequate efficiency.
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Schmitt trigger implemented by two emitter-coupled transistor stages The original Schmitt trigger is based on the dynamic threshold idea that is implemented by a voltage divider with a switchable upper leg (the collector resistors RC1 and RC2) and a steady lower leg (RE). Q1 acts as a comparator with a differential input (Q1 base-emitter junction) consisting of an inverting (Q1 base) and a non-inverting (Q1 emitter) inputs. The input voltage is applied to the inverting input; the output voltage of the voltage divider is applied to the non-inverting input thus determining its threshold. The comparator output drives the second common collector stage Q2 (an emitter follower) through the voltage divider R1-R2.
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A sufficiently negative voltage on the grid (usually around 3-5 volts in small tubes such as the 6AV6, but as much as –130 volts in early audio power devices such as the '45), will prevent any electrons from getting through to the anode, turning off the anode current. This is called the "cutoff voltage". Since below cutoff the anode current ceases to respond to the grid voltage, the voltage on the grid must remain above the cutoff voltage for faithful (linear) amplification. The triode is similar in operation to the n-channel JFET; it is normally on, and exhibits progressively lower and lower plate current as the grid/gate is pulled increasingly negative relative to the source/cathode.
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Development and type tests of HVDC ±250 MIsubmarine cable system, Tae-ho Lee et al, Proceedings of the 16th International Symposium on High Voltage Engineering. Two of the high-voltage cables are normally used as the respective high-voltage conductors for the two converter poles and the medium- voltage cable is normally used as the neutral return conductor, but the third high-voltage cable is capable of being connected in parallel with, or instead of, any of the other three cables, giving a large number of possible operating modes.Project Overview , LS Cable and System. The converter stations use Line- Commutated Converters with a conventional arrangement of a single Twelve-pulse bridge per pole.
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Brune test for connecting two-port networks in series. To check if two two-port networks can be connected in a series-series configuration, first of all just the input ports are connected in series, a voltage is applied to the input and the open-circuit voltage is measured/calculated between the output terminals to be connected. If there is a voltage drop, the two-port networks cannot be combined in series. The same test is repeated from the output side of the two-port networks (series connection of the output ports, application of a voltage to the output, measurement/calculation of the open-circuit voltage between the input terminals to be connected).
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Brune test for connecting two-port networks in parallel. To check if two two-port networks can be connected in a parallel- parallel configuration, first of all just the input ports are connected in parallel, a voltage is applied to the input and the open-circuit voltage is measured/calculated between the outputs that are short-circuited each. If there is a voltage drop, the two-port networks cannot be combined in parallel. The same test is repeated from the output side of the two-port networks (parallel connection of the output ports, application of a voltage to the output, measurement/calculation of the open-circuit voltage between the inputs that are short-circuited each).
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Now let us look at the internal working of this meter. Voltage drop across an inductor is directly proportion to frequency of the source voltage, as we increase the frequency of the applied voltage the voltage drop across the inductor L1 increase that means the voltage impressed between the coil 1 is increased hence the current through the coil 1 increase while the current through the coil 2 decreases. Since the current through the coil 1 increases the magnetic field also increases and the magnetic needle attracts more towards the left side showing the increment in the frequency. Similar action will takes if decrease the frequency but in this the pointer will moves towards the left side. richardsradios.co.
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An integrating ADC (also dual-slope or multi-slope ADC) applies the unknown input voltage to the input of an integrator and allows the voltage to ramp for a fixed time period (the run-up period). Then a known reference voltage of opposite polarity is applied to the integrator and is allowed to ramp until the integrator output returns to zero (the run-down period). The input voltage is computed as a function of the reference voltage, the constant run-up time period, and the measured run-down time period. The run-down time measurement is usually made in units of the converter's clock, so longer integration times allow for higher resolutions.
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Their mechanism of action includes blockade of glutamate-gated ion channels, voltage-gated sodium channels, or voltage-dependent calcium channels. Agatoxin is named after the funnel web spider (Agelenopsis aperta) which produces a venom containing several agatoxins.
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Unity gain here implies a voltage gain of one (i.e. 0 dB), but significant current gain is expected. In this configuration, the entire output voltage (β = 1 in Fig. 2) is fed back into the inverting input.
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High voltage e-cigarettes are capable of producing large amounts of carbonyls. Reduced voltage (3.0 V) e-cigarettes had e-cigarette aerosol levels of formaldehyde and acetaldehyde roughly 13 and 807-fold less than with cigarette smoke.
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Nidec Industrial Solutions manufactures a complete electrical package including Medium Voltage electric motors and generators, Low and Medium voltage drives, Power electronics for Power Supply and Power Quality and develops control and automation systems with proprietary platform.
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Kirchhoff's loop rule states that the sum of the voltage drops in a closed loop around a circuit equals zero. This comes from the conservation of energy, as voltage is defined as the energy per unit charge.
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Potassium voltage-gated channel subfamily A member 6 also known as Kv1.6 is a protein that in humans is encoded by the KCNA6 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
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Potassium voltage-gated channel subfamily A member 10 also known as Kv1.8 is a protein that in humans is encoded by the KCNA10 gene. The protein encoded by this gene is a voltage-gated potassium channel subunit.
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By introducing a salinity gradient and allowing some of the ions to diffuse out of the capacitor, this reduces the capacitance, and so the voltage must increase, since the voltage equals the ratio of charge to capacitance.
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A disadvantage of this method is the need to break the circuit to introduce the shunt. Another problem is measuring the voltage across the shunt when common-mode voltages are present; a differential voltage measurement is needed.
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A negative biased clamp A negative biased voltage clamp is likewise identical to an equivalent unbiased clamp but with the output voltage offset in the negative direction by the bias amount VBIAS. Thus, VOUT = VIN − (VINpeak \+ VBIAS).
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Feedback-controlled electromigration (FCE) is an experimental technique to investigate the phenomenon known as electromigration. By controlling the voltage applied as the conductance varies it is possible to keep the voltage at a critical level for electromigration.
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Having high PSRR over a wide band allows the LDO to reject high-frequency noise like that arising from a switcher. Similar to other specifications, PSRR fluctuates over frequency, temperature, current, output voltage, and the voltage differential.
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The voltage was adjusted with the potentiometer until the sound was loudest in the earphone. The bias moved the operating point to the curved "knee" of the device's current–voltage curve, which produced the largest rectified current.
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A higher threshold voltage also reduces the leakage current of a path.
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Voltage Pictures handled international distribution rights at the 2015 Berlin Film Festival.
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The current-voltage curve of a nonohmic device is a curved line.
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Device modules include thermostats, audible alarms and controllers for low voltage switches.
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They require special techniques for jointing and terminating, see High-voltage cable.
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They also opened the 2010 High Voltage Festival in Victoria Park, London.
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These extra-low voltage connectors are rated at or below 120 VDC.
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NPFF receptors are also coupled to voltage-gated N-type Ca2+ channels.
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The general negative feedback arrangement can be implemented by an IC voltage regulator (LM317 voltage regulator on Figure 8). As with the bare emitter follower and the precise op-amp follower above, it keeps up a constant voltage drop (1.25 V) across a constant resistor (1.25 Ω); so, a constant current (1 A) flows through the resistor and the load. The LED is on when the voltage across the load exceeds 1.8 V (the indicator circuit introduces some error). The grounded load is an important advantage of this solution.
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When both electrodes have approximately the same resistance (internal resistance), the potential of the capacitor decreases symmetrically over both double-layers, whereby a voltage drop across the equivalent series resistance (ESR) of the electrolyte is achieved. For asymmetrical supercapacitors like hybrid capacitors the voltage drop between the electrodes could be asymmetrical. The maximum potential across the capacitor (the maximal voltage) is limited by the electrolyte decomposition voltage. Both electrostatic and electrochemical energy storage in supercapacitors are linear with respect to the stored charge, just as in conventional capacitors.
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The dielectric is used in very thin layers and so absolute breakdown voltage of capacitors is limited. Typical ratings for capacitors used for general electronics applications range from a few volts to 1 kV. As the voltage increases, the dielectric must be thicker, making high- voltage capacitors larger per capacitance than those rated for lower voltages. The breakdown voltage is critically affected by factors such as the geometry of the capacitor conductive parts; sharp edges or points increase the electric field strength at that point and can lead to a local breakdown.
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In this arrangement, a fraction of a known voltage from a resistive slide wire is compared with an unknown voltage by means of a galvanometer. The sliding contact or wiper of the potentiometer is adjusted and the galvanometer briefly connected between the sliding contact and the unknown voltage. The deflection of the galvanometer is observed and the sliding tap adjusted until the galvanometer no longer deflects from zero. At that point the galvanometer draws no current from the unknown source, and the magnitude of voltage can be calculated from the position of the sliding contact.
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If the tube voltage is progressively increased from zero the efficiency of detection will rise until the most energetic radiation starts to produce pulses which can be detected by the electronics. This is the "starting voltage". Increasing the voltage still further results in rapidly rising counts until the "knee" or threshold of the plateau is reached, where the rate of increase of counts falls off. This is where the tube voltage is sufficient to allow a complete discharge along the anode for each detected radiation count, and the effect of different radiation energies are equal.
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Layout example of a Kelvin connection When a Kelvin connection is used, current is supplied via a pair of force connections (current leads). These generate a voltage drop across the impedance to be measured according to Ohm's law V=IR. A pair of sense connections (voltage leads) are made immediately adjacent to the target impedance, so that they do not include the voltage drop in the force leads or contacts. Since almost no current flows to the measuring instrument, the voltage drop in the sense leads is negligible.
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Software in the DSP continually monitors and adjusts this generated voltage to produce a balanced three-phase output at all times. It also provides protective functions by shutting down in case of utility over-voltage and under-voltage or a fault. With the ability to adjust to changing conditions and maintain voltage balance, a digital phase converter can safely and efficiently operate virtually any type of three-phase equipment or any number of multiple loads. The solid-state design results in a relatively small package with no moving parts except for small cooling fans.
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The generator voltage for modern utility-connected generators ranges from in smaller units to in larger units. The generator high-voltage leads are normally large aluminium channels because of their high current as compared to the cables used in smaller machines. They are enclosed in well-grounded aluminium bus ducts and are supported on suitable insulators. The generator high-voltage leads are connected to step-up transformers for connecting to a high-voltage electrical substation (usually in the range of 115 kV to 765 kV) for further transmission by the local power grid.
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Also known as the let-through voltage, this specifies what spike voltage will cause the protective components inside a surge protector to short or clamp. A lower clamping voltage indicates better protection, but can sometimes result in a shorter life expectancy for the overall protective system. The lowest three levels of protection defined in the UL rating are 330 V, 400 V and 500 V. The standard let-through voltage for 120 V AC devices is 330 volts. Underwriters Laboratories (UL), a global independent safety science company, defines how a protector may be used safely.
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BDS-1 modifies the voltage-dependent gating properties of Kv3 potassium channels by binding to the voltage sensitive domains on S3b and S4 subunits. The toxin elicits a depolarizing shift in the conductance-voltage relation, making it more difficult to open, and slows both the activation and inactivation kinetics of these ion channels. In addition, BDS-1 enhances the current flowing through several voltage-gated sodium channels. The toxin binds to the S3-S4 linker of domain IV and slows the inactivation of the channel, resulting in increased current upon depolarization.
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However, once a stimulus activates the voltage-gated sodium channels to open, positive sodium ions flood into the cell and the voltage increases. This process can also be initiated by ligand or neurotransmitter binding to a ligand-gated channel. More sodium is outside the cell relative to the inside, and the positive charge within the cell propels the outflow of potassium ions through delayed-rectifier voltage-gated potassium channels. Since the potassium channels within the cell membrane are delayed, any further entrance of sodium activates more and more voltage-gated sodium channels.
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Fig 1: Schematic of the split-pi converter topology In electronics, a split-pi topology is a pattern of component interconnections used in a kind of power converter that can theoretically produce an arbitrary output voltage, either higher or lower than the input voltage. In practice the upper voltage output is limited to the voltage rating of components used. It is essentially a boost (step-up) converter followed by a buck (step-down) converter. The topology and use of MOSFETs make it inherently bi-directional which lends itself to applications requiring regenerative braking.
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There is almost no voltage drop in this bus bar. The output signal, proportional to the ampere turns in the control current bus bar, is derived from the alternating excitation voltage of the magnetic amplifier, there is no voltage created or induced on the bus bar. The output signal has only a magnetic connection with the bus bar so the bus may be, quite safely, at any (EHT) voltage with respect to the instrumentation. Instrumentation magnetic amplifiers are commonly found on space craft where a clean electromagnetic environment is highly desirable.
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The exhaust fumes pass the oxygen sensor. The content of oxygen in the exhaust fumes is measured through a chemical reaction, this results in an output voltage. If the engine runs rich (Lambda lower than 1) the output voltage would be more than 0.45 V and if the engine runs lean (Lambda higher than 1) the output voltage would be less than 0.45 V. The output voltage swings about 0.45 V when Lambda passes 1. The ECU continuously corrects the injection duration so that Lambda=1 is always met.
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However, the incremental conductance method can produce oscillations (unintentionally) and can perform erratically under rapidly changing atmospheric conditions. The sampling frequency is decreased due to the higher complexity of the algorithm compared to the P&O; method. In the constant voltage ratio (or "open voltage") method, the current from the photovoltaic array must be set to zero momentarily to measure the open circuit voltage and then afterwards set to a predetermined percentage of the measured voltage, usually around 76%. Energy may be wasted during the time the current is set to zero.
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A. Albertsen, Jianghai Europe, Keep your distance – Voltage Proof of Electrolytic Capacitors, PDFI.Horacek, T.Zednicek, S.Zednicek, T.Karnik, J.Petrzilek, P.Jacisko, P.Gregorova, AVX, High CV Tantalum Capacitors - Challenges and Limitations The large surface compared to a smooth one is the second reason for the relatively high capacitance values of electrolytic capacitors compared with other capacitor families. Because the forming voltage defines the oxide layer thickness, the desired voltage rating can be produced very simply. Electrolytic capacitors have high volumetric efficiency, the so- called "CV product", defined as the product of capacitance and voltage divided by volume.
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In an MCS the positive difference between the voltage of regulation element and conduction voltage drop of MOSFET is applied to location between the collector region and emitter region of the pnp transistor. Hole concentration is accumulated at emitter side in n-base layer because of impossibility of the hole flow through forward bias collector-base junction of the pnp transistor. Carrier distribution in n-base is similar to that of saturation bipolar transistor and low saturation voltage of MCS, even at high voltage ratings, can be achieved.
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For low voltage work (for example, in automobiles), the lamp used is usually a small, low-voltage incandescent light bulb. These lamps usually are designed to operate on approximately 12 V; application of an automotive test lamp on mains voltage will destroy the lamp and may cause a short-circuit fault in the tester. For line voltage (mains) work, the lamp is usually a small neon lamp connected in series with an appropriate ballast resistor. These lamps often can operate across a wide range of voltages from 90V up to several hundred volts.
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The ferroresonant transformer, ferroresonant regulator or constant-voltage transformer is a type of saturating transformer used as a voltage regulator. These transformers use a tank circuit composed of a high-voltage resonant winding and a capacitor to produce a nearly constant average output voltage with a varying input current or varying load. The circuit has a primary on one side of a magnet shunt and the tuned circuit coil and secondary on the other side. The regulation is due to magnetic saturation in the section around the secondary.
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The International Electrotechnical Commission (IEC) defines supply system low voltage as voltage in the range 50 to 1000 V ac or 120 to 1500 V dc in IEC Standard VoltagesStandard Voltages, IEC 60038 which defines power distribution system voltages around the world. In electrical power systems low voltage most commonly refers to the mains voltages as used by domestic and light industrial and commercial consumers. "Low voltage" in this context still presents a risk of electric shock, but only a minor risk of electric arcs through the air.
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In electrical power , the US National Electrical Code (NEC), NFPA 70, article 725 (2005), defines low distribution system voltage (LDSV) as 0 to 49 V.. The NFPA standard 79 defines distribution protected extra-low voltage (PELV) as nominal voltage of 30 Vrms or 60 V dc ripple-free for dry locations, and 6 Vrms or 15 V dc in all other cases. UL standard 508A, article 43 (table 43.1) defines 0 to 20 V peak / 5 A or 20.1 to 42.4 V peak / 100 VA as low-voltage limited energy (LVLE) circuits.
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For example, electronic loads such as computer power supplies draw their current at the voltage peak to fill their internal storage elements. This can lead to a significant voltage drop near the supply voltage peak which shows as a flattening of the voltage waveform. This flattening causes odd harmonics which are not permissible if they exceed specific limits, as they are not only wasteful, but may interfere with the operation of other equipment. Harmonic emissions are mandated by law in EU and other countries to fall within specified limits.
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The manual type is applicable only for relatively low voltage and is known as a variable AC transformer (often referred to by the trademark name Variac). These are often used in repair shops for testing devices under different voltages or to simulate abnormal line voltages. The type with automatic voltage adjustment can be used as automatic voltage regulator, to maintain a steady voltage at the customers' service during a wide range of line and load conditions. Another application is a lighting dimmer that doesn't produce the EMI typical of most thyristor dimmers.
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That is, the op amp is being used as a voltage comparator. Note that a device designed primarily as a comparator may be better if, for instance, speed is important or a wide range of input voltages may be found, since such devices can quickly recover from full on or full off ("saturated") states. A voltage level detector can be obtained if a reference voltage Vref is applied to one of the op amp's inputs. This means that the op amp is set up as a comparator to detect a positive voltage.
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Electrical equipment may be designed with a floating ground for one of several reasons. One is safety. For example, a low voltage DC power supply, such as a mobile phone charger is connected to the mains through a transformer of one type or another, and there is no direct electrical connection between the current return path on the low-voltage side and physical ground (earth). Ensuring that there is no electrical connection between mains voltage and the low-voltage plug makes it much easier to guarantee safety of the supply.
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Loudspeaker transformer in old radio In the same way that transformers create high voltage power transmission circuits that minimize transmission losses, loudspeaker transformers can power many individual loudspeakers from a single audio circuit operated at higher than normal loudspeaker voltages. This application is common in public address applications. Such circuits are commonly referred to as constant-voltage speaker systems. Such systems are also known by the nominal voltage of the loudspeaker line, such as 25-, 70- and 100-volt speaker systems (the voltage corresponding to the power rating of a speaker or amplifier).
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Dual Miller theorem is usually implemented by an arrangement consisting of two voltage sources supplying the grounded impedance Z through floating impedances (see Fig. 3). The combinations of the voltage sources and belonging impedances form the two current sources – the main and the auxiliary one. As in the case of the main Miller theorem, the second voltage is usually produced by a voltage amplifier. Depending on the kind of the amplifier (inverting, non- inverting or differential) and the gain, the circuit input impedance may be virtually increased, infinite, decreased, zero or negative.
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The positive feedback of the rising phase slows and comes to a halt as the sodium ion channels become maximally open. At the peak of the action potential, the sodium permeability is maximized and the membrane voltage Vm is nearly equal to the sodium equilibrium voltage ENa. However, the same raised voltage that opened the sodium channels initially also slowly shuts them off, by closing their pores; the sodium channels become inactivated. This lowers the membrane's permeability to sodium relative to potassium, driving the membrane voltage back towards the resting value.
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Electrical breakdown in an electric discharge showing the ribbon-like plasma filaments from a Tesla coil. Electrical breakdown or dielectric breakdown is a process that occurs when an electrical insulating material, subjected to a high enough voltage, suddenly becomes an electrical conductor and electric current flows through it. All insulating materials undergo breakdown when the electric field caused by an applied voltage exceeds the material's dielectric strength. The voltage at which a given insulating object becomes conductive is called its breakdown voltage and depends on its size and shape.
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This is commonly used in switched-capacitor operational amplifiers to effectively double the gain of the charge sharing opamp, while adding an extra phase. When used in imagers, correlated double sampling is a noise reduction technique in which the reference voltage of the pixel (i.e., the pixel’s voltage after it is reset) is subtracted from the signal voltage of the pixel (i.e., the pixel’s voltage at the end of integration) at the end of each integration period, to cancel kTC noise (the thermal noise associated with the sensor's capacitance).
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Valves (also known as vacuum tubes) are very high input impedance (near infinite in most circuits) and high-output impedance devices. They are also high-voltage / low-current devices. The characteristics of valves as gain devices have direct implications for their use as audio amplifiers, notably that power amplifiers need output transformers (OPTs) to translate a high-output-impedance high-voltage low- current signal into a lower-voltage high-current signal needed to drive modern low-impedance loudspeakers (cf. transistors and FETs which are relatively low voltage devices but able to carry large currents directly).
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If you apply a voltage across a capacitor, it 'charges up' by storing the electrical charge as an electrical field inside the device. This means that while the voltage across the capacitor remains initially small, a large current flows. Later, the current flow is smaller because the capacity is filled, and the voltage raises across the device. A similar though opposite situation occurs in an inductor; the applied voltage remains high with low current as a magnetic field is generated, and later becomes small with high current when the magnetic field is at maximum.
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In the class-A triode amplifier, an anode resistor would be connected between the anode and the positive voltage source. For example, with Ra = 10000 ohms, the voltage drop on it would be VRa = Ia × Ra = 22.5V if an anode current of Ia = 2.25mA is chosen. If the input voltage amplitude (at the grid) changes from −1.5V to −0.5V (difference of 1V), the anode current will change from 1.2 to 3.3mA (see image). This will change the resistor voltage drop from 12 to 33V (a difference of 21V).
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Circuit diagram for threshold detector with hysteresis The threshold detector with hysteresis consists of an operational amplifier and a series of resistors that provide hysteresis. Like other detectors, this device functions as a voltage switch, but with an important difference. The state of the detector output is not directly affected by input voltage, but instead by the voltage drop across its input terminals (here, referred to as Va). From Kirchhoff's Current Law, this value depends both on Vin and the output voltage of the threshold detector itself, both multiplied by a resistor ratio.
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XLPE-insulated cables have a rated maximum conductor temperature of 90 °C and an emergency rating up to 140 °C, depending on the standard used. They have a conductor short-circuit rating of 250 °C. XLPE has excellent dielectric properties, making it useful for medium voltage—1 to 69 kV AC, and high- voltage cables—up to 380 kV AC-voltage, and several hundred kV DC. Numerous modifications in the basic polymer structure can be made to maximize productivity during the manufacturing process. For medium voltage applications, reactivity can be boosted significantly.
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The circuit to determine G∞ is shown in the bottom panel of Figure 7. The introduction of the ideal op amp (a nullor) in this circuit is explained as follows. When T → ∞, the gain of the amplifier goes to infinity as well, and in such a case the differential voltage driving the amplifier (the voltage across the input transistor rπ1) is driven to zero and (according to Ohm's law when there is no voltage) it draws no input current. On the other hand, the output current and output voltage are whatever the circuit demands.
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The lines have the same impedance to ground, so the interfering fields or currents induce the same voltage in both wires. Since the receiver responds only to the difference between the wires, it is not influenced by the induced noise voltage. If a balanced line is used in an unbalanced circuit, with different impedances from each conductor to ground, currents induced in the separate conductors will cause different voltage drops to ground, thus creating a voltage differential, making the line more susceptible to noise. Examples of twisted pairs include category 5 cable.
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This noise is rectified, producing a DC voltage when noise is present. The presence of continuous noise on an idle channel creates a DC voltage which turns the receiver audio off. When a signal with little or no noise is received, the noise-derived voltage is reduced and the receiver audio is unmuted. Some applications have the receiver tied to other equipment that uses the audio muting control voltage, as a "signal present" indication; for example, in a repeater the act of the receiver unmuting will switch on the transmitter.
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In this mode the diode and its associated filtering capacitor produce a voltage that is proportional to the peak of the sampled voltage. The operator of such a detector would not have a ready indication as to the mode in which the detector diode is operating and therefore differentiating the results between SWR or so called PSWR is not practical. Perhaps even worse, is the common case where the minimum detected voltage is below the knee and the maximum voltage is above the knee. In this case, the computed results are largely meaningless.
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The phase angles in the equations for the impedance of capacitors and inductors indicate that the voltage across a capacitor lags the current through it by a phase of \pi/2, while the voltage across an inductor leads the current through it by \pi/2. The identical voltage and current amplitudes indicate that the magnitude of the impedance is equal to one. The impedance of an ideal resistor is purely real and is called resistive impedance: :\ Z_R = R In this case, the voltage and current waveforms are proportional and in phase.
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Voltage Inc (ボルテージ) is a Japanese developer and publisher of interactive story apps, such as visual novels and otome games, for iOS and Android devices. They also develop games with their San Francisco based subsidiary Voltage Entertainment USA.
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Small or low voltage electrolytic capacitors may be safely connected in parallel. Large sizes capacitors, especially large sizes and high voltage types should be individually protected against sudden discharge of the whole bank due to a failed capacitor.
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Voltage-gated potassium channels (VGKCs) are transmembrane channels specific for potassium and sensitive to voltage changes in the cell's membrane potential. During action potentials, they play a crucial role in returning the depolarized cell to a resting state.
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Voltage-dependent calcium channels can be distinguished based on their voltage-dependence, deactivation, and single-channel conductance. Low-voltage-activated calcium channels are referred to as 'T' type because their currents are both transient, owing to fast inactivation, and tiny, owing to small conductance. T-type channels are thought to be involved in pacemaker activity, low-threshold calcium spikes, neuronal oscillations and resonance, and rebound burst firing.
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Some CT configurations slip around the bushing of a high-voltage transformer or circuit breaker, which automatically centers the conductor inside the CT window. Current transformers can be mounted on the low voltage or high voltage leads of a power transformer. Sometimes a section of a bus bar can be removed to replace a current transformer. Often, multiple CTs are installed as a "stack" for various uses.
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The electro (co)polymerization means inserting three electrodes (reference electrode, counter electrode and working electrode) into solution including reactors or monomers. By applying voltage to electrodes, redox reaction to synthesize polymer is promoted. Electro (co)polymerization can also be divided into Cyclic Voltammetry and Potentiostatic method by applying cyclic voltage and constant voltage. The advantage of Electro (co)polymerization are the high purity of products.
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Usually there are two igniter plugs in different positions in the combustion system. A high voltage spark is used to ignite the gases. The voltage is stored up from a low voltage (usually 28 V DC) supply provided by the aircraft batteries. It builds up to the right value in the ignition exciters (similar to automotive ignition coils) and is then released as a high energy spark.
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The area required for a converter station is much larger than a conventional transformer, for example a site with a transmission rating of 600 megawatts and a transmission voltage of 400 kV is approximately 300 x 300 metres (1000 x 1000 feet). Lower-voltage plants may require somewhat less ground area, since less air space clearance would be required around outdoor high-voltage equipment.
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They provide load current during both halves of the AC supply voltage. By combining the functions of diacs and triacs, quadracs eliminate the need to buy and assemble discrete parts. Quadracs are used in lighting control, speed control, and temperature modulation control applications. They carry performance specifications such as peak repetitive off voltage, peak repetitive reverse voltage, root mean square (RMS) on-state current, and temperature junction.
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Kurtoxin inhibits ion calcium channels by modifying channel gating. The effect of the toxin is voltage-dependent. In a voltage-clamp experiment it was found that calcium channels are more strongly inhibited by minor depolarization than by a strong depolarization of the cell. The peptide toxin binds close to the channel voltage sensor and thereby produces complex gating modifications specific for each channel type.
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Susceptibility of electronic equipment to these other electric power disturbances is defined by other aspects of the system design, either inside the equipment itself or externally by means such as a UPS, a voltage regulator or a surge protector with built-in overvoltage protection (which typically consists of a voltage-sensing circuit and a relay for disconnecting the AC input when the voltage reaches a danger threshold).
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Commissioning of the completed power station is expected in December 2019. In September 2019, an estimated 95 percent of construction had been completed. This included 100 percent completion of the Karuma–Lira High Voltage Line, 100 percent of the Karuma–Kawanda High Voltage Power Line and 98 percent of the Karuma–Olwiyo High Voltage Line. Commissioning of the power station is planned for December 2019.
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However, because very short pulses often call for very high voltage and low capacitance, to keep the current density from rising too high, some microsecond flashtubes are triggered by simply "over-volting", that is, by applying a voltage to the electrodes which is much higher than the lamp's self-flash threshold, using a spark gap. Often, a combination of simmer voltage and over-volting is used.
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Alternatively, more modern systems are available with low voltage (10, 12, or 24 volts) running through the track, which is in itself decorative. In this case, the fixture may clamp onto a track made of two metal strips separated with an insulating strip. Two-circuit configurations are rare in such systems. The track is powered by a transformer which converts the high voltage into low voltage.
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First, the molding coat is cut to reveal the circuitry. Then, the engineer repeatedly scans the surface while grinding the layers of the chip. There are several operations to scan the circuitry. Typical visual inspection methods are: scanning optical microscopy (SOM), scanning electron microscopy (SEM), pico-second imaging circuit analysis (PICA), voltage contrast imaging (VCI), light induced voltage alteration (LIVA) or charge induced voltage alteration (CIVA).
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See Figures 4 & 5 for Pulse Life Curves.. Every time an MOV activates (shorts,) its threshold voltage reduces slightly. After many spikes the threshold voltage can reduce enough to be near the protection voltage, either mains or data. At this point the MOV conducts more and more often, heats up and finally fails. In data circuits, the data channel becomes shorted and non-functional.
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In addition to heterodyne detection, STJs can also be used as direct detectors. In this application, the STJ is biased with a dc voltage less than the gap voltage. A photon absorbed in the superconductor breaks Cooper pairs and creates quasiparticles. The quasiparticles tunnel across the junction in the direction of the applied voltage, and the resulting tunneling current is proportional to the photon energy.
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Available on-line at: . An induction coil produces an intermittent high-voltage alternating current from a low- voltage direct current supply. It has a primary coil consisting of a few turns of thick wire wound around an iron core and subjected to a low voltage (usually from a battery). Wound on top of this is a secondary coil made up of many turns of thin wire.
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The Chroma's sixteen synthesizer channels consist of one Voltage Controlled Oscillator, Waveshaper, Filter, and Amplifier under software control via multiplexed analog voltage control channels. The channels are grouped into eight pairs. One channel in each pair is labelled "A" and the other "B". Although the oscillators, filters and amplifiers themselves are voltage controlled, the overall control of the synthesizer channels is entirely in software.
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This voltage is called VCC pumped (VCCP). The time required to discharge a capacitor thus depends on what logic value is stored in the capacitor. A capacitor containing logic one begins to discharge when the voltage at the access transistor's gate terminal is above VCCP. If the capacitor contains a logic zero, it begins to discharge when the gate terminal voltage is above VTH.
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Two-electrode voltage clamp The two- electrode voltage clamp (TEVC) technique is used to study properties of membrane proteins, especially ion channels. Researchers use this method most commonly to investigate membrane structures expressed in Xenopus oocytes. The large size of these oocytes allows for easy handling and manipulability. The TEVC method utilizes two low-resistance pipettes, one sensing voltage and the other injecting current.
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Other devices may be powered from the telecommunications DC system using a DC-DC converter to provide any convenient voltage. Many telephones connect to a twisted pair of wires, and use a bias tee to internally separate the AC component of the voltage between the two wires (the audio signal) from the DC component of the voltage between the two wires (used to power the phone).
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A device to check battery voltage A battery's capacity is the amount of electric charge it can deliver at the rated voltage. The more electrode material contained in the cell the greater its capacity. A small cell has less capacity than a larger cell with the same chemistry, although they develop the same open-circuit voltage. Capacity is measured in units such as amp-hour (A·h).
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Nature 387:869-875 The difference in excitability can be attributed to the presence of these voltage-gated potassium channels. Voltage-gated potassium channels inhibit the ability of dendrites to generate action potentials and decrease the amplitude of dendritic spikes with increasing distance from the soma. The ability of voltage-gated potassium channels to modulate dendritic signaling may have significant effects on synaptic plasticity.
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Structure and use of NPN transistor. Arrow according to schematic. The diagram shows a schematic representation of an NPN transistor connected to two voltage sources. (The same description applies to a PNP transistor with reversed directions of current flow and applied voltage.) This applied voltage causes the lower P-N junction to become forward biased, allowing a flow of electrons from the emitter into the base.
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Voltage dependent sodium channels detect a change in membrane potential with the voltage sensor S3-S4. When the change in voltage reaches the threshold for an action potential, the ion channel opens and sodium ions diffuse into the cell. The general target for scorpion β-toxins is the receptor site 4 of Navs. Scorpion depressant β-scorpion toxins have a high affinity for Navs of insects.
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Then the field of piezotronics was coined, representing the electronics in which the piezopotential acts as a gate voltage. Based on the piezotronics, the design of traditional CMOS transistor can be essentially changed. First, the piezotronic transistor can have no gate electrode. Second, an internal piezopotential displaces the gate voltage applied, and the applied strain is used to control the device instead of the gate voltage.
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For 240 V operation, the switch configures the system as a full- wave bridge, re-connecting the capacitor center-tap wire to the open AC terminal of a bridge rectifier system. This allows 120 or 240 V operation with the addition of a simple SPDT switch. A voltage tripler is a three-stage voltage multiplier. A tripler is a popular type of voltage multiplier.
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The Acceleration factor (AF) is a multiplier that relates a product's life at an accelerated stress level to the life at the use stress level. An AF of 20 means 1 hour at stress condition is equivalent to 20 hours at useful condition. The voltage acceleration factor is represented by AFv. Usually the stress voltage is equal to or higher than the maximum voltage.
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High Voltage Software chose the characters they liked best from these themes and created character studies for them to "capture the mood of each persona". Certain characters would assume the role of bosses, while others were featured as less skilled opponents. The developers also created two original characters, Rocket Racer and Veronica Voltage. High Voltage Software spent over a year creating Lego Racers' car building mechanics.
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Neon lamps are commonly used as low-voltage surge protectors, but they are generally inferior to gas discharge tube (GDT) surge protectors (which can be designed for higher voltage applications). Neon lamps have been used as an inexpensive method to protect RF receivers from voltage spikes (lamp connected to RF input and chassis ground), but they are not suitable for higher-power RF transmitters.
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Because the size of the molecule affects its mobility, smaller fragments end up nearer to the anode than longer ones in a given period. After some time, the voltage is removed and the fragmentation gradient is analyzed. For larger separations between similar sized fragments, either the voltage or run time can be increased. Extended runs across a low voltage gel yield the most accurate resolution.
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Electric power from a generating station is transmitted to grid substations using a three-phase distribution system. At the grid substation, a step-down transformer is connected across two of the three phases of the high-voltage supply. The transformer lowers the voltage to which is supplied to a railway feeder station located beside the tracks. SVCs are used for load balancing and voltage control.
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They may have four terminals, using one pair to carry an operating current and the other pair to measure the voltage drop; this eliminates errors caused by voltage drops across the lead resistances, because no charge flows through voltage sensing leads. It is important in small value resistors (100–0.0001 ohm) where lead resistance is significant or even comparable with respect to resistance standard value.
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The collector voltage drops because of reduced resistance from the collector to emitter. If the voltage difference between the collector and emitter were zero (or near zero), the collector current would be limited only by the load resistance (light bulb) and the supply voltage. This is called saturation because the current is flowing from collector to emitter freely. When saturated, the switch is said to be on.
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A clamping circuit (also known as a clamper) will bind the upper or lower extreme of a waveform to a fixed DC voltage level. These circuits are also known as DC voltage restorers. Clampers can be constructed in both positive and negative polarities. When unbiased, clamping circuits will fix the voltage lower limit (or upper limit, in the case of negative clampers) to 0 volts.
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A positive unbiased clamp. In the negative cycle of the input AC signal, the diode is forward biased and conducts, charging the capacitor to the peak negative value of VIN. During the positive cycle, the diode is reverse biased and thus does not conduct. The output voltage is therefore equal to the voltage stored in the capacitor plus the input voltage, so VOUT = VIN \+ VINpeak.
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These channels are activated when an action potential arrives from a neighbouring cell, through gap junctions. When this happens, the voltage within the cell increases slightly. If this increased voltage reaches a certain value (threshold potential; ~-70 mV) it causes the Na+ channels to open. This produces a larger influx of sodium into the cell, rapidly increasing the voltage further (to ~ +50 mV; i.e.
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As shown in the diagram, the perpendicular component of the stator field affects the torque while the parallel component affects the voltage. The load supplied by the generator determines the voltage. If the load is inductive, then the angle between the rotor and stator fields will be greater than 90 degrees which corresponds to an increased generator voltage. This is known as an overexcited generator.
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Dynamic frequency scaling is another power conservation technique that works on the same principles as dynamic voltage scaling. Both dynamic voltage scaling and dynamic frequency scaling can be used to prevent computer system overheating, which can result in program or operating system crashes, and possibly hardware damage. Reducing the voltage supplied to the CPU below the manufacturer's recommended minimum setting can result in system instability.
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Battery simulator mimics a battery’s electrical characteristic of outputting a voltage and able to source as well as sink current. A battery simulator is a special kind of power supply that can output positive voltage while can sink and source current. This type of power supply is called two-quadrant power supply. In contrast, a conventional power supply can only source current when the voltage is positive.
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For example, a battery simulator can easily adjust its voltage over the range of 0V to 4.2V to test a lithium-ion battery charger. Battery simulator is powerful and convenient tool for testing battery chargers. Lithium ion charger voltage/current profile obtained using a battery simulator. Once the simulated battery voltage is set, the user connects the charger to be tested to the input of the simulator.
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The hammer hits the piezo-electric crystal. Due to piezo-electric effect, a high voltage is generated in the range of 800 volts. The lighter is wired in such a way that this whole voltage is applied in a small region of air gap between two metallic points. Due to high voltage generated, the air is ionized and acts as a path for the discharge.
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The voltage starts to increase again as the armature heads to the opposite pole at the 270° position. Toward this position, the current is generated on the opposite direction, giving out the maximum voltage on the opposite side. The voltage decrease again as it completes the full rotation. In one rotation, the AC output is produced with one complete cycle as represented in the sine wave.
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Phases with higher relative loading will experience reduced voltage, and phases with lower relative loading will experience elevated voltage, up to the phase-to-phase voltage. A high-leg delta provides phase-to-neutral relationship of , however, LN load is imposed on one phase. A transformer manufacturer's page suggests that LN loading not exceed 5% of transformer capacity. Since ≈ 1.73, defining as 100% gives .
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The circuit consists of a resistive divider network, a set of op-amp comparators and a priority encoder. A small amount of hysteresis is built into the comparator to resolve any problems at voltage boundaries. At each node of the resistive divider, a comparison voltage is available. The purpose of the circuit is to compare the analog input voltage with each of the node voltages.
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This forms a negative feedback control loop; increasing the open-loop gain tends to increase regulation accuracy but reduce stability. (Stability is avoidance of oscillation, or ringing, during step changes.) There will also be a trade-off between stability and the speed of the response to changes. If the output voltage is too low (perhaps due to input voltage reducing or load current increasing), the regulation element is commanded, up to a point, to produce a higher output voltage–by dropping less of the input voltage (for linear series regulators and buck switching regulators), or to draw input current for longer periods (boost-type switching regulators); if the output voltage is too high, the regulation element will normally be commanded to produce a lower voltage. However, many regulators have over-current protection, so that they will entirely stop sourcing current (or limit the current in some way) if the output current is too high, and some regulators may also shut down if the input voltage is outside a given range (see also: crowbar circuits).
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Power MOSFETs have a maximum specified drain to source voltage (when turned off), beyond which breakdown may occur. Exceeding the breakdown voltage causes the device to conduct, potentially damaging it and other circuit elements due to excessive power dissipation.
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Like a typical diode, there is a fixed anode and cathode in a Zener diode, but it will conduct current in the reverse direction (electrons flow from anode to cathode) if its breakdown voltage or "Zener voltage" is exceeded.
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DC injection brake module DC injection braking is a method of slowing AC electric motors. A DC voltage is injected into the winding of the AC motor after the AC voltage is disconnected, providing braking force to the rotor.
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After further voltage conversions in the transmission network, the voltage is finally transformed to the standard utilization before power is supplied to customers. Most automotive alternators generate three-phase AC and rectify it to DC with a diode bridge.
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Welding machines are usually classified as constant current (CC) or constant voltage (CV); a constant current machine varies its output voltage to maintain a steady current while a constant voltage machine will fluctuate its output current to maintain a set voltage. Shielded metal arc welding and gas tungsten arc welding will use a constant current source and gas metal arc welding and flux-cored arc welding typically use constant voltage sources but constant current is also possible with a voltage sensing wire feeder. If a welder were to attempt to use a CV machine for a shielded metal arc welding (SMAW) task, the small fluctuations in the arc distance would cause significant fluctuations in the machine's current output. With a CC machine the welder can count on a fixed number of amps reaching the material, regardless of how short or long the electric arc gets.
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They showed that the displacement and velocity depended directly on the applied voltage.
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The label also includes Ancient Shapes, Public Animal,'63 Monroe, and C.C. Voltage.
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The Cav2.1 P/Q voltage-dependent calcium channel is encoded by the gene.
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In operation the components can have a voltage of several hundred thousand volts.
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Similar reactors are used for current limiting at transmission and distribution voltage levels.
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A 1 MW installation can impact on local voltage, and disturb system frequency.
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A surge protector absorbs voltage spikes to protect the next stage from damage.
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A SEPIC converter is able to step-up or step-down the voltage.
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This is because a voltage generator applying zero volts is a short circuit.
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High Voltage Magazine is a magazine that was first published in November 2003.
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It is now the Ridgefield Rail Trail and high voltage power line corridor.
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These modifications are known as "voltage mods" or "Vmod" in the overclocking community.
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High Voltage is the debut studio album by Australian hard rock band AC/DC, released only in Australia, on 17 February 1975. Their first international release in 1976 would also be named High Voltage, though with a radically different track list.
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This entire verification example could also have been done with a voltage source in place of the current source and an inductor in place of the capacitor. We would have then been solving for a current instead of a voltage.
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The common mode output voltage is 2.5–4 V. The receiver's input impedance should be 100 ohms, within 10%. the receiver input's common mode voltage must be between -1 and 7 V. The receiver's sensitivity should be at least 200 mV.
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The highly conserved S4 segment acts as the channel's voltage sensor. The voltage sensitivity of this channel is due to positive amino acids located at every third position.Nicholls, Martin, Fuchs, Brown, Diamond, Weisblat. (2012) "From Neuron to Brain," 5th ed. pg.
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According to Chris Horwill, there are also four main design ratings in the SVC mode. The first one is the Dynamic range. This one is at 225 MVAr, or −115 MVAr at nominal voltage. The next one is the Target voltage.
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The operational amplifier integrator is an electronic integration circuit. Based on the operational amplifier (op-amp), it performs the mathematical operation of integration with respect to time; that is, its output voltage is proportional to the input voltage integrated over time.
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2nd Nat. Dairy Housing Conf., 1983 of stray voltage in the farm environment. Today, stray voltage on farms is regulated by state governments and controlled by the design of equipotential planes in areas where livestock eat, drink or give milk.
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This voltage has two functions: first, it provides a power source for an assortment of voltage-dependent protein machinery that is embedded in the membrane; second, it provides a basis for electrical signal transmission between different parts of the membrane.
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Originally, it had diode voltage selector. A later, modernised series, the 3xx subseries, include thyristor voltage selector, and an on-board computer. Later 3xx series have an onboard look-behind-camera for video surveillance of the sides and also new livery.
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Conceptual symmetries of resistor, capacitor, inductor, and memristor. Chua in his 1971 paper identified a theoretical symmetry between the non-linear resistor (voltage vs. current), non-linear capacitor (voltage vs. charge), and non-linear inductor (magnetic flux linkage vs. current).
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Cheetham work with the Maple State and they first featured with High Voltage on the second compilation album Full Charge. After that they released two single and one mini-album, the album being the latest record released by High Voltage.
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The metering signal is used by a closed-loop controller that regulates the high voltage by controlling inverter input power, and it may also be conveyed out of the power supply to allow external circuitry to monitor the high-voltage output.
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Power can be safely generated to about 2000 volts, but this is a dangerous voltage for household use. With alternating current voltage can be changed up or down using a transformer. AC power began being widely introduced in the 1890s.
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Filament voltage was obtained from Signal Corps alkaline storage batteries and the high voltage was provided by conventional "B" batteries. By today's standards such a receiver would be useless with crowded signals, but at that time it worked out fairly well.
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Automotive alternators require a voltage regulator which operates by modulating the small field current to produce a constant voltage at the battery terminals. Early designs (c.1960s–1970s) used a discrete device mounted elsewhere in the vehicle. Intermediate designs (c.
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The product range is comprehensive. Drives for low voltage as well as medium voltage applications are available with complete industry specific customised solution. It makes electrical motors (induction and synchronous) and generators. These are often found in fossil fuel power stations.
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In the lower voltage range, around 115 V, this switch is turned on changing the power grid voltage rectifier into a voltage doubler in delon circuit design. As a result, the large primary filter capacitor behind that rectifier was split up into two capacitors wired in series, balanced with bleeder resistors and varistors that were necessary in the upper input voltage range, around 230 V. Connecting the unit configured for the lower range to a higher-voltage grid usually resulted in an immediate permanent damage. When the power factor correction (PFC) was required, those filter capacitors were replaced with higher-capacity ones, together with a coil installed in series to delay the inrush current. This is the simple design of a passive PFC.
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The "voltage" coil above the disc is in parallel with the supply; its many turns have a high inductance/resistance ratio (Q) so its current and magnetic field are the time integral of the applied voltage, lagging it by 90 degrees. This magnetic field passes down perpendicularly through the disc, inducing circular eddy currents in the plane of the disc centered on the field. These induced currents are proportional to the time derivative of the magnetic field, leading it by 90 degrees. This puts the eddy currents in phase with the voltage applied to the voltage coil, just as the current induced in the secondary of a transformer with a resistive load is in phase with the voltage applied to its primary.
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Note that the definition allows for an arbitrary constant of integration—this is why absolute values of voltage are not meaningful. In general, electric fields can be treated as conservative only if magnetic fields do not significantly influence them, but this condition usually applies well to biological tissue. Because the electric field is the gradient of the voltage distribution, rapid changes in voltage within a small region imply a strong electric field; on the converse, if the voltage remains approximately the same over a large region, the electric fields in that region must be weak. A strong electric field, equivalent to a strong voltage gradient, implies that a strong force is exerted on any charged particles that lie within the region.
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In n-channel enhancement-mode devices, a conductive channel does not exist naturally within the transistor, and a positive gate- to-source voltage is necessary to create one such. The positive voltage attracts free-floating electrons within the body towards the gate, forming a conductive channel. But first, enough electrons must be attracted near the gate to counter the dopant ions added to the body of the FET; this forms a region with no mobile carriers called a depletion region, and the voltage at which this occurs is the threshold voltage of the FET. Further gate-to-source voltage increase will attract even more electrons towards the gate which are able to create a conductive channel from source to drain; this process is called inversion.
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Except for permanent magnet generators, a generator produces output voltage proportional to the magnetic field, which is proportional to the excitation current; if there is no excitation current there is no voltage. A small amount of power supplied as field current may thus control a large amount of generated power and can be used to modulate it. This principle is very useful for voltage control: if the output voltage of the system is less than desired, the excitation current can be increased; if the output voltage is high, excitation can be decreased. A synchronous condenser operates on the same principle, but there is no "prime mover" power input; however, rotational inertia means that it can send or receive power over short periods of time.
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If a voltage is applied to the BJT base-emitter junction as an input quantity and the collector current is taken as an output quantity, the transistor will act as an exponential voltage-to-current converter. By applying a negative feedback (simply joining the base and collector) the transistor can be "reversed" and it will begin acting as the opposite logarithmic current-to-voltage converter; now it will adjust the "output" base-emitter voltage so as to pass the applied "input" collector current. The simplest bipolar current mirror (shown in Figure 1) implements this idea. It consists of two cascaded transistor stages acting accordingly as a reversed and direct voltage-to-current converters. The emitter of transistor Q1 is connected to ground.
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While the multiplier can be used to produce thousands of volts of output, the individual components do not need to be rated to withstand the entire voltage range. Each component only needs to be concerned with the relative voltage differences directly across its own terminals and of the components immediately adjacent to it. Typically a voltage multiplier will be physically arranged like a ladder, so that the progressively increasing voltage potential is not given the opportunity to arc across to the much lower potential sections of the circuit. Note that some safety margin is needed across the relative range of voltage differences in the multiplier, so that the ladder can survive the shorted failure of at least one diode or capacitor component.
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Because the FG is electrically isolated by its insulating layer, electrons placed on it are trapped. When the FG is charged with electrons, this charge screens the electric field from the CG, thus, increasing the threshold voltage (VT1) of the cell. This means that now a higher voltage (VT2) must be applied to the CG to make the channel conductive. In order to read a value from the transistor, an intermediate voltage between the threshold voltages (VT1 & VT2) is applied to the CG. If the channel conducts at this intermediate voltage, the FG must be uncharged (if it was charged, we would not get conduction because the intermediate voltage is less than VT2), and hence, a logical "1" is stored in the gate.
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In spite of the above definitions, the term stray voltage continues to be used by both utility workers and the general public for all occurrences of unwanted excess electricity. For example, at the annual "Jodie S. Lane Stray Voltage Detection, Mitigation & Prevention Conference", held at the Con Edison headquarters in New York City in April 2009, which attracted the presidents of most major utilities from throughout the United States and Canada, the utility leaders continued to use stray voltage for all occurrences of unwanted excess electricity. The term contact voltage was used only once, possibly because "contact voltage" is generally the fault of the supply, network or installation company. Few companies are willing to openly discuss faults of theirs, let alone ones as life-threatening.
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Although classed as a "bipolar" HVDC scheme, the NorNed scheme is unusual for a Line-Commutated (thyristor-based) HVDC scheme since there is just one 12-pulse converter at each end of the scheme, midpoint-grounded at Eemshaven. With voltage-source converter-based HVDC systems, this arrangement with the two high voltage cables at equal and opposite voltages but only a single converter at each end is referred to as a Symmetrical monopole. Consequently, with a DC voltage of ±450 kV, the converter for the NorNed project has a terminal to terminal DC voltage rating of 900 kV, making it (as of 2012) the highest voltage rating of any HVDC converter in the world. The connection has a loss of 4.2% (95.8% efficiency).
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That is, if the measurement of ground resulted in an output of 0.001 volts, one can assume that all measurements will be offset by the same amount and can subtract 0.001 from all subsequent results. Gain error can similarly be measured and corrected internally (again assuming that there is a constant gain error over the entire output range). The voltage reference (or some voltage derived directly from the reference) can be used as the input to the converter. If the assumption is made that the voltage reference is accurate (to within the tolerances of the converter) or that the voltage reference has been externally calibrated against a voltage standard, any error in the measurement would be a gain error in the converter.
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We describe this by a physical time-dependent current . With this comes a change in voltage, or the electrical potential energy difference between the cell and its surroundings, which is observed to sometimes result in a voltage spike called an action potential which travels the length of the cell and triggers the release of further neurotransmitters. The voltage, then, is the quantity of interest and is given by .
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The signal may be amplified before detection. If not, a very low voltage drop diode or a diode biased with a fixed voltage must be used. When using a rectifier for demodulation the capacitor and load resistance must be carefully matched: too low a capacitance makes the high frequency carrier pass to the output, and too high makes the capacitor just charge and stay charged. Rectifiers supply polarised voltage for welding.
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In analog systems, each horizontal line is transmitted as a high-frequency analog signal. Each picture element (pixel) is therefore converted to an analog electrical value (voltage), and changes in values between pixels therefore become changes in voltage. The transmission standards require that the sampling be done in a fixed time (outlined below), so more pixels per line becomes a requirement for more voltage changes per unit time, i.e. higher frequency.
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Basic linear regulator configurations. The fourth circuit requires an additional positive power supply voltage, ΔU, for low-dropout operation. Series resistor RA decouples the TL431 from gate capacitance The simplest TL431 regulator circuit is made by shorting control input to cathode. The resulting two-terminal network has a zener-like current–voltage characteristic, with a stable threshold voltage VREF≈2,5 V, and low-frequency impedance of around 0.2 Ohm.
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Optimal transient speed is attained at 10% (≈250 mV) overdrive and source impedance of 10 kOhm or less. On-state VCA drops to around 2 V, which is compatible with TTL and CMOS logic gates with 5 V power supply. Low-voltage CMOS (e.g. 3.3 V or 1.8 V logic) requires level conversion with a resistive voltage divider, or replacing TL431 with a low- voltage alternative like the TLV431.
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Metal-oxide varistor manufactured by Siemens & Halske AG. Modern varistor schematic symbol. A varistor is an electronic component with an electrical resistance that varies with the applied voltage. Also known as a voltage- dependent resistor (VDR), it has a nonlinear, non-ohmic current–voltage characteristic that is similar to that of a diode. In contrast to a diode however, it has the same characteristic for both directions of traversing current.
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MOVs are specified according to the voltage range that they can tolerate without damage. Other important parameters are the varistor's energy rating in joules, operating voltage, response time, maximum current, and breakdown (clamping) voltage. Energy rating is often defined using standardized transients such as 8/20 microseconds or 10/1000 microseconds, where 8 microseconds is the transient's front time and 20 microseconds is the time to half value.
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TransGrid operates the major high voltage electricity transmission network in NSW and the ACT, and is part of the National Electricity Market (NEM). The network connects generators, distributors and major end users. TransGrid's network comprises 104 bulk supply substations and more than 13,133 kilometres of high voltage transmission lines and cables. The network operates primarily at voltage levels of 500 kV, 330 kV, 220 kV and 132 kV.
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Sea Bed Turbine A tidal farm is a group of multiple tidal stream generators assembled in the same location used for production of electric power,Definition of tidal farm similar to that of a wind farm. The low-voltage powerlines from the individual units are then connected to a substation, where the voltage is stepped up with the use of a transformer for distribution through a high voltage transmission system.
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Assuming that a receiver is nearly tuned to the desired frequency, the AFC circuit in the receiver develops an error voltage proportional to the degree to which the receiver is mistuned. This error voltage is then fed back to the tuning circuit in such a way that the tuning error is reduced. In most frequency modulation (FM) detectors, an error voltage of this type is easily available. See Negative feedback.
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The lines in the picture are located in eastern Utah. High voltages have disadvantages, such as the increased insulation required, and generally increased difficulty in their safe handling. In a power plant, energy is generated at a convenient voltage for the design of a generator, and then stepped up to a high voltage for transmission. Near the loads, the transmission voltage is stepped down to the voltages used by equipment.
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The ribbon is a linear potentiometer that generates different control voltages depending on where it is touched. Thus, the modern ribbon on the Persephone replaces the nickel-chrome resistance wire used as a variable resistor to control the pitch of the trautonium1. These changes in voltage are applied to the voltage-controlled oscillator and the filter. The voltage fluctuations are also translated into binary data and used to control digital modulation.
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Phrixotoxin-1 and -2 bind to A-type, transient, voltage-gated potassium channels, near the S3 and S4 segments, where they negatively affect transmembrane movement of the voltage sensing domain in response to depolarizing voltages. They bind preferentially to the closed or inactivated state of Kv4.2 and Kv4.3 channels. Phrixotoxin-3 (PaurTx3) inhibits several voltage gated sodium channel subtypes (Nav1.1/SCN1A, Nav1.2/SCN2A, Nav1.4/SCN4A, Nav1.5/SCN5A, and Nav1.8/SCN10A) .
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When positive charge builds up on one side of a membrane containing such voltage sensors, it generates an electric force pressing the S4 in the opposite direction. Changes in membrane potential therefore move the S4 back and forth through the membrane, allowing the voltage sensor to act like a switch. Activation of the voltage sensor occurs at depolarized potentials, i.e.: when the membrane collects more positive charge on the inner leaflet.
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Power and voltage are specified in the same way as single-phase systems. However, due to differences in what these terms usually represent in three-phase systems, the relationships for the derived units are different. Specifically, power is given as total (not per-phase) power, and voltage is line-to-line voltage. In three-phase systems the equations P = S\cos(\phi) and Q = S\sin(\phi) also hold.
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Often utilities use load management systems to turn off customers' air conditioners, water heaters, and pool pumps to reduce demand. Voltage reduction has become another option for utilities to reduce demand--typically unbeknownst to the customer. However, only the resistive portion of the load responds to the reduction in voltage to reduce aggregate demand. Loads such as incandescent lights and heater coils will use less power as the voltage is lowered.
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Practical electronic converters use switching techniques. Switched-mode DC-to-DC converters convert one DC voltage level to another, which may be higher or lower, by storing the input energy temporarily and then releasing that energy to the output at a different voltage. The storage may be in either magnetic field storage components (inductors, transformers) or electric field storage components (capacitors). This conversion method can increase or decrease voltage.
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