2 Sentences With "vacuum tube hearing aid"

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One of the first manufacturers of the electronically amplified hearing aid was the Siemens company in 1913. Their hearing aids were bulky and not easily portable. They were about the size of a "tall cigar box" and had a speaker that would fit in the ear. The first vacuum-tube hearing aid was patented by a Naval engineer Earl Hanson in 1920.

During the 1920s and 1930s, the vacuum tube hearing aid became more successful and began to decrease in size with better miniaturization techniques. The Acousticon's Model 56 was created in the mid-1920s and was one of the first portable hearing aid units, although it was quite heavy. The first wearable hearing aid using vacuum tube technology went on sale in England in 1936, and a year later in the United States. By the 1930s, hearing aids were becoming popular to the public.

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