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The Vacuum Tube Age of Hearing Aids (1 gen 1920 anni – 1 gen 1949 anni)

Descrizione:

Earl C. Hanson invented the vacuum tube hearing aid and named it the vactuphone. Was one of the first hearing aids that a person could wear around the ear. Technology for amplification was better than previous hearing aids, though this hearing aid required two batteries making the cost greater.

Aggiunto al nastro di tempo:

A Brief History of the Hearing Aid

ByBrenda Perez
28 ott 2019
0
0
195

Data:

1 gen 1920 anni
1 gen 1949 anni
~ 29 years

Immagini:

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