33
/es/
AIzaSyAYiBZKx7MnpbEhh9jyipgxe19OcubqV5w
August 1, 2025
1022037
313841
2
Public Timelines
Public TimelinesFAQ
Public TimelinesFAQ
For educational institutions For teachers For students Cabinet
For educational institutions For teachers For students Open cabinet
Crear
Create a timeline
Public timelines
Library
FAQ

The Vacuum Tube Age of Hearing Aids (1 ene 1920 año – 1 ene 1949 año)

Descripción:

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.

Añadido al timeline:

A Brief History of the Hearing Aid

ByBrenda Perez
28 oct 2019
0
0
195

fecha:

1 ene 1920 año
1 ene 1949 año
~ 29 years

Fotos:

About & FeedbackAcuerdoPrivacidadBibliotecaFAQ
Support 24/7  
CabinetGet premium
Donate
The service accepts bank transfer (ACH, Wire) or cards (Visa, MasterCard, etc). Processed by Stripe.
Secured with SSL