Hearing aid
device · 1898 · Electric age
An electronic sound amplifier for people with hearing loss.
What it is made of
- Microphone — has part. A microphone.
- Amplifier — has part. An amplifier.
- Loudspeaker — has part. A miniature loudspeaker.
Principles and materials it uses
- Carbon — is made of. The first hearing aids used a carbon microphone.
History: what it evolved from and what it influenced
- Telephone — evolved from. The first electric hearing aids were built from telephone components.