carbon transmitter

electronics

Also known as: carbon-button transmitter

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

June 22, 2026

Quick Summary

A carbon microphone is a type of microphone that operates by altering the electrical resistance of carbon contacts. This process converts acoustic power into electric power, with similar wave characteristics. Sound waves cause a diaphragm to move, which in turn changes the resistance of the carbon contact within the microphone's electrical circuit.12

While historically used in telephone transmitters, microphones are now widely applied in various devices such as hearing aids, sound recording systems, and public-address systems.2

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

2 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

telephone
Transmitter
In traditional carbon transmitters, developed in the 1880s, a thin layer of carbon granules separates a fixed electrode from a diaphragm-activated electrode. Electric current flows through the carbon against a certain resistance. The diaphragm, vibrating in response to the speaker’s voice, forces the movable electrode to exert…
Read More
In traditional carbon transmitters, developed in the 1880s, a thin layer of carbon granules separates a fixed electrode from a diaphragm-activated electrode. Electric current flows through the carbon against a certain resistance. The diaphragm, vibrating in response to the speaker’s voice, forces the movable electrode to exert…
Read More

Thomas Edison
Menlo Park
…1877 Edison had developed the carbon-button transmitter that was used in telephone speakers and microphones for a century thereafter.
Read More
…1877 Edison had developed the carbon-button transmitter that was used in telephone speakers and microphones for a century thereafter.
Read More