The Bell and Carbon Microphone

How the carbon button mic worked and the Bell magnetically driven mic before that. B. Lillquist shows us a later Shure Brothers carbon mic, also known as a "carbon transmitter". The carbon mic was used with early AM radio, music recording and was the main form of mic used in telephones until the 1980s. It consists of granules of carbon compressed into a "button". DC power runs through it, and as a diaphragm vibrates and pushes against the carbon it changes the resistance of the carbon. A signal is generated in the circuit which can be converted to higher voltages with a transformer, which made it great for telephone transmission.

[MeruvaKodandaSuraj]

Thanks for the wonderful and informative video!

[beeforsalad]

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