carbon microphone

British  

noun

1. a microphone in which a diaphragm, vibrated by sound waves, applies a varying pressure to a container packed with carbon granules, altering the resistance of the carbon. A current flowing through the carbon is thus modulated at the frequency of the sound waves

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Example Sentences

Mr. Peer, armed with new portable technology — including a type of carbon microphone that made sound recordings considerably truer — traveled to Tennessee to record what he called the area’s “hillbilly music.”

From New York Times

As this would cause obvious communications problems, the masks were designed with a carbon microphone attachment, designed to make conversations easier.

From BBC

As he put it, “In their minds I am speaking into a circular, spring-suspension carbon microphone.”

From New York Times

A careful examination of the opinions of scientific men given in the telephone cases--before Lord McLaren in Edinburgh and before Mr. Justice Fry in London--leads me to the conclusion that scientific men, at least those whose opinions I shall quote, are not agreed as to what is the action of the carbon microphone.

From Project Gutenberg

All the above named scientific men agree that variations of a current passing through a carbon microphone are produced by pressure of the carbons against one another, and they also agree that a jolting motion could not be relied upon to reproduce articulate speech.

From Project Gutenberg