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Electromagnetism

What is a Microphone?

A microphone is a device which
generates electricity from sound waves.

How does a Microphone Work?

The microphone works by producing a small induced voltage
in a coil of wire when sound waves hit a diaphragm.
It is very similar to a loudspeaker in reverse with
a diaphragm instead of a paper cone.
This type of microphone is called a moving coil microphone.

Microphone

The sound waves strike the diaphragm and move it
backwards and forwards at the same frequency as the sound
(like the way the ear drum is moved inside the ear). The
moving diaphragm moves the coil backwards and forwards which
induces a changing current at the same frequency as the sound.
This changing current (called the signal) can be used for
recording or the signal can be sent to an amplifier
which makes the signal big enough to drive loudspeakers.

The loudspeaker converts the signal back into the original sound.

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