Video: Dynamic microphone

The microphone enables us to convert a mechanical vibration into an electrical signal.

Its function is symmetrical to that of a loudspeaker in the chain of transmission. It is thus most often located at the beginning of this chain, at the point of acquisition of data.

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In a dynamic microphone, there is a mobile membrane called the diaphragm (…)

a coil of copper wire, also mobile,  as it is attached to the diaphragm (…)

and a permanent magnet, which remains fixed.

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The principle of functioning rests on the law of electromagnetic induction:

The rapid displacement of the coil in relation to the magnet’s field induces a voltage at the coil’s poles.

Since the mechanical vibration mirrors the sound vibration, the electrical signal induced in the coil will also mirror the sound vibration.

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This type of microphone is easy to manufacture. It does not require any external source of energy and is quite robust, notably for use onstage.

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The inertia of the coil-diaphragm couple, on the other hand, makes it less sensitive to high pitches than is the electrostatic microphone.