Microphone

A microphone is a 

Operation

[2] A microphone uses an electromagnetic coil to move in/out around a permanent magnet by controlling a current running through it. 

The rotor's rotational movement and a microphone (or speaker)'s back and forth are due to the polar interaction between the electromagnetic movement of the coil and the permanent magnet continuously attracting and repelling each other.

References

• [1] Wikipedia

• [2] How Do Hall Effect Sensors Work? | element14 presents

  • [2.1]

• [3]