Question

on what principle does a mic work?

Answer 1

A microphone is a kind of device that converts acoustical pressure waves (or sound, which is mechanical energy) into electrical energy or signals. All microphones have a diaphragm, membrane, or other mechanical element in them that vibrates sympathetically in response to the arriving acoustic wave fronts. This mechanical element acts on the electrical element to generate electromagnetic energy (voltage). The actual mechanism used to make the conversion from mechanical energy to electrical energy will vary from mic to mic. Let's have a look at one kind.

We see some microphones that have a diaphragm with a coil of wire attached to that diaphragm. Inside the coil is a stationary magnet. The sound energy moves the diaphragm, which moves the coil (with the stationary magnet inside it). The movement of the coil in the fixed magnetic field generates an electrical signal in the coil that "corresponds" to the sound that created it. The signal may then be sent via wires to an amplifier. There are other types of microphones, and for information on them, follow the link below.