The microphone is a transducer that converts sound into electrical signals. Microphones are used in many applications such as telephones, tape recorders, hearing aids, concerts and in radio and television.

The microphone converts mechanical vibrations in the audible range (at frequencies from 20Hz to 20kHz - in the air, water or solid material) into an electrical signal. In most microphones in use sound waves are converted into mechanical vibrations by a thin flexible diaphragm and then converted into an electrical signal through coil or by charging and discharging of a capacitor.