How Does A Microphone Works ?

A Microphone is a device which transforms sound waves into electrical signals. These signals can , then be broadcast through the air or sent over to far-off points where they can again be transformed back into sound. Microphones can be classified into two groups , depending upon how they react to sound waves. They are pressure type and velocity type. The pressure type Microphone has a thin metal plate known as diaphragm. This is stretched like a drumhead inside a rigid frame. 

The diaphragm is a portion of the electrical circuit. When sound waves hit the diaphragm , it begins to vibrate at the same rate as the sound waves. These vibrations make corresponding electric signals by converting electric current that flows through the circuit. In the velocity type microphone , the vibration varies with the capacitance of the condenser.