Carbon Microphone

The carbon microphone is also known as carbon button microphone, button microphone, or carbon transmitter, is a transducer that converts sound to an electrical audio signal. It consists of two metal plates that are divided by granules of carbon where one plate is very thin and faces outward, acting as a diaphragm. When sound strikes the moveable plate, it vibrates the carbon, changing the resistance in the carbon. The change in resistance is read by electrical equipment to convert the sound into an electrical signal.