A microphone is a device that converts sound waves into an electrical signal. It is used in many applications such as telephones, hearing aids, public address systems, motion picture production, live and recorded audio engineering, sound recording, two-way radios, megaphones, and radio and television broadcasting. Microphones can be standalone or embedded in devices such as headsets and telephones. There are several types of microphones that employ different methods to convert the air pressure variations of a sound wave to an electrical signal. The most common types are:
- Dynamic Microphone: Uses a coil of wire suspended in a magnetic field.
- Condenser Microphone: Uses the vibrating diaphragm as a capacitor plate.
- Contact Microphone: Uses a crystal of piezoelectric material.
Microphones are also designed on the basis of directionality, besides the type of device. For example, omnidirectional microphones are capable of picking up all sounds in an area, but they are unable to focus on a particular subject with background noise. Bidirectional, directional, and shotgun microphones are beneficial for an interview. However, two unidirectional devices can be used to record a stereo signal. Microphones are used in computers for recording voice, speech recognition, VoIP, and for other purposes such as ultrasonic sensors or knock sensors.
