microphone

A microphone (colloquially called a mic or mike; both pronounced /ˈmaɪk/) is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. Microphones are used in many applications such as telephones, tape recorders, karaoke systems, hearing aids, motion picture production, live and recorded audio engineering, FRS radios, megaphones, in radio and television broadcasting and in computers for recording voice, speech recognition, VoIP, and for non-acoustic purposes such as ultrasonic checking or knock sensors.
Most microphones today use electromagnetic induction (dynamic microphone), capacitance change (condenser microphone), piezoelectric generation, or light modulation to produce an electrical voltage signal from mechanical vibration.
Both Thomas Alva Edison and Emile Berliner filed patent applications for the carbon microphone, in March and June 1877 respectively. After a long legal battle, Edison emerged the victor, and the Berliner patent was ruled…