Microphone

Microphones are devices used to record sound by converting sound, which is variations of air pressure in air, into electrical variations. There are a number of ways a microphone can do this. The first microphone was purely mechanical. Variations in air pressure from sound would vibrate a diaphragm, which would in turn vibrate a needle. The needle would etch a pattern into a piece of foil. To play back the sound, the needle was run back over the pattern and the diaphragm vibrates back the sound. Modern microphones use the same principle, except it’s done electronically. A microphone is also used in events where sound amplification is required, such as board meetings or in football stadiums.