Amplifier

The word amplifier (sometimes called an amp) usually refers to an electronic amplifier. Electronic amplifiers make a signal from a radio or electric musical instrument (such as an electric guitar or an electric bass guitar) louder and stronger. Amplifiers are also hidden in any electronic thing that makes sound with loudspeakers. This includes televisions, radios, computers, and mp3 players, to name a few.

Amplifiers ability to use low impedance speakers may vary. Typical impedance is 8 ohms.

Classification can be done by current loss when amplifier is on but does not get signal. Example: A-class amplifier takes more current without signal than B-class amplifier but A-class amplifier have smaller distortion.

There is also several distortion types.