…an electronic device for increasing the amplitude of electrical signals, used chiefly in sound reproduction…
…a device designed to amplify the wide range of frequencies present in video signals and deliver the signal to the picture tube of a television set…
…an amplifier with high gain and high input impedance (usually with external feedback), used especially in circuits for performing mathematical operations on an input voltage…
…an electronic device that amplifies a very weak signal, for example from a microphone or pickup, and transmits it to a main amplifier…
