An amplifier is an electronic device or circuit that increases the strength of a signal—whether it’s voltage, current, or power—without changing its essential characteristics (like frequency or waveform).
Used to increase the power of a signal, amplifiers comprise multiple types, including power, transistor, operational, fully differential, video, microwave and more. Applications for amplifiers are varied but are normally used in Audio and Video applications. One can find amplifiers to boost or amplify the signal to a consumable level.