Amplifier
An amplifier is a device which changes a small movement into a larger movement. However, in general the most common and useful amplifiers actually use a small amount of energy to control a larger amount of energy. Furthermore it is of significant advantage if the amplified output is in a linear relationship with that of the input. This relationship is known as the gain of the amplifier.See also: low noise amplifier.
The most common type of amplifier is the electronic amplifier, commonly used in radio and television transmitters and receivers, hi-fi units, microcomputers and other electronic digital equipment, and guitar and other instrument amplifiers.
Another type of amplifier is the fluidic amplifier, based on the fluidic triode.