A device that increases the amplitude or power of a signal. It is an important component for processing signals in automated technology tools. The amplifier's amplification effect is achieved by controlling the energy with the input signal, and the power consumption required for the amplification is provided by the energy source. For a linear amplifier, the output is the reproduction and enhancement of the input signal. For a non-linear amplifier, the output is a function of the input signal.
Amplifiers are divided into mechanical amplifiers, electromechanical amplifiers, electronic amplifiers, hydraulic amplifiers, and pneumatic amplifiers according to the physical quantities of the signals processed. Among them, the most widely used are electronic amplifiers. With the popularization of jet technology (see jet components), the application of hydraulic or pneumatic amplifiers has gradually increased. Electronic amplifiers are further divided into vacuum tube amplifiers, transistor amplifiers, solid-state amplifiers, and magnetic amplifiers according to the active devices used. Among them, transistor amplifiers are the most widely used. Transistor amplifiers are often used for signal voltage and current amplification in automation instruments. The main forms are single-ended amplification and push-pull amplification. In addition, it is often used for impedance matching, isolation, current-voltage conversion, charge-voltage conversion (such as charge amplifiers), and the use of amplifiers to achieve a certain functional relationship between output and input (such as operational amplifiers).