The amplifiers are classified by a voltage signal or power signal based on the applied signals. This should be accomplished depending on the input values, and output values produced. The key focus of the amplifier is to increase the input signal frequency to reach the maximum output potential. The power amplifiers are classified into the following types based on the form of the output system that is associated. 

Audio Power Amplifiers

These amplifiers are used in the headphones, radio devices and transmitters. These are used to collect the distorted signal from a set of voltage amplifiers and then have adequate power to support the loudspeakers. 

Radio Frequency (RF) Power Amplifiers

Radio frequency amplifiers are modified amplifiers in which a tuned circuit system regulates the operating frequency. Depending on the function of the amplifier, this circuit may or may not be controlled. The bandwidth may also be fairly wide or narrow-based on usage. This form of amplifier is also used for long-distance transmission wirelessly. The propagation of these signals requires amplification such that the signal quality can be increased and the data can be transmitted over long distances. Such amplifiers are more generally used for processing FM signals. 

DC Power Amplifiers

These are used to improve the DC (0 Hz) voltages or high-frequency signals where the DC signal intensity is a significant parameter. They are often used in many electrical control systems and measurement instruments. These amplifiers are used to enhance the Pulse Width Modulated signals (PWMs). This pulse width is modulated to allow rational signals to operate on the motors.