Linear amplifier

A linear amplifier is an electronic circuit whose output is proportional to its input, but capable of delivering more power into a load.

Linearity refers to the ability of the amplifier to produce signals that are accurate copies of the input, generally at increased power levels.

Load impedance, supply voltage, input base current, and power output capabilities can affect the efficiency of the amplifier.

Therefore, class-AB power amplifiers or other variations are used with some suitable form of linearization schemes such as feedback, feedforward or analog or digital predistortion (DPD).

[2] Some commercially manufactured one to two kilowatt linear amplifiers used in amateur radio still use vacuum tubes (valves) and can provide 10 to 20 times RF power amplification (10 to 13 dB).

[5][6] The output stages of professional AM radio broadcast transmitters of up to 50 kW need to be linear and are now usually constructed using solid state technologies.