Abstract: A class BC power amplifier having a symmetrical push-pull preamplifier and a pair of symmetrical branches coupled, respectively, to the outputs of said push-pull preamplifier. Each of said branches includes a first power stage, operating in class B, coupled to the output of said branch, a control stage coupled to the respective output of said push-pull preamplifier for controlling said first power stage, a second power stage, operating in class C, coupled to said first power stage, and a first comparative stage coupled between said control stage and said branch output for controlling said second power stage. Each branch of said power amplifier further comprises a third power stage, operating in class C, also coupled to said first power stage, and a second comparative stage coupled between said control stage and said branch output for controlling said third power stage.

Abstract: The invention provides a class BC power amplifier which permits control by a circuit with a transistor, which circuit, besides its control functions, effects also a protection of the end stage from transient processes caused by the inductive character of the load. The efficiency of the amplifier is not lowered, but it remains sufficiently high and corresponds to the class BC. The use of an output transformer is not obligatory.