Abstract: An automatic bias control for substantially eliminating crossover distortion in power amplifiers. The bias current is measured in terms of a voltage developed across a resistor in series with the output device. This voltage is processed by a bias control function consisting of a summing circuit, a peak minimum detection circuit, a voltage reference and a mixing circuit added to the output stage in a controlled feedback loop. Elements of these circuits include operational amplifiers. The bias control system is compatible with other feedback loops in the amplifier so that transient and drift control are achieved and no instabilities are introduced. The bias control operates in the presence of widely varying high level signals.