Protection circuit for output stage of low frequency amplifiers

摘要

An electronic cut out for the protection of output stage transistors of a low frequency amplifier comprises means for producing first and second direct voltages proportional to the output alternating voltage and the collector alternating current of the output stage transistors respectively, means for comparing these voltages and igniting a thyristor if the second voltage exceeds a predetermined threshold, the thyristor being connected to short circuit the low frequency signal to earth prior to its arrival at the output stage transistors when the thyristor is ignited.