Alternating current control of the half-wave bridge magnetic amplifier

RECENT developments in transistors indicate great promise for a high-gain, high-power-output servo amplifier consisting of a transistor preamplifier in combination with a fast-response half-wave bridge magnetic power amplifier. Existing literature on this type of magnetic amplifier does not discuss certain problems inherent in applying this device as an output stage fed by an a-c pre-amplifier.1,2 Among these are the problems of reduced output as a result of large control signals, and variation in operation caused by different types of load.