Compensating for the quiescent current in multistage magnetic amplifiers

WHEN a single saturating reactor is used as a magnetic amplifier the output current is not zero when there is no d-c input. In the absence of any d-c saturating excitation there is a small quiescent current Io. The application of a d-c signal causes the output to increase from this smaller value, Io, to a larger value Is. Under the conditions which give rise to maximum gain, the value of Io is usually a substantial percentage of that of Is, as for example in the order of 30 per cent.