GB824036A - Improvements in magnetic amplifier circuits - Google Patents

Abstract

824,036. Magnetic amplifiers. SPERRY RAND CORPORATION. May 9, 1957, No. 14743/57. Class 40 (9). Pulses of one polarity from an alternating pulse source are applied to a winding on a magnetic core by way of a rectifier, a source of D.C. being connected to the winding to magnetize the core in an opposite sense during periods when the rectifier is cut-off, and an input signal being selectively applied to inhibit magnetization by the pulses of one polarity so as to inhibit an output signal derived from the reversal of magnetization by the D.C. source. Alternating current of square wave form as shown at A of Fig. 3 is applied to terminal 24 of Fig. 2 and during negative half-cycles energizes winding 21 of core 20 over rectifier D1 and resistor R2. During this half-cycle a rectifier D2 parallel to R2 is disconnected and a source of constant voltage +V is prevented from energizing the winding 21 over the highvalued resistor R1. During the next half-cycle of alternating current rectifier D1 is disconnected and the winding 21 is energized from the source +V over diode D2 to drive the core in the opposite direction. In the absence of a signal on terminal 25 of input winding 22 the alternating source and the source +V switch the core backwards and forwards between its saturated states and in response to switching by the source +V an output is induced in output winding 23 which over diode D4 energizes a load RL. If, however, during a negative halfcycle of the alternating source, the input winding is energized to prevent the core being switched by means of the waveform shown at C in Fig. 3, no output is produced in the following half-cycle as shown at B in Fig. 3. Should the input to winding 22 be greater in its effect than the magnetization produced by the source +V, a source of blocking pulses as shown at D in Fig. 3 is applied to terminal 27 of the output winding to prevent it being coupled to the input winding. Instead of using a separate load winding 23, the load may be connected in parallel with the winding 21 which has a high impedance when the core is switched by the source +V and therefore allows the load to shunt current, but has a low impedance in the half-cycle after an input to winding 22 and therefore shunts current away from the load which gives no significant output. This connection of the load is shown in Fig. 5 where the input winding is also dispensed with and a clamp circuit, comprising D.C. sources - E and - V with resistor R7 and rectifier D13, is connected to winding 21 over rectifier D11. An input pulse coincident with a negative half-cycle of the alternating source charges a capacitor C which unblocks rectifier D11 to hold the upper end of winding 21 at earth potential and prevent the core being switched.