GB795528A - Improvements in or relating to magnetic amplifiers - Google Patents

Abstract

795,528. Magnetic amplifiers. REMINGTON RAND, Inc. Nov. 18, 1954 [Dec. 23, 1953], No. 33450/54. Class 40 (4). Magnetic amplifiers, which are set to a level of magnetization dependent upon an input voltage in one half-cycle of a control voltage and are reset to produce an output in the following halfcycle, are connected in cascade and an indication of a change in value of the input signal is obtained by taking the difference between the output of different stages of the cascade connection. In Fig. 1a three magnetic amplifiers are connected in cascade, amplifier 101 being set by a control voltage Ez when this is sufficient to overcome the input voltage Ec and cause diode 31 to conduct. During the next halfcycle a control voltage Eac drives the core to saturation and produces an output voltage E<SP>1</SP>c which is used to set the second amplifier 103 which has a gain of unity. When amplifier 103 is reset in the next half-cycle by voltage E<SP>1</SP>ac its output E<SP>11</SP>c is used to set the third amplifier 105 which also has a gain of unity. The output Ek of amplifier 105 is produced by voltage E<SP>11</SP>ac in the next subsequent half-cycle and corresponds in value to the output E<SP>1</SP>c of amplifier 101 one full cycle earlier. A subtracting circuit 161 measuring the difference Eo between the outputs E<SP>1</SP>c and Ek therefore registers the difference between time integrals of the input voltage Ec taken during half-cycles of the control frequency spaced apart by one cycle. The outputs E<SP>1</SP>c and Ek of amplifiers 101 and 103 are out-of-phase so that a difference of time integrals of the input voltage separated by a half-cycle cannot conveniently be taken. However, by replacing amplifiers 101 and 103 by push-pull connected amplifiers (see Fig. 2, not shown), outputs E<SP>1</SP>c and E<SP>11</SP>c occur during each half-cycle and a difference may be taken.