GB933228A - Circuits employing square loop cores - Google Patents

Abstract

933,228. Circuits employing bi-stable magnetic elements. JOSEPH LUCAS (INDUSTRIES) Ltd. Oct. 11, 1960 [Oct. 12, 1959; July 1, 1960], Nos. 34460/59 and 23044/60. Class 40 (9). In a circuit, Fig. 2, comprising a core C having a substantially square hysteresis loop, switches T1, T2, T4 are connected to input windings L1, L2, L4 respectively, and the arrangement is such that, with a D.C. source connected across capacitor C1, when switch T2 is conductive current flows through winding L2 to magnetize the core in one direction and when switch T1 is conductive current flows through winding L1 to apply a magneto-motive force to the core in the opposite direction, an output appearing in an output winding L3 whenever the remanent state of the core changes. Current flowing through input winding L4 when switch T4 is conductive, applies a magneto-motive force to the core in the same direction as current flow through winding L1. In one arrangement, signals applied to terminal S2 are clock pulses and signals must be applied simultaneously to terminals S1 and S4 (which signals must be out of phase with the signals applied to terminal S2) to produce an output, current flowing through either winding L1, L4 alone being insufficient to change the remanent state of the core. In another arrangement, the circuit is such that signals applied to either terminal S1 or S4 result in an output in winding L3, provided that the remanent state of the core is correctly set. In a further arrangement, Fig. 1 (not shown), the input winding L4 and switch T4 are omitted. Clock pulses are applied to terminal S2 and the circuit produces an output in the form of a train of pulses provided that pulses are applied to terminal S1 out of phase with those applied to terminal S2. The switches may be transistors, cold cathode tubes or other equivalent vacuum or semi-conductor devices. The purpose of capacitor C1 is to minimize the risk of overloading the source of supply when the source supplies power to a plurality of circuits such as those shown. Resistor R2 is so chosen that the capacitor charges slowly when the switches are non- conductive.