Patent GB-858338-A (GB)
Title: Improvements in magnetic core logical devices
IPC: H03K17/82
Filed: 1957-08-22
Abstract: 858,338. Magnetic pulse-gating circuits. INTERNATIONAL BUSINESS MACHINES CORPORATION. Aug. 22, 1957 [Aug. 22, 1956], No. 26499/57. Class 40 (9). [Also in Group XXXV] A magnetic core device capable of storage of information is used as a logical device. The core may be rectangular or circular as shown in Fig. 2, and is provided with an "input" aperture M which divides the flux path into two. It may also be provided with an " output " aperture N and the apertures may be longitudinal as shown or radial. The apertures are linked by various windings of the types shown by A, B, C, S, R (input windings) and X, Y, Z. (output windings) to provide various embodiments. In principle, the device depends on the fact that with a main flux established round the core establishment of a localized flux round the aperture M causes the main flux to assume a kidney shape with reversal of the direction of the radially innermost flux lines and the consequent production of a substantial voltage in an output winding. Logical arrangements.-Fig. 4 shows a device to perform an " exclusive or " function. After a flux is set up by winding R, a signal on either of the windings A, A<SP>1</SP> causes " kidneying " of the flux to provide an output signal since A and A<SP>1</SP> are oppositely wound simultaneous signals cancel and no output results. For an " inclusive or " device two similarly wound windings A are used when simultaneous pulsing gives an output. In modifications each winding A and A<SP>1</SP> links an individual aperture to avoid interaction between windings (Fig. 5, not shown) and windings of the B-type are used poled to oppose the remanent flux in the core section outermost from the aperture M (Fig. 6, not shown). A further indicating output pulse may be obtained at any subsequent time by pulsing winding R and re-establishing the main flux. Fig. 9 shows a modification of an " inclusive or " device in which two C-type windings are associated with two input apertures. In the device of Fig. 10, each winding D creates local fluxes round apertures M 1 , M 2  so that with current flow as shown the device acts as an " inclusive or " device, and with one current reversed cancellation occurs to provide an " exclusive or " device. In a modification providing only an " inclusive or " function, two pairs of apertures are provided, each winding linking only one pair to avoid interaction. The provision of an output aperture enables all previous embodiments to be used with a Z- type output winding. Also by short-circuiting the inner flux section by a winding Z and a switch j, Y-type output windings may be used (Fig. 13). A logical " and " device is illustrated by Fig. 15 where two input windings of the B and C-types are provided with an output winding of the X or Y-type. Fig. 17 shows an " and not " device in which set windings S establishes a flux opposite to that of reset winding R so that pulsing R reverses the flux to give a full output, but if in the interim either or both windings A are pulsed a half-value output is obtained. Other " and not " devices are obtained by providing set windings on the embodiments of Figs. 4-11. An inverter or "not" type device is disclosed in Fig. 20, wherein pulsing the reset winding R after the flux has been set by winding S only results in a pulse if no signal pulse occurred in winding A. An " inhibit " function whereby an output pulse is obtained unless a signal pulse is applied is performed by the device of Fig. 22 (not shown). Specification 789,668 is referred to.