GB1055894A - Magnetic logical device - Google Patents

Abstract

1,055,894. Circuits employing bi-stable magnetic elements. ENGLISH ELECTRIC CO. Ltd. Aug. 7, 1964 [Aug. 9, 1963], No. 31497/63. Heading H3B. [Also in Division H1] A magnetic logical device comprises an annulus of rectangular loop magnetic material the inner perimeter of which defines a minor aperture and the annulus having three major apertures which are disposed at substantially equal intervals around the annulus. In the arrangement of Fig. 1 performing the AND function a pulse in reset winding 21 sets up a flux pattern in parts 15, 16 which is clockwise with respect to minor aperture 11 and a flux pattern in part 17 which is counter-clockwise. When a priming pulse is applied to prime winding 22 such as to tend to set up a flux acting around the minor aperture 11 in a clockwise direction the flux paths around the major apertures 12, 13, 14 will not be affected and no output signal will be induced in output winding 23. If, however, input signals are applied to input windings 24, 25 so that the flux directions around apertures 12, 13 are simultaneously clock-wise then the field caused by the priming current pulse will set up a flux round aperture 11 in a clock-wise direction. On the occurrence of the next reset pulse the flux in part 17 will be reversed and an output signal will be induced in output winding 23. If one of the input signals is missing the priming current cannot cause the flux to act round aperture 11 in a clockwise direction so that no output signal is produced by the subsequent reset pulse. To prevent back flow of data when more than one device are connected together a hold winding is wound on part 17 which sets up a field acting in a clockwise direction around aperture 14 when multi-aperture core 23A linked with the output winding 23 is reset. Alternatively a second prime winding may be linked with the input aperture of the following device. Fig. 2 shows a HALF-ADDER, and includes a further output winding 26 wound in series opposition round parts 15, 16. As in the case of Fig. 1, an output signal is induced in output winding 23 only when input signals A, B are applied simultaneously to windings 24, 25, which signals reverse the flux set round apertures 12, 13 and reverses the direction of the flux in 17. The output signal at winding 26 represents the EXCLUSIVE-OR function of the input signals A#B + #AB and the output signal at 23 may be defined as AB. By using combinations of input windings the output signal can be made to depend upon more than two variables. Non- destructive read-out of the data in the device of Fig. 1 may be achieved by energizing prime winding 22 with an alternating current of limited amplitude.