Patent GB-706736-A (GB)
Title: Improvements in or relating to electrical storage devices
Inventor: BOOTH ANDREW DONALD
IPC: H03K23/76
Filed: 1952-01-03
Abstract: 706,736. Digital electric calculating-apparatus. BRITISH TABULATING MACHINE CO., Ltd. Jan. 3, 1952, No. 260/52. Class 106 (1). [Also in Group XXXIX] A storage device, e.g. in a digital computer, for data represented by electric pulses, comprises a pair of magnetic circuits possessing appreciable remanence, the presence and absence of stored data being represented respectively by first and second combinations of static magnetic states of the circuits, and a pulse input, a shift and an output winding for each circuit, each pair of windings being so connected that the application of a pulse to the shift winding' induces in the output windings voltages which substantially cancel or not according to whether the circuits are in a second or first combination of states respectively. Fig. 3 shows balanced devices, for storing binary numbers, which enable magnetic material e.g. powdered iron, having a non-rectangular hysteresis curve, Fig. 4, to be employed. Each device comprises two toroid cores 19, 20, on which are wound input, output and shift coils 25, 23, 24 respectively. The shift coils 24 are connected in series opposition so that a pulse applied thereto will bring the states of the cores 19, 20 respectively to opposite points 14', 12' on the hysteresis curve. This is the " 0 " or "no registration" condition. An input pulse, representing " 1 ", applied to coils 25 will bring core 20 to point 14' and the next shift pulse will cause this core to return to point 12' through 15', while core 19 moves to 13' and back to 14' thus producing an appreciable net output pulse in coils 23 proportional to the difference (x-y). If, however, a shift pulse is applied when the storage device is registering " 0 ", core 20 will move from 12' to 15<SP>1</SP> and back so that the net output pulse is proportional to (y - z) which is theoretically zero. As shown, the devices are connected to form a shifting register through link circuits, each including rectifiers 28, 30 and a resistance 31, which connect the output coils of one device to the input coils of the next. Shift pulses are applied alternately to lines 26, 27 to shift along the pattern of " 0 and " 1 " registrations. In a modification, " 0 " is represented by a pulse of opposite polarity to " 1 ", and for the " 0 registration condition both cores 19, 20 are brought to point 12', so that when a shift pulse returns the device to the " no registration " condition from either the " 0 " or " 1 " condition an output pulse will be produced. The link circuit shown is replaced by a gating device, e.g. comprising a balanced arrangement of two magnetic cores, which allows an effective connection between coils 23, 25 only when a shift pulse occurs. The input and output coils, instead of the shift coil, may be connected in series opposition, and the two toroids may be replaced by a figure-of-eight the input or shift coils being wound on the part thereof common to the two magnetic circuits. A known shifting register also is described and shown employing storage devices each comprising a single core with three coils wound thereon.