| 摘要 |
<p>1,013,511. Circuits employing bi-stable magnetic elements. DECCA Ltd. Jan. 17, 1964 [Jan. 31, 1963], No. 3974/63. Heading H3B. One or a group of a plurality of loads 10 is selected by means of an arrangement including rectangular-loop magnetic cores 2 which are switched by current in an interrogate winding 3 to induce an e.m.f. across drive windings 5 thereby reverse-biasing diodes 8, except in one selected load circuit or group of circuits whose associated core 2 is prevented from switching by energization of a clamp circuit 12 which provides a low impedance or short-circuit across winding 7. In order to provide a further pulse to the corresponding one of a second group of loads 11 additional windings 4, 6 are provided. All the cores 2 except the selected one are in a " set " state after energization of winding 3, and subsequent energization of oppositely wound winding 4 switches the cores back. Again diodes 9 in the non-selected circuits are back-biased. The selected core is already reset so does not switch and load current flows to a load 11. If two-phase operation, with windings 4, 6, and loads 11, is not used a resetting pulse is applied to the cores between each operation. A single pulse source may be used for the interrogate windings and for the load. To prevent spurious currents in unselected loads after switching is complete the pulses from source 14 may be terminated before switching ceases. The device may be extended to larger numbers of loads by utilizing the " split " decoder principle (Fig. 2, not shown), in which a one-out-of-three circuit is connected to first ends of the loads, and a oneout-of-two circuit is connected to the other ends. Alternatively, a "tree" decoder is suggested (Fig. 3), in which three consecutive one-out-of-two selections are made. The two techniques may also be used together. The clamp circuits may consist of transistors, providing a high impedance, or open circuit when not energized.</p> |
