| 摘要 |
<p>890,851. Bi-stable circuits using transistors or valves. STANDARD TELEPHONES & CABLES Ltd. Nov. 6, 1959 [Nov. 7, 1958], No. 37709/59. Class 40(6). In a bi-stable circuit of the type comprising two alternatively conducting active electronic elements, one of two windings oppositely wound on a square loop core is included in the circuit of each element so that when the supply voltage is removed from the circuit the information stored in the bi-stable circuit remains stored in the core and when the supply is replaced the bi-stable circuit is restored its previous condition. Fig. 1 shows a transistor bi-stable circuit in which each collector circuit includes one of the two reversely wound windings W1, W2 of a square loop core K. When transistor Tl is conducting the current through winding W1 saturates the core in one direction. Accordingly, if the supply is interrupted and then restored, current will quickly build up through winding W1, since for currents in this direction the winding has no incremental inductance. Current will only slowly build up in winding W2 since winding direction is such as to tend to set the core to its other state of saturation and accordingly the winding has a large incremental inductance. The transistor T1 will thus again become the conducting transistor. Similarly if transistor T2 is non-conducting before the interruption it will restore to conduction after the interruption. In an alternative circuit (Fig. 2 not shown) further windings on the core K are connected in series with the base input circuit of the transistors so as to hold the previously non-conducting transistor in this state when the supply is restored. The transistors may be replaced by valves.</p> |
