Electronic telegraph relay including silicon controlled rectifiers responsive to binary input signals

摘要

1,070,293. Semi-conductor switching circuits. TELEPHONE MANUFACTURING CO. Ltd. July 22, 1965 [Aug. 4, 1964], No. 31669/64. Heading H3T. A circuit for reversing the direction of current in a load comprises two silicon controlled rectifiers SCR1, SCR2 selectively made conductive by signals at X1, Y1 and provided with commutating capacitors C1, C2 between their respective anodes and cathodes. The Specification describes circuits for replacing conventional polarized electromagnetic relays used in telegraphy. As described, bipolar signals are fed to a diode gate (Fig. 2, not shown) so as to steer the output of an oscillator to one of a pair of transformer(rectifier circuits in dependence on the polarity of the incoming signal. The outputs of the rectifier circuits are fed to terminals X1, Y1 so that the appropriate SCR is turned on to connect the magnet coil PH of a printer via an artificial line EL to either positive or negative supplies Tg in dependence on the polarity of incoming signal. In Fig. 3 (not shown) the iricoming signals are fed via a longtailed pair of transistors to a diode bridge which selectively feeds the output of a pulse generator to terminals X1 or Y1.