GB1048574A - Pulse-doubling relay circuit - Google Patents

Abstract

1,048,574. Relay switching systems. STANDARD TELEPHONES & CABLES Ltd. Sept. 16, 1963 [April 2, 1963], No. 36339/63. Heading H2H. An electromagnetic relay J is operated at twice the rate of a control relay by connecting the contacts st1, st2 of the latter, the winding of relay J and a capacitor C across a D.C. supply as shown in Fig. 1. Each operation of contacts st1, st2 produces a current pulse through members J, C causing temporary operation of the relay contact i. If the control relay has only one contact, e.g. st1, the circuit is completed by two resistors, each in series with a rectifier if necessary, the resistors having a common connection to the supply and individual connections to the members J, C, respectively, Fig. 1(a) (not shown). Members J, C and a single control contact st may be series-connected across the supply, with a discharge resistor in parallel with the J, C, combination, Fig. 2 (not shown). This arrangement may be modified to make the relay operating times equal by inserting between members J, C a parallel combination of a resistor and a suitably poled rectifier, Fig. 2(a) (not shown). In Fig. 3 the contacts a, b of two relays A, B (not shown), control a relay K, operation of contact a energizing a bias winding through an adjustable resistor R3, and operation of contact b causing charge or discharge of the capacitor C through one or other of the two relay operating windings to produce temporary operation of the relay for a time dependent on its polarization.