Improvements in or relating to electrical timing devices

Abstract

Abstract 408,624. Valve circuits. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London, and ESPLEY, D. C., c/o General Electric Co., Wembley, Middlesex. Oct. 8, 1932, No. 28066. [Class 40 (v).] An electrical timing circuit for automatic traffic signals and the like is supplied with A.C. and comprises a thermionic triode, the anode circuit of which includes a relay A for effecting the desired control, and also a condenser C2 in one position of a relay D (not shown) which controls contacts d1, d2. With the relay D de-energized, the condenser C2 is charged from A.C. supply through the triode because contact d2 is closed and switch d1 connects the condenser C2 in the anode circuit of the valve. When the relay D is energized the condenser C2 is connected to the grid of the triode and contact d2 is opened. The charge on C2 leaks away over the resistance R2 and, after a predetermined time, the anode current rises sufficiently to operate the relay A which remains energized until the relay D is again operated. The device may be arranged to repeat the cycle indefinitely by controlling the contacts d1 from the relay A and contacts d2 from a relay in the circuit of the condenser C2. In a modification, the condenser C2 is connected in series with the resistance R2 across the resistance R1 and is paralleled by a resistance under the .control of a switch operated by the relay A. This arrangement functions continuously as an impulser, the impulses being supplied to external circuits by contacts on the relay A. A relay E (not shown) may be arranged to control a switch e1 in the circuit of the discharging resistance R2. Specification 402,750 is referred to.

Inventors

No inventors recorded.

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