Improvements in electrical delay actions or circuits depending upon the operation oflight-sensitive devices

摘要

391,797. Controlling apparatus by light. POOK, H. W., 112, Beckenham Lane, Shortlands, Kent, and RADIO V I S 0 R PARENT, Ltd., 28, Little Russell Street, London. Nov. 3, 1931, No. 30441. [Class 40 (v).] In a delay-action circuit, a light-sensitive cell 1 and a resistance 2 in series are connected to a relay 9, Fig. 1, through a condenser 7, and an additional resistance 11 is brought into circuit by the relay to vary the effective resistance of the cell or the resistance 2. The relay is in the anode circuit of a thermionic valve 6 with its grid connected through the condenser to the junction 5 of the cell and the resistance 2. The resistance 11 is in series or shunt, Fig. 2 (not shown), with the resistance 2. The resistance 2 may be in two sections and the circuit operated by short-circuiting one of them, Fig. 3 (not shown). As shown in Fig. 4, the relay 20 is connected directly through the condenser to the junction 5.