| 摘要 |
1,038,454. Electric selective signalling. BRITISH TELECOMMUNICATIONS RESEARCH Ltd. Dec. 18, 1963 [Dec. 20, 1962; Feb. 13, 1963], Nos. 48165/62 and 5891/63. Heading G4H. [Also in Division G1] Solar radiation is converted to electrical energy to charge a capacitor until a Zener diode D2 (not shown) conducts thus biasing a transistor to initiate a switching operation. The switching operation feeds a pulse to a counter which, when a predetermined count is reached, delivers water to an irrigation network or sounds an alarm The electrical energy also charges a battery powering the circuit.
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