| 摘要 |
1,189,294. Vehicle electrical systems. JOSEPH LUCAS (INDUSTRIES) Ltd. 25 Aug., 1967 [9 Sept., 1966], No. 40307/66. Heading H2H. A warning lamp circuit for use in a batterycharging system in which the battery 12 is charged from a generator 15, e.g. a dynamo or alternator rectifier, incorporates a capacitor 22, which may be charged from the battery when the ignition switch 13 is closed, and a transistor 16 whose base emitter circuit will be energized by the voltage across the capacitor through a diode 19, so that current passes through the transistor to illuminate the warning lamp 17 when the capacitor is charged, which is when the generator is not producing an output. When the generator is producing an output, a D.C. or square-wave signal is applied to the terminal 24 so as to maintain the capacitor discharged and consequently prevent illumination of the warning lamp. A further arrangement comprising a Zener diode 18 enables the lamp to be illuminated when the generator output is excessive, e.g. on failure of the voltage regulator. The Zener breaks down so that the generator voltage is applied directly to the transistor base when it is above a predetermined value. |
