| 摘要 |
1,174,897. Supply systems for road vehicles. JOSEPH LUCAS (INDUSTRIES) Ltd. 8 March, 1967 [25 March, 1966], No. 13261/66. Heading H2H. [Also in Division G3] A battery-charging system for a road vehicle is provided with a warning lamp 20 controlled by a transistor 19 responsive, via circuit members 17, 18, 22, 23, to the output of the vehicle generator, the arrangement being such that the lamp is extinguished when the generator is producing an output and the lamp is illuminated when the generator is not producing an output. With no output, closure of a switch 16 (e.g. the ignition switch of the vehicle) charges a capacitor 18 to make transistor 19 conductive and so illuminate the lamp. A terminal 23 is connected so as to be responsive to the generator output which, when present, causes the potential of terminal 23 to vary between positive and negative battery potential, this action in turn causing the capacitor 18 to discharge and charge. However the time constants of the circuit are so chosen that capacitor 18 cannot charge sufficiently to make the transistor 19 conductive and hence the lamp 20 is extinguished when the generator is producing an output. The generator may be an alternator/ rectifier unit or a D.C. generator. In the former case, the terminal 23 is connected to a phase point or to the star point of the alternator. Other connections are possible, providing that the potential at the junction of members 17, 18 is never allowed to become sufficiently positive to turn on the transistor 19. For example the terminal could be connected to the field winding of the generator. In a modification, Fig. 2 (not shown), the circuit comprising members 19, 20, 21 is connected directly across the terminals 13, 14, members 17, 18, 22 are omitted and the transistor 19 is controlled by a circuit comprising a second transistor and two resistors. In this modification there is no time delay effect. |
