| 摘要 |
953,004. Control systems for high pressure discharge lamps. PATENT-TREUHAND-GES. FUR ELECTRISCHE GLUHLAMPEN. Jan. 17, 1961 [Jan. 18,1960], No. 1885/61. Heading H2H. [Also in Division G3] The current flowing in a high pressure discharge lamp 1 is maintained constant at a desired value by comparing two voltages one from a device 10, representing the desired lamp current and the other, from a device 9, and derived from a resistor 3 in the lamp circuit, which is representative of the actual lamp current, the difference between these two voltages being used to control the duration of the impulses produced by a multivibrator 8 which in turn controls the mark-space ratio of a transistor 4 in the lamp circuit. The multivibrator 8 is normally controlled at the line frequency of the A.C. supply by a phase shifting device 7. Alternatively, the phase shifting device may be used to control the power rectifier 5 which may comprise silicon controlled rectifiers whilst the multivibrator may be of the self-oscillatory type. When light emission from the lamp is not required the lamp is supplied with a current of low value over a second transistor 11 in order to keep the lamp ready for instant operation. A high-frequency starting device 15 is provided which is utilized by way of a switch 2, this switch also being used to connect the lamp to the output of the rectifier 5 over a resistor 16 and an inductor 17. |
