| 摘要 |
A circuit 16, (76) (119), (Figs, 3 to 7), responsive to voltage across a ballast reactor 14 or to current through the lamp 10, causes a first switch 18 to be opened to deactivate a pulse generator 12 in response to starting of lamp 10. Pulse generator 12 produces high voltage pulses suitable for starting and hot restarting of the lamp. If the lamp does not start within a predetermined interval a second switch 20, (115) (Figs. 6,7), is latched open to inhibit pulse generator 12. The second switch may be opened in response to closure of a thermally operated switch (135), (Figs. 6,7), heated by a resistor (140) associated with the starting pulse generator. In alternative arrangements, Fig. 1 (Figs. 2 to 5), timing circuits 22,28 cause the second switch 20 to be repeatedly opened and closed to establish alternating active and inactive periods for generator 12 (eg. 0.67 secs and 1.5 secs), until timer 28 causes switch 20 to be latched open in response to heating of a NTC resistor 26, or a switch, by a resistor 25. <IMAGE> |
