| 摘要 |
An improved control circuit for an electric discharge lamp includes a temperature-dependent capacitor connected in series or in parallel with the discharge lamp. The capacitor preferably has a negative temperature characteristic and is responsive to the heat generated in the discharge lamp. During the start-up period, the lamp temperature is low and the capacitance is relatively high, whereas in the operating condition of the lamp its temperature increases and the capacitance of the capacitor drops to a relatively low value. In the series arrangement, the starting current of the lamp is thereby increased over the operating current to promote better ignition of the lamp. Similarly, in the parallel arrangement the high capacitance capacitor facilitates lamp ignition, whereas during normal lamp operation the low capacitance shunt branch effectively appears as an open circuit exerting minimal influence on the lamp operation. |
