| 摘要 |
PURPOSE:To surely preheat a filament to apply start voltage and to prolong the life of a discharge lamp by performing a reset wherein the capacitor of a soft starting timer circuit, performing the preheating of the filament of the discharge lamp, is surely discharged when a power source is turned on. CONSTITUTION:The terminal voltage of a capacitor C1 is increased at the time of the oscillation start of an inverter 5, and is supplied to the base of the transistor Q5 of a reset circuit 10. When the transistor Q5 is turned on (continued) to earth the capacitor C2 of a timer circuit 8 and if there is an residual electric charge, a reset is performed to discharge the residual electric charge. Starting the oscillation action of the inverter 5 causes the terminal voltage of the capacitor C1 becomes 0V concurrently to turn the transistor Q5 of a reset circuit Q7 off. Preheating the filament of a discharge lamp 7 is surely performed by the reset for discharging the residual electric charge of the capacitor C2 of the timer circuit 8 due to the a short break of an A.C. power source 2 and the like, and then high start voltage is applied. |
