| 摘要 |
PURPOSE:To make a power source transformer unnecessary by providing an intermediate tap on a choke coil, and connecting a series resonance winding formed on one side of the intermediate tap and a capacitor for power-factor improvement to a power source in series. CONSTITUTION:When no load is imposed, a current flows to the series resonance winding 13 of a choke coil 14 and a capacitor 17 for power-factor improvement, and a series resonant voltage is induced in the series resonance winding 13 by the inductance of the series resonance winding 13 and the capacitance of the capacitor 17 for power-factor improvement. The series resonant voltage is generated on the side to add to the power source voltage, and since a main winding 12 is provided at the opposite side to the series resonance winding 13 placing the intermediate tap 15 at the center, the inducted voltage on the main winding 12 induced in the same direction as the series resonant voltage is generated on the side to reduce the voltage of a commercial AC power source 11. And the nonload secondary voltage between a discharge lamp 16 is reduced to the voltage lower than the voltage of the commercial AC power source 11, and the voltage can be set as desired by the winding number ratio of the main winding 12 and the series resonance winding 13. Consequently, no power source transformer is required. |
