| 摘要 |
PURPOSE:To eliminate the wasteful internal loss at the time of low voltage and high voltage by connecting two capacitors in series between power supply application terminals and connecting secondary coils and discharge lamps in series on both ends of one capacitor when the power supply application voltage is high. CONSTITUTION:When the power supply voltage is low, primary coils 20a, 20b are connected in parallel, and a power supply application terminal 14 is connected to the serial circuit of secondary coils 21a, 21b via a capacitor 25. When the power supply application voltage is high, the secondary coils 21a, 21b are connected in series, two capacitors 26, 27 are connected in series between power supply application terminals 13, 14, and the middle point is connected to the serial circuit of the secondary coils 21a, 21b. If the capacities of the capacitors 25-27 are set to the predetermined values, voltage shares of the coils 20a-21b at the time of no load (when discharge lamps 15, 16 are turned off) and when they are lit are made equal. The current flowing through the secondary coils 21a, 21b is constant and same at the time of high voltage and low voltage. The current flowing through the primary coils 20a, 20b is also same. |
