| 摘要 |
PURPOSE:To adjust electric current of a large capacity electric-discharge lamp with simple constitution by providing impedance means and high frequency switching means between an electric-discharge lamp and commercial power source, and varying electric current flowing in the electric discharge lamp from turn off to turn on a light with impedance means by frequency of switching means. CONSTITUTION:Desired impedance means L1 and high frequency switching means S1 for an electric current adjusting of an electric-discharge lamp are arranged between an electric-discharge lamp 8 and input of a commercial power source. Means S1 is composed of a semiconductor switching element 4 connected to a pulse width variable oscillator 5, frequency of the oscillator 5 is varied, and ON/OFF of the element 4 is made a desired period. By ON/OFF of the element 4, the electric current flowing from a rectifier 3 to a high frequency coil or reactor 6 seriesly connected to the lamp 8 is controlled. And electric current flowing to the lamp 8 is varied from a turned off state to turned on state gradually, and lighting current of the electric-discharge lamp having large quantity can be adjusted with a simple operation. |
