| 摘要 |
PURPOSE:To simplify the construction works by securing sufficient dimming range of a dimmer for high voltage discharge lamp by selectively inserting a reactor for dimming under current control into a power circuit. CONSTITUTION:Ballast stabilizers 12a, 12b are connected in parallel with a power supply 13 in a plurality of high voltage discharge lamps 11a, 11b.. A reactor 18 is inserted in series with a power supply 13 line through a main switch 14 with a dimmer switch 19 provided to short the input and output sides of the reactor 18. The switch 19 is controlled by a control circuit 21 for receiving the signal from a dimmer signal source 20. The switch 19 is opened when receiving a diammer command from the source 20 to thereby insert the reactor 18 into a power circuit so as to control the current. The switch 19 is closed when receiving no dimmer command to shorten the reactor 18 to thereby release the restriction of the output current amount. |
