| 摘要 |
PURPOSE:To apply the same electric power as an output in a normal condition to a load, and maintain a predetermined dimming level by adjusting a pulse number of basic pulses for on-controlling in case the output of an AC power source has fluctuation. CONSTITUTION:A power source on/off means 2 for putting on/off an output of an AC power source 1 and giving it to a load 5, and a basic pulse forming means 3 for forming basic pulses by decomposing a half cycle of the output of the AC power source into (n) parts are provided, an output of the power source on/off means 2 is fed back, and it is detected how many pulse number is increased or decreased compared to one in a normal condition in a condition to which this output corresponds. On-control is performed at a timing with an increase or decrease of the number of basic pulses equivalent to a detected increased or decreased pulse number for controlling supply of the AC power source output to the load 5. A dimming level can thus be maintained to a fluctuation of an output voltage of the AC power source 1, thereby lighting can be performed at a set dimming level constantly.
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