| 摘要 |
PURPOSE:To suppress a rush current which flows on a load device, by delaying the energizing of a triac by decreasing the resistance value of a current- resistance conversion means corresponding to the rush current and increasing the cycle of a trigger pulse being generated by the energizing of a trigger diode. CONSTITUTION:The rush current, after being detected by a current detector 4a and full-wave rectification being applied on it, is added on the LED of a photocoupler 4c. The LED of the photocoupler 4c is lit at illuminance propor tional to a voltage applied on it, and the resistance value of a Cds which receives a beam of light emitted by the LED changes inversely proportional to the illuminance of the LED. In other words, when a large amount of rush current is detected by the current detector 4a, the resistance value of the Cds is decreased, and the cycle of the trigger pulse being generated by the energizing of a trigger diode 4d is increased, then, the energizing of a small triac 4e is delayed. In such a way, the phase control of a large triac 3 is performed by the energizing of the small triac 4e, and the rush current to the load device 2 can be suppressed.
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