| 摘要 |
PURPOSE:To enable opening/closing of an AC power supply line to be made with a small relay and a simple drive circuit by delaying the front or rear edge of a rectangular wave generated by turning on/off of an operation switch from an AC voltage wave form faired a prescribed time. CONSTITUTION:An AC voltage (wave form a) of an AC power source 10 is consistently detected with a frequency detector 2, is inputted into a 0V timing circuit 4 with faired to a rectangular wave in a wave form fairing circuit 3, and is outputted according to operation of an operation switch 1 as a signal applied timing as of 0V of the AC voltage. When the switch 1 is on, a preset value in a relay on timing circuit 6 is a value delaying the front edge of a waveform d to that of a wave form e so that a contact is made to on at a 0 cross point of the waveform a considering a response time of the relay 9. And when the switch 1 is set to off, the 0 cross point is attained when the relay contact is off by presetting a relay off timing circuit 7 considering a reset time of the relay 9. This enables equipment to be miniaturized, and timing of operation to be simply adjusted with a digital switch.
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