| 摘要 |
PURPOSE:To omit a forcible cooling operation done by a cooling body, etc. by superposing the trigger voltage onto the AC power supply voltage to short- circuit a control rectifying device based on the superposed voltage and reducing the heat dissipation of this rectifying element. CONSTITUTION:The superposition voltage of the trigger voltage and the AC power supply voltage is produced between terminals X and Y after a fixed period of time decided by a time constant circuit consisting of a resistance R5 and a capacitor C3. The superposition voltage is rectified by a diode D3 and charges a capacitor C5. This charged voltage is impressed to a relay G and contacts V and W are closed. Then a triac K serving as a control rectifying device is short-circuited. Thus the triac K conducts just for a short period of time decided by the time constant of the time constant circuit and therefore produces no heat actually. This omits a forcible cooling operation done by a cooling body, a blower, etc.
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