| 摘要 |
<p>PURPOSE:To shorten the delay of the detection of power failure by mounting a rectifier rectifying the AC passed through a filter circuit, a photocoupler for detecting power failure driven by the supply of a current after rectification and the condenser interposed between the filter circuit and the rectifier. CONSTITUTION:A photocoupler 24 for detecting power failure is connected to a rectifier 23 subjecting the AC passed through a filter circuit 21 to full-wave rectification and a condenser C5 is provided between the filter circuit 21 and the rectifier 23. When power failure is generated, the charge accumulated in the respective condensers C1 - C4 of the filter circuit 21 is gradually discharged by a resistor R1, whereas said charge is supplied to the condenser C5 as a DC component. As a result, the current flowing through a resistor R2 is rapidly reduced and the photocoupler 24 is turned OFF. That is, the condenser C5 suppresses the adverse effect on the detection of power failure due to the charge accumulated in the respective condensers C1 - C4 of the filter circuit 21 at the time of the generation of power failure.</p> |
