| 摘要 |
PROBLEM TO BE SOLVED: To immediately detect that a commercial AC power supply is not connected. SOLUTION: A capacitor 24 is connected to both ends of an electrical outlet 10 which is connected to or disconnected from the commercial AC power supply. The both ends of the capacitor 24 are connected between input terminals 8IN-1, 8IN-2 of a DC power supply circuit 8. A light emitting diode 16L of a photocoupler 16 is connected between the both ends of the capacitor 24 via a high pass filter 21. When the electrical outlet 10 is disconnected from the commercial AC power source, the high pass filter 21 rapidly intercepts a current discharged from the capacitor 24, and rapidly stops the light emitting diode 16L emitting light. COPYRIGHT: (C)2008,JPO&INPIT
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