| 摘要 |
PROBLEM TO BE SOLVED: To construct an oscillation failurep detection circuit at a low cost when the oscillation circuit of a protective relay or monitoring control equipment is stopped. SOLUTION: The oscillation failure detection circuit includes: a differentiating circuit for detecting the change of clock signals in order for the oscillation circuit to detect the stop of the supply of a clock; a diode for limiting signals from the differentiating circuit to rise; a pulse shaping circuit for shaping output signals; an inverter circuit; a charging/discharging circuit; and a level detection circuit for comparing the output voltage level of the charging/discharging circuit with a predetermined reference value and outputting signals when it exceeds the reference value. COPYRIGHT: (C)2011,JPO&INPIT
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