| 摘要 |
A continuity monitor and indicator circuit for monitoring the continuity of a segment of a pair of control conductors along which a control current flows includes capacitors at each end of the segment being monitored, which capacitors are connected to bridge the conductors and provide an a.c. electrical path between the conductors. A transformer has its secondary winding connected in series with one of the control conductors in the segment and an oscillator is connected to the primary winding of the transformer. The oscillator arrangement is such that it will provide an output signal when the closed a.c. electrical loop formed by the secondary winding of the transformer, the control conductor segment, and the bridging capacitors is broken. A detector is responsive to the oscillator output to detect such output and supply a detector output to a delay means which, in turn, provides an alarm output after receipt of the detector output for a predetermined period of time. An indicator means, including a bidirectional magnetic latch, provides an alarm indication in response to the alarm output from the delay means.
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