| 摘要 |
PURPOSE:To reduce the number of checking processes for a clock and to prevent a mistake in checking, by outputting a passing signal when a current value detected in a current detecting element in within a prescribed range, and by outputting a rejection signal when said value is outside the prescribed range. CONSTITUTION:A digital display watch 5 is connected to a current checking apparatus 10. When an operation input circuit 12 is operated, a start signal is supplied to a control circuit 13. Thereby an output circuit 14 supplies a voltage V2 to the watch 5 after a prescribed delay time passes, while the control circuit 13 supplies a clock signal to a comparator circuit 17 simultaneously. Here the watch 5 works on a lighting mode with a clock phi1 and on a clock mode with a clock phi2. At the falling points of clocks phi3 and phi4 a current detecting circuit 18 conducts the determination of current values of a clock terminal 6, a display terminal 7 and a lighting terminal 8 in the clock mode and the lighting mode.
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