| 摘要 |
PURPOSE:To execute a detection without necessitating a special power source, and to easily adjust a current by displaying whether an electric conductive body is conducted electrically or not, and whether the current of a prescribed value is conducted or not, by the lighting of a lamp. CONSTITUTION:A lamp LD1 is lighted almost simultaneously when the current is conducted to the electric conductive body 1, and it is known that the current is conducted to the electric conductive body 1. Also, a smoothed input voltage is increased approximately in proportion to a voltage between both terminals 3, 4 of a CT coil 2 and led into the input terminal of a comparator IC1-1. On the other hand, a smoothed reference voltage VB is increased approximately in proportion to the voltage between both terminals 3, 4 at the time point when the voltage between both terminals 3, 4 of the CT coil is low, led into the reference terminal of the comparator IC1-1, and when said voltage reaches a Zener voltage, the voltage is not increased further. When the voltage between both terminals 3, 4 of the CT coil goes to a prescribed value, a voltage is generated between the output terminal of the comparator and a terminal 9, and a second lamp LD2 is lighted.
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