PURPOSE: To eliminate a need to set a pulse transformer to a high impedance by taking out a constant current from a line input power and sending the discharging current of a charging/discharging circuit as a voltage through a switching element by the transformer.
CONSTITUTION: With respect to line voltages from lines L1 and L2, the power consumption is limited to a prescribed power by a constant current circuit. A capacitor 14 of a discharging circuit 14 is charged by the output of this circuit 8; and when the charging voltage reaches a prescribed value, a bi- directional switch 9 is turned on and the discharging current is supplied to a pulse transformer 10. The output voltage of the transformer 10 is inputted to a DC level converting circuit 30 and is processed by a first timer circuit 11 for prevention of the malfunction due to noise, an AND gate 13, a second timer circuit 12, and an integrating circuit 15, and the detection output of the DC level is generated at the time of connection of lines L1 and L2. These charging/discharging circuit and the switching element are used to eliminate a need to set the pulse transformer to a high impedance, and a connector checker is obtained which can use the transformer which has a high economic property and a small volume.
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NAKAWATARI YASUSHI
YOSHIDA MASARU
