| 摘要 |
PURPOSE:To facilitate the detection of an intermittent leak in a low voltage lead-in wire, in the display board of a leak display apparatus by succeeding display operation regardless of the presence of a leak on and after display operation accompanied by the detection of the leak. CONSTITUTION:When a leak current is flowed to a low voltage lead-in wire, said current is picked up by a current detection part 3 and the detection range of the leak current is set in a leak current setting circuit 12 through a clop circuit 11. Subsequently, the difference between the voltage inputted from the circuit 12 and reference voltage is amplified in a definite amplifying degree by an amplifying circuit 13 and, when the output voltage of the circuit 13 exceeds the preset reference voltage in a comparing circuit 14, a H-level signal is outputted to a relay circuit 15. The circuit 15 receives the H-level output signal to flow a pulse current to the coil of a display element 4 and a display board is reversed by 180 deg. to hold a reversal state by the residual magnetism of a magnetic pole rod to succeed the operation of leak current detection display. Therefore, display is certainly enabled not only in such a case that the leak is succeeded but also in such a case that the intermittent leak is generated and the detection of the lead-in wire, through which the leak current is flowed, becomes easy.
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