| 摘要 |
PURPOSE:To confirm the operation of a Hall element while electricity is fed to a main circuit by applying a weak signal of specific frequency which is outputted by an oscillator to the Hall element, and then amplifying it and extracting only the signal of the specific frequency through a filter circuit. CONSTITUTION:The Hall element 1a of a current detector 1 inputs a DC current to be detected from the main circuit 11 and the weak signal of the specific frequency from the oscillator 7 and outputs a signal corresponding to their addition signal. This signal is amplified 2 and only the signal of the specific frequency is selected by the filter circuit 8 and outputted. Then a detecting circuit 9 compares the output with the output signal of the oscillator 7 to judge whether or not the operation state of the element 1 is normal. Further, the signal after the amplification 2 is outputted 5 according to the result of the comparison 3 with a reference voltage from a reference voltage generation part 4. Therefore, the operation of the element 1a is confirmed while a breaker 6 is fed with electricity. |
