| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent demagnetization with an electric current passing through an electric wire to be measured. SOLUTION: As output of a comparator 102 is H, when a reference voltage VTH is larger than a voltage effective value Vrms when a demagnetizing switch 309 is turned on (a switching signal H), output of an AND circuit 103 becomes H for driving a demagnetizing circuit 308. When the reference voltage VTH is equal to a voltage effective value Vrms or smaller, a comparison logic signal of the comparator 102 is L, the demagnetizing circuit 308 win not be driven, and an error display is displayed on a display part 106.</p> |
