| 摘要 |
PROBLEM TO BE SOLVED: To favorably eliminate an influence of an external induction noise to allow measurement and drive, even in making measurement, connecting a measuring instrument to an output end via a long cable, in a differential amplification type magnetic field detecting circuit using two magnetic impedance effect elements. SOLUTION: This magnetic field detecting circuit is provided with a negative feedback circuit 5 for negative-feeding back an output from a differential amplification circuit 4 to the first magnetic impedance effect element 1a and the second magnetic impedance effect element 1b, via the first negative feedback magnetic field coil 5a and the second negative feedback magnetic field coil 5b. An off-set means 40 is provided in the differential amplification circuit 4 to make an output voltage from the differential amplification circuit 4 when both terminal input voltages v<SB>1</SB>, v<SB>2</SB>satisfy v<SB>1</SB>=v<SB>2</SB>brought into a prescribed voltage V<SB>0</SB>, and a bias voltage impression circuit 50 is provided in the negative feedback circuit 5 to negate the voltage V<SB>0</SB>. COPYRIGHT: (C)2006,JPO&NCIPI
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