| 摘要 |
PROBLEM TO BE SOLVED: To lengthen the length of an area whose magnetic field is detectable by a sensor, maintaining the length of a base line short. SOLUTION: This sensor is equipped with a core 1 in the shape of a racetrack, an exciting coil 2 wound on the core 1 toroidally, a differential magnetic field detecting coil 3 composed of differential windings 3a, 3b, 3c, 3d wound in reverse directions alternately with a pitch of L on the core 1, a common magnetic field detecting coil 4 wound in one direction with uniform distribution on the core 1, a first feedback circuit 5 which applies a negative feedback of a feedback signal D to a differential magnetic field detection signal B obtained from the detecting coil 3, and a second feedback circuit 6 which applies a negative feedback of a feedback signal F to a common magnetic field detection signal E obtained from the detecting coil 4. A base line length becomes equal to the pitch L, and the length of an area capable of detecting a magnetic field becomes [(2×N-1)×L]. Namely, the length of the area whose magnetic field is detectable can be lengthened to [2×N-1] times, three times even in the minimum case, as much as the base line length. COPYRIGHT: (C)2007,JPO&INPIT
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