METHOD FOR DETECTING ELECTRICAL SIGNAL ACCOMPANYING MAGNETIC FIELD CHANGE DUE MAGNETIC SUBSTANCE AND DETECTING DEVICE USED THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a detecting method for detecting an electric signal accompanying magnetic field change due to a magnetic substance in a simple circuit configuration, and to provide a detecting device used for the detecting method. SOLUTION: The detecting device 20 for evaluating the magnetic substance includes a magnetic field generating device 22. The magnetic field generating device 22 includes a Helmholtz coil composed of two exciting coils 22a and 22b, and generates a uniform alternating magnetic field by a drive device 24. Two sensors 26a and 26b are arranged in the uniform alternating magnetic field. A magnetism sensitive detected body 30 is put at the side of one sensor 26a, and the magnetic field change accompanying change of a magnetic state is output from the sensors 26a and 26b. The electric signals due to the uniform alternating magnetic field are canceled by detecting the difference between outputs of the electric signals and the electric signals corresponding to the magnetic field change due to the change of the magnetic state of the magnetism sensitive detected body 20 are detected. COPYRIGHT: (C)2006,JPO&NCIPI