MAGNETIC FIELD DETECTION APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a sensitive magnetic field detection apparatus for detecting timing when an external magnetic field exceeds a specific level. SOLUTION: A pulse current is supplied to a magneto-sensing element 10 for indicating magnetic impedance effect where impedance that is a constituent in the direction of a detection axis changes for excitation in an orbital direction. The induced voltage of a detection coil 20 that is wound in an orbital direction of the magneto-sensing element 10 is detected by an electronic switch 401 that is turned on in synchronization with a pulse current, and a detection means 40 for retaining a voltage corresponding to the peak. The output of the detection means 40 is compared with a specific level by a comparator 501.