PULSE SIGNAL GENERATING METHOD AND DEVICE THEREFOR

摘要

PROBLEM TO BE SOLVED: To surely generate a pulse signal by changing a magnetic field according to the behavior of an object to be detected for a permanent magnet, and detecting change generated in a magnetic element which is likely to cause large Barkhausen jump for generating a pulse. SOLUTION: This device is provided with a detecting coil 20 wound around a magnetic element 10 which is likely to cause large Barkhousen jump and a bias magnet 30 in the neighborhood of the magnetic element 10. An auxiliary magnet 50 and a magnet 40 for change are provided as permanent magnets shaped like thin boards. When a magnetic body being an object 60 to be detected approaches the changeable magnet 40, a magnetic field between the magnet 40 for change and the auxiliary magnet 50 is strengthened, and made superior to a magnetic field generated by the bias magnet 30. The magnetic field in the same direction as the hard layer of the magnetic element 10 is added, and a soft layer is inverted in the same direction as that of a hard layer so that large Barkhuausen jump can be generated. Thus, a pulse voltage can be generated in the detecting coil 20 by an electromagnetic inducing action.