ORIGIN DETECTION DEVICE

摘要

[PROBLEMS] To provide an origin detection device capable of detecting an origin more accurately than in a conventional device by using magneto-resistive devices having fixed magnetic layers and free magnetic layers. [MEANS FOR SOLVING PROBLEMS] When the center (1c) of a magnet (1) is at the origin (P), a horizontal magnetic field component (H1) acts on the free magnetic layer of each magneto-resistive device to turn the free magnetic layer in the direction of the horizontal magnetic field. This stabilizes magnetization to make hysteresis sufficiently small to accurately detect the origin. When the center (1c) of the magnet (1) is positioned at the origin (P), no differential output is obtained otherwise, though differential output occurs and the origin can be detected by judging the existence of the differential output. This makes it possible to accurately detect the origin by a simple circuit not requiring a reference voltage setting circuit or the like.