Proximity sensor using magneto-resistive elements and permanent magnet

摘要

A proximity sensor comprises two magneto-resistive elements (31, 32) disposed in a common plane and displaced from a permanent magnet (40) lateral surface. The sensing plane is generally parallel to the north-south axis (42) of the magnet. A detection zone (90) is defined w.r.t. a preselected pole face (49) of the magnet. The magneto-resistive elements output first and second signals, compared in a Wheatstone Bridge to define a third signal. The latter indicates the presence or absence of a magnetically-permeable object (82) within the detection zone. The magneto-resistive elements may each comprise plural magneto-resistors, arranged in laminar association with each other.