Patent ID: 7208939
Filing Date: 2007-04-24
Classification: G01D

Abstract:
1. A sensor adapted to sense the angular position of a rotatable shaft, the sensor comprising: a bipolar annular magnet connected for rotation coaxial with the shaft; the annular magnet having poles located 180 degrees apart, wherein said magnet is magnetized by inserting an iron core through its inside diameter during magnetization thereof to obtain enhanced linearity of magnetic flux density as the magnet rotates about its center axis through approximately +/−60 degrees from a neutral position equi-distance between the poles; a first stationary magnetic field sensor element and a second stationary magnetic field sensor element spaced from said first sensor element positioned to sense the change in magnetic flux as the magnet rotates and adapted to provide output signals proportional to the magnetic flux sensed; and an amplifier circuit to provide a differential output voltage that varies linearly with shaft rotation of approximately +/−60 degrees from said neutral position and having a magnitude proportional to the angular position of the shaft.