Apparatus for measuring the magnetic field and / or the magnet field changes in an air gap

摘要

To provide a pulsed output signal with a frequency indicative of rotational speed of a toothed wheel 2 spaced from a fixed magnet 1, there is provided on the face 6 of the magnet a field responsive semiconductor chip 3 comprising an integrated circuit with two Hall generators 9, 10 arranged one after the other in the direction of rotation and associated electrical energy supply, measuring, and evaluation circuits, including a differential amplifier with hysteresis for receiving the Hall signals in order to reduce spurious signal due to vibration. The distance between the two Hall generators (9, 10) should equal or be less than one tooth width B. The electric energy supply and the measured signals are conducted via one sole double line. IMAGE