Compact magnetic counter for monitoring displacement or revolutions

摘要

The monitor uses changes in magneto-resistance to measure displacement or revolutions and consists of a magneto-resistance element (18) positioned over a pre-magnetising magnet (25a). The pre-magnetiser is situated close to the object to be measured (11), for example a cog wheel, at right angle to its direction of turn and produces a magnetic field in it. The magnets resistance element is joined to the pre-magnetiser at its pole face closest to the moving object on the same plane. This produces a change in resistance value following a change in magnetic field in reaction to the movement of the object. It consists of magnetic resistance microelements switched in series lengthwise, (18b) at right angles to other microelements (18a).