MINIATURE CROSSED-COIL GAUGE HAVING AN ACTIVE FLUX RING

摘要

A miniature crossed coil gauge (30) having an oriented rare earth magnet (40) fixedly mounted on a rotary shaft (38) supplying a magnetic flux directed transverse to the shaft axis. The gauge housing provided by upper (32) and lower (34) bobbins surrounds the magnet and supports the shaft. First (42) and second (44) coils are wound about the gauge housing in a crossed coil orientation encircling the magnet. A flux ring (50) is disposed around the first (42) and second (44) coils axially aligned with respect to the magnet (40). The magnet (40) has sufficient strength and the flux ring (50) is mounted in sufficiently close to the first and second coils to redistribute flux supplied by the magnet so that magnetic flux measured at the surface of the coils is substantially increased relative to the magnetic flux density measured with the flux ring removed. This gauge construction facilitates fabrication of gauges so small that they can be directly mounted on printed circuit boards using conventional electronic component mounting equipment.