Abstract: A noncontact type rotation sensor, which can detect the rotational movement of a gear with high sensitivity and precision without causing any erroneous output, is disclosed. To a magnetic gear is applied a bias magnetic field by a bias magnet from the direction of the teeth of the gear. A sensor part disposed within the bias magnetic field comprises a substrate and a plurality of magneto-resistive elements mounted on the substrate in parallel to the teeth of the gear and electrically connected in series one after another. The sensor part detects the magnetic vector of the bias magnetic field varying according to the rotation of the gear as the composite value of the variations of the resistance values of the plurality of magneto-resistive elements connected in series one after another.

Abstract: According to this invention, a device for detecting magnetism comprises; a substrate, an interposed insulating layer containing impurities therein, formed on the substrate, and a ferromagnetic magnetoresistive element formed on the interposed layer, wherein at least a portion of the interposed layer on which the ferromagnetic magnetoresistive element is formed has a concentration of impurities of less than a predetermined value. Further, in the device of this invention, the surface of the layer interposed between the substrate and the ferromagnetic magnetoresistive element has a surface roughness of less than 120 and an angle between a contacting surface of a conductive wiring and the ferromagnetic magnetoresistive element and the surface of the interposed layer is less than 78 degrees.

Abstract: A current detecting device comprises a substrate, a magnetism sensing member made of ferromagnetic magnetoresistance element, an insulating member, and a conducting member, and these members are formed by a photolithography technique such that the magnetism sensing member is electrically isolated from the conducting member by the insulating member. When a current flows into the conducting member, the magnetism sensing member responds to a magnetic field generated by the current. At this time, the resistance of the magnetism sensing member changes due to a magnetoresistance effect in accordance with the intensity of the current. Therefore, the current can be measured by detecting the resistance change. In such a current detecting device, there is no reactance component thereby achieving high sensitivity when detecting the current.

Abstract: A potentiometer includes a magnetoresistive element made of ferromagnetic material. A device applies a magnetic field to the magnetoresistive element. An absolute value of the magnetic field applied to the magnetoresistive element is equal to or greater than a saturation magnetic field with respect to the ferromagnetic magnetoresistive element. The magnetic field applying device is movable relative to the magnetoresistive element.