Magnetic sensor having excitation coil including thin-film linear conductor sections formed on bobbin with detection coil wound thereon

Abstract

A magnetic sensor includes a bobbin having one surface provided with a toroidal groove, and a toroidal inductor accommodated in the groove. The toroidal inductor has a toroidal core and an excitation coil wound on the toroidal core. The excitation coil has a conductive pattern of a plurality of thin-film linear conductors individually extending in a radial direction on a surface of the bobbin and on inner side and bottom surfaces of the toroidal groove with a predetermined angular space, a toroidal core received in the groove, and a plurality of connecting wires each of which is bridged over the toroidal groove and toroidal core to interconnect an inner end of one of the thin-film linear conductors and an outer end of a next adjacent one of the thin-film linear conductors. The conductive pattern and the connecting wires form the excitation coil wound around the toroidal core. Thus, the toroidal inductor is formed in the toroidal groove. The connecting wire may be formed as a conductor pattern on a printed circuit board. In another embodiment, the toroidal inductor may be formed on a printed circuit board, and the toroidal inductor is accommodated in the groove of the bobbin without the conductive pattern by coupling the printed circuit board onto the bobbin.