COMMON MODE CHOKE COIL AND ITS IMPEDANCE ADJUSTING METHOD

PROBLEM TO BE SOLVED: To provide a common mode choke coil and its impedance adjusting method wherein a necessary inductance value is obtained, while a necessary characteristic impedance can be obtained. SOLUTION: In the common mode choke coil 31, a winding 36 is densely wound on the outer periphery of the cylindrical trunk 33 of a bobbin 32 as a single layer. A winding 37 is densely wound doubly on the winding 36 as a single layer. A winding 46 is densely wound on the outer periphery of the cylindrical trunk 43 of a bobbin 42 as a single layer. A winding 47 is densely wound doubly on the winding 46 as a single layer. The windings 36, 37, 46, 47 are wound so as to strengthen a magnetic flux mutually when the noise current of a same phase flows. In the windings 36, 37, and the windings 46, 47, at least one of their conductive diameters, the thickness of an insulating film and the relative dielectric constant of the insulating film is adjusted, whereby impedances are adjusted between the windings 36 and 37, and between the windings 46 and 47. An insulating sheet may intervene between the windings 36 and 37, and between the windings 46 and 47. COPYRIGHT: (C)2006,JPO&NCIPI