PURPOSE: To reduce the amount of leakage of magnetic flux and the noise of electromagnetic wave caused by the above-mentioned magnetic flux leakage by a method wherein a flat-shaped coil is interposed between a pair of opposingly arranged magnetic materials in an electrically insulated manner, and a spacer is placed between the flat-shaped coil and at least one of the pair of magnetic materials in such a manner that the spacer goes in and out freely.
CONSTITUTION: In a variable inductance element 11, both surfaces of a plane- surfaced coil 12, which is formed by spirally winding a conductor 12a, are pinched by a pair of elastic magnetic plates 14a and 14b through the intermediary of a pair of sheet-like electric insulators 13a and 13b. A spacer 15 is interposed retractively between the magnetic plate 14a and the electric insulator 13a. As the magnetic flux density of the magnetic plate 14a increases or decreases according to the amount of motion of the tip of the spacer 15 required to reach the full insertion end O, the inductance value of the variable inductance element 11 can be changed suitably. Also, the amount of leakage of magnetic flux leaking outside can be reduced, and the electromagnetic wave noise caused by the above-mentioned leakage of magnetic flux can also be reduced.
EZAKI SHIRO
KIMURA MITSUTOSHI
ISHIZUKA AKIO
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