PURPOSE: To prevent the generation of noises without filling adhesives and without lowering performance by increasing the number of turns of a primary coil and a space between gap sections on the assumption that specific conditions are satisfied and reducing the areas of the gap sections and magnetic flux density passing through the gap sections.

CONSTITUTION: Formulae 1, 2 are satisfied in order to keep the electrical characteristics of a stabilizer constant. Where l2 is the space between the gap sections, N1 the number of turns of the primary coil, Sg the areas (m2) of the gap sections and B magnetic flux density (Wb/m2) passing through the gap sections in formulae 1, 2. It is necessary to reduce the areas of the gap sections or reduce magnetic flux density passing through the gap sections in order to cut down the attracting force of the gap sections. Accordingly, the number of turns N1 of the primary coil is increased while the space l2 between the gap sections is increased.