| 摘要 |
<p>PURPOSE:To control the electric resistance between electrodes so as to be changeable, by applying or eliminating pressure to or from the electrode of the open end side of a spool, with a plunger constituted of a cylindrical permanent magnet which is restored and energized by a helix spring in a hollow part on the center axis of the spool around which a coil is wound. CONSTITUTION:A spool 2 has a hollow part 10 on the center axis, and one end thereof is sealed; a coil 1 is wound around the outside of a trunk, and both ends of the coil are connected with coil terminals 3 penetrating the spool 2. Into the hollow part 10, the following are inserted; a plunger 4 constituted of a cylindrical permanent magnet wherein a disk type conducting rubber 5 is fixed on one end, and an electrically insulated helix spring 6 whose diameter is larger than the plunger 4 and the conducting rubber 5. When a voltage is not applied between the coil terminals 3, the plunger 4 is made to stand still by the energizing force of the spring 6. When a voltage is applied to the coil 1 in the repulsive direction of magnetic field of the plunger 4, it moves in the direction of thin plate electrodes 7. Thereby said electrodes 7 are pressed, and the electric resistance between the electrodes is changed.</p> |
