| 摘要 |
<p>An electromagnet (13) has yoke (19) moved away from core (17). The yoke closes magnetic circuit of the electromagnet. An electrical or electronic switching device such as Hall sensor (25) responds to magnetic field of the magnetic circuit. The switching device taps the core or yoke at two sites (31,33) which are spaced apart from one another along lengthwise direction of magnetic flux. A reed switch (23) is located in the core or yoke along lengthwise direction of magnetic circuit.</p> |
