摘要 |
<p>A probe (10) has a coil (23) for inductive transmission of signals from a source when the probe is in proximity to a receiver. A switch (41) connects the coil (23) to the source in response to a position sensor (21, 22) of the position of a plunger (16) relative to the body of the probe, the position being changed by relative approach to the receiver. The sensor may be magnetic and the sensor and switch may be combined in a Hall Effect device.</p> |