| 摘要 |
<p>A proximity detector comprises a pair of antennae being disposed along the front edge of a door and at a space therebetween, a pair of coils constituting series resonance circuits, together with each electrostatic capacities of the antennae which are connected in series with the coils, an AC power source for supplying voltages to the series resonance circuits; rectifying circuits for rectifying the voltages produced on the antennae by the AC power source, and a differential amplifier circuit for amplifying difference between the outputs of the rectifying circuits, the output of the differential amplifier controlling the movement of the door.</p> |
