| 摘要 |
<p>PROBLEM TO BE SOLVED: To detect the existence of vehicles in a park and the like by fixing 2 coils in the state of 0 mutual induction electromotive force and detecting the mutual induction electromotive force generated by the change in magnetic flux distribution. SOLUTION: Allotting a constant interval in a coil couple holder 3, a vertical and a horizontal coils 4 and 5 are fixed and each axis of 6 and 7 is set vertically and horizontally. These are buried immediately below ground surface 1 nearly horizontally. Both ends of coils 4 and 5 are connected to a processing circuit, respectively. High frequency alternating current of a few kHz is sent to one coil 4 and the existence of a vehicle is detected with the other coil 5 and the detection signal is sent to a control circuit. In this case, the electromotive force without a vehicle is suppress below 1 mV, and that with a vehicle, above 10 mV by the machining accuracy of the coil couple holder 3. By this, a stable and sure sensor can be obtained.</p> |
