| 摘要 |
It is an object of this invention to provide a fence sensor which can achieve an excellent detection stability without using a current for generating an electric field nor infrared rays. The fence sensor comprises a detection electrode (8); a reference electrode (9) insulated from the detection electrode (8); a chargeable member (4) insulated from both of the detection electrode (8) and the reference electrode (9); and a detection circuit (20) for detecting a change in the electrostatic capacitance between the detection electrode and the reference electrode that is generated by the presence of an object to be detected within a detection region of the detection electrode. In this fence sensor, the chargeable member is arranged such that at least a part of the chargeable member is situated within the detection region of the detection electrode. Further, the chargeable member is formed from a conductor.
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