| 摘要 |
In a proximity sensor, in order that it is not affected by a cable length and an environment of a setting place or the like, and that it is extremely stable in operation, and that it can be used nearing in a maintenance-free state, there are included a detecting electrode arranged in an object detecting area and made of a metal plate formed like a plate; a charge system with a direct current power source; a discharge system with a current detecting unit; and a switch for alternately switching the charge system and the discharge system to the detecting electrode by a specified switching frequency, and an electrostatic capacity between a detected object and the detecting electrode is detected as current flowing in the discharge system.
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