| 摘要 |
PROBLEM TO BE SOLVED: To provide a proximity sensor, wherein increase in the size, the manufactures cost and the management cost can be avoided and mutual interference can be prevented while suppressing a sensing response speed from being deteriorated. SOLUTION: A parallel connection circuit of a sensing coil 12 and a capacitor 13 is connected in parallel with an amplifier circuit 14 in an oscillation circuit 11 and a sub capacitor 15 is connected in parallel with the capacitor 13 via a switch 16. The switch 16 receives a control signal S from an external controller 30 and is operated to be open when the control signal S is at a high level and closed when the control signal S is at a low level. The oscillation circuit 11 oscillates a frequency different between a 'standby state' and an 'operating state' by the switching operation of the switch 16 while continuing the oscillation.
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