| 摘要 |
PROBLEM TO BE SOLVED: To provide a proximity switch in which the field strength detection level of a radio wave detection circuit can be set as close as possible to a field strength limit level functioning as a proximity switch while taking account of variation in the characteristics of the proximity switch as small as possible. SOLUTION: In the proximity switch, variation of output from an oscillation circuit section incident to proximity of an object is compared at a comparison circuit section and when a specified amount of variation is detected, an object detection signal is outputted from a basic circuit comprising a semiconductor integrated circuit and a passive component. A radio wave detection circuit comprising a radio wave detection element operating to detect radio wave in the circuit by disabling output of the object detection signal from the basic circuit when a radio wave of a specified strength is detected externally is incorporated in the semiconductor integrated circuit. The radio wave detection circuit is a proximity switch having radio wave resistant characteristics lower by a specified value as compared with an element having lowest radio wave resistant characteristics in the basic circuit.
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