| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent a detection distance wherein an object to be detected can be detected from changing. SOLUTION: In a detecting circuit including a cycle signal generation circuit 1 for generating cycle signals and a comparison circuit 3 which compares a change voltage Va changing in accordance with an amplitude change of the cycle signal subsequent to the detection of an object to be detected with a threshold value voltage Vth based on a reference voltage Vcc, thereby outputting a detection signal of the object to be detected, the comparison circuit 3 has a threshold value resistor R5 where a constant current runs so that a voltage at one terminal at the upstream side in a current direction becomes the reference voltage Vcc and a voltage at the other terminal becomes the threshold value voltage Vth.</p> |
