| 摘要 |
PROBLEM TO BE SOLVED: To provide a proximity sensor which can make non-detection delay time larger in a minimum circuit structure.SOLUTION: A proximity sensor 10 comprises: a detection section 22 which changes the amount of detection current outputted in accordance with passage of a metal body; a first delay circuit 23 which has a first terminal connected to the detection section, delays first voltage of the first terminal at a first time constant in accordance with the detection current inputted from the detection section, and shifts a detection level from a non-detection level indicative of non-detection of the metal body to the detection level indicative of detection of the metal body; a second delay circuit 24 which is connected to the first delay circuit in parallel, has a second terminal and delays second voltage of a second terminal in accordance with the detection current inputted from the detection section at a second time constant larger than the first time constant to shift the second voltage; a connection changeover section 25 which is arranged between the first terminal and the second terminal and connects the first terminal and the second terminal when the first voltage is the second voltage or larger; and a determination circuit which outputs an output signal indicating whether or not the metal body is detected, in accordance with the voltage level of the first voltage.SELECTED DRAWING: Figure 3 |
