| 摘要 |
PURPOSE:To ensure the operation of the power supply reset circuit to prevent the malfunction, by detecting lowering of the voltage itself applied to the contactless switch by a diode, which becomes conductive only near a fixed voltage, to discharge the internal capacitor in a short time at the power break time. CONSTITUTION:In photoelectric switch 1 which controls transistor 31 forming the output circuit by the signal from light projecting and receiving circuit 10, transistor 21 is inserted in the signal line, and resistance 24 and capacitor 25 are connected in series on the power supply line between resistance 14 for voltage drop and the power supply line in the light projecting and receiving circuit 10 side of resistance 14, and transistor 23 is turned on by charging of capacitor 25 to turn on transistor 21, thereby preventing the malfunction at the power supply time. Diode 27 which becomes conductive only near a fixed voltage is connected to the line in the power source side of resistance 14 to discharge voltage stabilizing capacitor 13 rapidly at the power off time, thereby preventing the malfunction at the reset time. |
