| 摘要 |
PURPOSE:To reduce the power consumption, by inputting the voltage for switching state detection of contacts to a comparator via a protective diode and a filter and charging the capacitor for filter through a charging resistor. CONSTITUTION:The voltage to detect the switching state of contact 1-2 is fed to a comparator 5-1 via a protective diode 5-3 and a resistance 4-1 and a capacitor 4-2 for filter, to output 0, 1 signal according to the switching of the contact 1-2. Further, the capacitor 4-2 is charged via a transistor 4-7 turned on only when the input contact changes from open position to closed position, and via a charging resistance 4-4. Thus, a large rush current can flow since the resistance 4-1 can be selected as small. Further, the power consumption can be reduced since the resistance 3-1 can be selected as a large value. |
