| 摘要 |
PURPOSE:To prevent operation from having uncertainty even at the time when a contact point was closed due to chattering, etc., by providing a resistance having a prescribed constant relationship with a capacitor connected to the contact point. CONSTITUTION:When a contact point S1 of a circuit A is opened, the current assin from the contact point (CP)S1, to a grounding GND through a resistor R and a rectifier CR1 starts flowing toward a resistor R1, a rectifier CR2 and a capacitor C1, and voltage at a point gamma rises rapidly at a time constant to be determined by the resistance R1 and the capacitor C1. The voltage at a point gamma puts out a signal which operates an SCR control circuit (circuit B) by a resistance R2. By making constant relationship between the capacitor and the resistance R1.C1<R2.C1, the electric charge stored in the capacitor C1 is allowed only to be discharged through the resistance R2 even at the time when the contact point S1 is closed due to chattering, etc, and the current is not allowed to pass in the direction of the contact point S1 by the rectifier CR2, whereby uncertainty of operation due to chattering, etc. can be eliminated. |
