| 摘要 |
PURPOSE:To prevent a switching element such as a thyristor from malfunctioning even a large noise is applied, by charging a capacitor with a constant current and operating the switching element by the voltage across the capacitor. CONSTITUTION:Once the voltage between +V and -V exceeds a rated voltage value, a constant voltage diode ZE conducts, and then a constant current diode 3 also conducts to output a constant current I0. Consequently, the capacitor C3 is charged with the constant current and the thyristor CR turns on a specific time t0 later to detect an overvoltage. Thus, the time until the thyristor CR turns on is made invariably constant by the constant current diode 3, so no malfunction caused by a noise occurs regardless of the level of the noise. |
