| 摘要 |
PURPOSE:To perform supply power regulating operation smoothly by discharging a capacitor at the end of half wave of AC source voltage thereby eliminating hysteresis between the resistance of a variable resistor and supply power. CONSTITUTION:Time constant of a resistor R2 and a capacitor C2 is set such that a three terminal switching element T3 is conducted at the end of each half wave of AC source voltage E. A capacitor C2 is charged through the resistor R2 for every half wave of the AC source E voltage, and the three terminal switching element T3 is conducted at the end of the half wave of AC source E voltage thus discharging a capacitor C1. Consequently, the capacitor C1 is discharged at the end of each half wave even if a variable resistor VR1 has resistance high enough to prevent conduction of a trigger element T2 between half waves and thereby no charge is left in the capacitor C1. |
