| 摘要 |
PURPOSE:To reliably prevent a rush current by adding a transistor for detecting a power interruption to interrupt a thyristor and a time constant circuit when preventing the rush current by using a parallel circuit of a resistor and the thyristor. CONSTITUTION:A capacitor 7 is charged through a resistor 4 by turning a power source 1 ON, a transistor 8 connected to the primary winding 7 of a transformer 6 is opened or closed, a thyristor 3 is conducted by a signal of the secondary winding 9 to shortcircuit the resistor 4, thereby eliminating a rush current to obtain a stabilized output. At this time, a time constant circuit having resistors 19, 20 and a capacitor 21 and a transistor 23 are added to shortcircuit between the gate and the cathode of the thyristor 3 by conducting the transistor 23 via the charge of the capacitor 5 at the power interruption time, and the state is eliminated through the time constant circuit at the power recovery time. Accordingly, since the rush current is always flowed through the resistor 4, the reliable preventing operation can be performed. |
