| 摘要 |
PURPOSE:To achieve the simplification of circuit constitution by absorbing part of the surge vlotage generated at the discharging of a commutating capacitor into a sub-capacitor and letting the same be a reverse bias for the main SCR. CONSTITUTION:When a power source circuit is operated, a main capacitor C13, sub-C47, commutating C56 are charged. Next, when a trigger switch 13 is closed, the trigger voltage is applied from the C9 to an SCR35, and a discharge tube 17 is triggered. The accumulated charges of the main C13 abruptly discharge, causing the discharge tube 17 to emit light and the subject to be thereby lighted. When the discharging of the sub-C47 is accomplished and current flows to an impedance circuit, a driving voltage is applied to a dimming circuit 49 upon the light emission operation of the discharge tube 17. When a light emission stop signal is generated in output end 49b, the accumulated charges of the commutating C56 are discharge through the sub-C47. Because of this, the surge voltage, part whereof has been absorbed by the C47, is applied as a reverse bias to the main SCR 54. |
