| 摘要 |
PURPOSE:To shorten the queuing time of charging of a capacitor by stopping the discharge of the capacitor when the intensity of light is damped and reduced to a value which does not contribute to the change of a sensitive material. CONSTITUTION:When the intensity of light of an electronic flash discharge tube 3 is reduced to a value, which does not contribute to the change of a sensitive sheet B, in the damping process after the time when this intensity of light has a maximum value with one discharge, the charging voltage of a main capacitor Cm is reduced to a preliminarily determined prescribed value, and this reduction is detected by a comparator 24. Then, the comparator 24 outputs a turn-on signal to a gate terminal G3 of a thyristor S3, and the charged electric charge of a capacitor C2 is applied as a reverse bias voltage between the anode and the cathode of a thyristor S2 through the thyristor S3, and the thyristor S2 is turned off. The arc discharge of the electronic flash discharge tube 3 is stopped, and the discharge of the main capacitor Cm is stopped in accordance with this stop. |
