| 摘要 |
PURPOSE:To prevent the gate of a thyristor from a impression of electric charge due to natural discharge by connecting an one-way conductive element to a natural discharge loop including the thyristor of a commutation capacitor. CONSTITUTION:If the quantity of light guaranteeing proper exposure is not obtained even by full light emission in case of inner light emission at the time of inner light photographing using an inner light tube 20, the thyristor 28 is held off state. Since the charge of the commutation capacitor 23 is not discharged through the thyristor 28, a loop consisting of resistors 82, 81, a capacitor 7, a diode 45, and resistors 44, 43 is formed as a discharge route for the charge of the capacitor 23 and the charge of the capacitors 6, 7 may be continuously discharged through a thyristor 42. Since a diode 41 to be used as an one-way conductive element is arranged in the loop of the capacitor 23, said loop is interrupted by the diode 41 and the thyristor 42 is prevented from ON operation at the timer of full light emission. |
