JPS5639531A - Automatic dimming storobe device - Google Patents

Abstract

PURPOSE:To discriminate whether exposure is correct or not prior to film printing and prevent the failure in photographing by providing the correct emission announcing means which discriminates and displays whether the emission stop signal generating timing is correct or not. CONSTITUTION:On emitting of light, one input potential of comparators 14, 15 begins to rise at a different time constant. Another input potential of both comparators is equal and remains nearly constant during lighting of a neon tube 19. After the neon tube goes off, said potential gradually lowers according to the voltage of a main capacitor 2. When both input potentials become equal (time T1), the comparator 14 inverts to turn a transistor 13 off, thereby enabling a light emitting element 12 to emit light. Next, when both input potentials of the comparator 15 become equal (time T2), the TR13 reconducts. Hence, if the emission stop signal is generated between the time T1 and T2, 12 is lighted by charging of a capacitor 11 owing to turning-off of an SCR4, but even if the stop signal is generated at the timing other than this, 12 does not light.