PHOTOGRAPHIC FLASH DEVICE

摘要

An improved photographic flash device of the type in which a photometric circuit exposed to light reflected from a subject being photographed generates a photometric signal which controls the amount of light emitted by the flash discharge tube of the device. A synchronizing switch closed by opening the shutter of the camera with which the device is employed activates a starting circuit to generate a starting signal, which in turn starts a timer powered by the low tension circuit of a DC-DC converter utilized in the flash device. The timer applies a constant voltage to the photometric circuit for a predetermined period of time. Both the starting circuit and timer are capable of reduction to integrated circuit form.