This invention relates to an indicator for showing the discharged voltage of a stroboscope used with a camera.
A photographic stroboscope is generally designed for the discharge of electric energy stored in a discharge capacitor through a flash tube. At the time of discharge, the flash tube sends forth a flash. The intensity of the flash varies with the static energy or voltage stored in the discharge capacitor. To ensure, therefore, a flash having a desired intensity, it is necessary to examine the voltage of the discharge capacitor. In other words, an indicator is needed which shows the voltage of the discharge capacitor.
A known indicator designed to meet this requirement is the type in which a neon discharge tube is connected to the discharge capacitor. The neon discharge tube requiring a certain discharge space is subject to limitations in being rendered compact. Accordingly, considerable difficulties are encountered in fitting a neon discharge tube type voltage indicator for stroboscope into a camera finder. In contrast, an indicator using a light-emitting diode (LED) in place of a neon discharge tube can be built in a camera finder, enabling a camera as a whole to be easily handled, because the LED can be made very compact. However, a larger amount of current is necessary for the LED to be lighted than when the neon discharge tube is lighted. Discharge current required for the neon discharge tube is about 0.01 mA. Whereas drive current of about 1 mA is required for the LED to give off a light. Therefore, direct replacement of the neon discharge tube used with the prior art indicator by a LED results in a noticeable increase in power consumption, namely, a decrease in the life of a dry cell used as a power source of a stroboscope.