| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the necessity of selecting a battery having a high nominal voltage to drive a load which conducts mechanical operations such as moving a diaphragm of an automatic exposure mechanism, to eliminate a complex circuit to obtain large driving current, to suppress cost increase caused by these loads and to prolong the service life of a battery. SOLUTION: In an automatic exposure mechanism driving power supply circuit 20 of a constant voltage automatic rechargeable stroboscopic circuit 100, AC voltage generated at the collector of an oscillation control transistor Q1 connected to the primary side of a boosting transformer T1 is rectified by a rectifier diode D4 to generate DC current and filtered by a capacitor C3 to obtain DC secondary power source. The DC secondary power source is boosted through a transistor Q2 which is turned on and off by an external light beam quantity discriminating phototransistor PH1 to obtain a voltage that is higher than a battery voltage VB and supplied as a driving power supply of a diaphragm control solenoid RE1.
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