| 摘要 |
PURPOSE:To realize optimum exposure in flash photographing by letting switching operation be performed with the transistor depending on the voltage fluctuations of low voltage power source due to strobe charging, and applying resistance changes corresponding to the object distance to the ammeter. CONSTITUTION:When main switch S of strobe is turned ON, main capacitor Mc is charged by low voltage power source E1. On the other hand, immediately after the main switch S is turned ON, the terminal voltage of the low voltage power source E1 drops suddenly, and as the charging of the main capacitor Mc advances, the terminal voltage of E1 is gradually recovered. Therefore, the terminal voltage VR2 of resistance R2 in voltage dividing circuit also varies in proportion to E1. When VR2 reaches a certain voltage V1, transistors TR1, TR2 and TR3 are turned ON, so that the information of variable resistor VR3 coupled to the distance adjusting mechanism may be inputted in photometric circuit. As a result, the angle of swing of the pointer of ammeter may be controlled by the photographing distance, and appropriate exposure may be obtained also in flash photographing. |
