| 摘要 |
PURPOSE:To perform accurate dimmer operation excelling in stability and sensitivity, by supplying power source simultaneously with power supply to DC-DC converter circuit, and operating to force the flash discharge deivce to emit light. CONSTITUTION:When a power switch 2 of DC-DC converter circuit is turned on, a switch 10 is also turned on in cooperation, so that a power source 11 may be supplied. However, since a transistor 17 is in conducting state, the potential of an integrating capacitor 16 is regarded to be about zero. Afterwards, when an electric charge is accumulated in a main discharge capacitor 4 and a flash discharge tube 6 is caused to emit light by the operation of a trigger circuit 5, a photo detector 15 receives the light reflected from the subject, and charging of the integrating capacitor 16 is started in proportion to the quantity of light thus received. When this charged voltage reaches a specified voltage, the emission of the flash discharge tube 6 is stopped, thus returning to the state before operation. Thus, dimmer operation of high stability, excellent sensitivity, and high accuracy may be achieved. |
