EXPOSURE CONTROL CIRCUIT OF CAMERA

摘要

PURPOSE:To prevent the charging current of a capacitor from becoming excessive, and slow down voltage rising and adjust a shutter trigger switch and the start of opening operation easily by connecting a resistance with a properly large resistance value to a CdS photodetecting element in series. CONSTITUTION:An exposure control circuit has the high brightness correcting resistance connected to the CdS in series. The capacitor voltage (t) rises slowly with regard to the input and output of the comparator 6 of this control circuit and the opening waveform of a shutter, and time differences T1 and T2 are adjusted extremely easily even with high brightness. The resistance value Rs of the resistance 8 is set preferably so that 0.5REV10017<=Rs<=2REV10017, where EV10017 is the quantity of light and REV10017 is the resistance value of the CdS. This is applied similarly to a control circuit which performs discharge through a CdS.