Patent
1976-09-02
1979-03-06
Adams, Russell E.
354 60R, G03B 708, G01J 146
Patent
active
RE0299278
ABSTRACT:
In a shutter operating circuit wherein the shutter time is controlled by a photoelectric transducer disposed to receive the light transmitting through the objective lens, there are provided a first amplifier for amplifying the output from the photoelectric transducer, a second amplifier having a high input impedance and operating to generate an output corresponding to the output from the first amplifier, means for feeding back the output from the second amplifier to the input of the first amplifier, a capacitor connected on the input side of the second amplifier for holding the output from the first amplifier in accordance with the opening operation of the shutter of the camera, a first impedance element connected in series with the photoelectric transducer, a second impedance element connected in parallel with the series combination of the first impedance element and the photoelectric transducer, an integrating capacitor for integrating the output from the second amplifier in accordance with the opening operation of the shutter, and a shutter trigger circuit for closing the shutter when the voltage across the integrating capacitor reaches a predetermined [valve] value whereby the exposure time is determined by the output current from the second amplifier.
REFERENCES:
patent: 3626825 (1971-12-01), Years
patent: 3641891 (1972-02-01), Burgarella
patent: 3648053 (1972-03-01), Sato
patent: 3678826 (1972-07-01), Mori et al.
patent: 3690230 (1972-09-01), Mori et al.
patent: 3712192 (1973-01-01), Ono et al.
patent: 3731604 (1973-05-01), Fujii et al.
Adams Russell E.
Helzer Charles W.
Yashica Co., Ltd.
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