Patent
1974-07-11
1976-06-15
Hix, L. T.
354 60E, 354 60L, G03B 708
Patent
active
039640760
ABSTRACT:
In a shutter speed display device for use in combination with an electric shutter operating circuit of a photographic camera wherein an electric signal produced by a photosensitive element and corresponding to the brightness of an object is used to operate the shutter of the camera, there are provided an improved electric shutter operating circuit which comprises a first amplifier for amplifying the electric signal, a second amplifier comprising a field effect transistor connected to amplify the output from the first amplifier, a first impedance element connected between one terminal of the photosensitive element and the negative pole of a DC source, a second impedance element connected in parallel with the series circuit including the photosensitive element and the first impedance element, and a transistor connected to the output of the second amplifier for feeding back the output to the input of the first amplifier; and shutter speed display means determined primarily by the ratio of the value of the resistance of resistor 9 to resistor 10. The shutter speed display means preferably comprises comparator means connected to the source of the second, field effect transistor amplifier and to a reference voltage source so as to respond to a signal having the same phase as that of the input to the second, field effect transistor amplifier and the same magnitude as a selected reference voltage, and means responsive to the output from the comparator means for displaying a predetermined shutter speed.
REFERENCES:
patent: 3603799 (1971-09-01), Nobusawa
patent: 3648580 (1972-03-01), Yanagi et al.
patent: 3678826 (1972-07-01), Mori et al.
patent: 3712192 (1973-01-01), Ono et al.
patent: 3798662 (1974-03-01), Suzuki
patent: 3800305 (1974-03-01), Ogiso et al.
patent: 3812503 (1974-05-01), Engelsmann et al.
patent: 3818495 (1974-06-01), Sagara et al.
patent: 3877039 (1975-04-01), Ichinohe et al.
Ichihashi Osamu
Muramatsu Sadao
Helzer Charles W.
Hix L. T,.
LaBarre James
Yashica Co., Ltd.
LandOfFree
Shutter speed display devices for electric shutter operating cir does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Shutter speed display devices for electric shutter operating cir, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Shutter speed display devices for electric shutter operating cir will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1698458