Patent
1975-04-22
1976-06-01
Hix, L. T.
354 51, 354 60R, 354235, 354258, G03B 708, G03B 962
Patent
active
039613380
ABSTRACT:
In a device including a light measuring circuit having a photocell for receiving light from the object to be photographed to give an output and operable to convert the output to a voltage proportional to the logarithm of the intensity of the light, a memory capacitor for storing the output voltage of the circuit, an antilogarithmic conversion transistor for subjecting the voltage stored in the capacitor to antilogarithmic conversion to produce a current in proportion to the light intensity, a capacitor for integrating the current simultaneously with the initiation of opening of the shutter, and a control circuit for giving an exposure time under the control of the voltage charged in the capacitor, the improvement comprising a first switch and a second switch arranged in series with each other and provided between the emitter of the transistor and the connection of the emitter to a lead wire extending from one terminal of a power source, the switches being so positioned that only the emitter current of the transistor passes through the switches. The first and second switches are opened and closed in response to the operation of the shutter.
REFERENCES:
patent: 3815148 (1974-06-01), Ikeda et al.
patent: 3831180 (1974-08-01), Tsujimoto
Adams, Jr. Russell E.
Hix L. T,.
Minolta Camera Kabushiki Kaisha
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