The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 12, 1980
Filed:
Jun. 29, 1978
Takashiroh Iwasaki, Tokyo, JP;
Jun-ichi Mameda, Kodaira, JP;
Hitachi, Ltd., , JP;
Abstract
A photometric amplifier circuit, having a photocurrent converting element connected between a pair of inverting and noninverting input terminals of a differential amplifier, for amplifying an electric signal responsive to the quantity of light, is characterized in that a differentiating circuit is connected between the inverting input terminal of the differential amplifier and a power supply to thereby prevent the differential amplifier from producing an undesired latch output when the power is supplied from the power supply, with the result that, after this power is supplied, a normal amplifying operation is capable of being obtained at an earlier time. This invention is particularly adapted for an automatic exposure control system for cameras to precisely control the exposure of the camera.