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:
Jul. 22, 1980
Filed:
Jul. 12, 1978
Masamichi Furukawa, Yokohama, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
An electronic shutter driving device has a logarithmic expansion circuit which includes no semiconductor element such as a transistor and a field-effect transistor and comprises an operational amplifier, a series of resistors connected to an inverting input terminal of the operational amplifier, a plurality of capacitors interconnected between the inverting input terminal of said operational amplifier and the junctions, respectively, between the resistors and an integrating capacitor interconnected between the inverting input terminal and output terminal of the operational amplifier, a source voltage being applied to the output terminal or a reference voltage input terminal of said operational amplifier.