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. 09, 1982
Filed:
Mar. 03, 1980
Applicant:
Inventor:
Thomas J Walsh, Hatboro, PA (US);
Assignee:
Leeds & Northrup Company, North Wales, PA (US);
Primary Examiner:
Int. Cl.
CPC ...
G01R / ; G01R / ;
U.S. Cl.
CPC ...
3241 / ; 324115 ; 324131 ;
Abstract
A preamplifier circuit for a voltage measuring instrument which provides for noninteracting span and zero adjustments. Two voltage follower circuits are used. The first produces a current through the output resistor of the preamplifier proportional to the voltage being measured while the second produces a current through the output resistor proportional to a fixed reference voltage. For both amplifiers, the proportionality is adjustable by a potentiometer which modifies the feedback on the first amplifier and the part of the reference used as input to the second amplifier.