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. 24, 1984
Filed:
Feb. 26, 1982
Ronald A Gatten, Placerville, CA (US);
Paul L Patterson, Walnut Creek, CA (US);
Delta Associates, Inc., San Jose, CA (US);
Abstract
A gas stream detection apparatus having a balanced resistive bridge network enclosed within a housing and an electronic power supply for driving the bridge network. The power supply includes a voltage source feeding a voltage-to-current converter with two differential inputs, a current sensing resistor between the converter and bridge, twin feedback paths to the differential inputs, and a large source resistance connected to the voltage source and in parallel with a smaller source resistance, each connected to separate differential inputs. The resistance R of two bridge filaments increase by .DELTA.R when exposed to high sample gas concentration causing variations in a current I supplied to the bridge. As .DELTA.R increases, a bridge output voltage E.sub.O decreases. The dependence of current I on .DELTA.R depends on circuit parameters. The difference between the source resistances permits the voltage source to be non-constant and load dependent. The source output polarity opposes the feedback polarity and under steady state a fixed current I exists. When sample concentration increases, the feedback input decreases causing current I to increase which restores detector sensitivity and provides a linear output voltage response E.sub.O.