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:
Aug. 28, 1990
Filed:
Oct. 13, 1989
Applicant:
Inventor:
Donald L Mueller, Dayton, OH (US);
Assignee:
General Motors Corporation, Detroit, MI (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G08B / ; H01G / ;
U.S. Cl.
CPC ...
340620 ; 7330 / ; 7330 / ; 361284 ;
Abstract
A washer fluid monitor comprising a pair of electrically conducting probes projecting downward into a washer fluid reservoir and incorporated into part of the positive feedback loop of a Wien bridge oscillator. One of the probes is grounded; and the Wien bridge oscillator is modified with an additional capacitor isolating the other probe from the DC supply and intermediate voltages so that it is essentially grounded at the oscillator frequency to greatly reduce or eliminate ionic currents in the washer fluid and resulting probe degradation without the need for an isolating transformer.