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. 24, 2004
Filed:
Oct. 12, 2001
Alex David Colvin, Oak Park, MI (US);
Joseph C Cassatta, Taylor, MI (US);
Ford Global Technologies, LLC, Dearborn, MI (US);
Abstract
A conductivity sensor ( ) and control circuit ( ) for determining the conductivity of a fluid is provided. Conductivity sensor ( ) is formed of a first annular electrode ( ) spaced apart from a second annular electrode ( ) having a tubular portion ( ) therebetween. The first annular electrode ( ) and the second annular electrode ( ) are coupled to a control circuit ( ). The control circuit ( ) preferably includes a square wave generating circuit ( ), a current-to-voltage converter circuit ( ) coupled to one of the electrodes, a buffer circuit ( ) coupled to the other one of the electrodes, a synchronous detector circuit ( ). The synchronous detector circuit ( ) is operated using the square wave from square wave generator circuit ( ). By oscillating between a negative and positive gain, a constant direct current output corresponding to the conductivity of the fluid between the first annular electrode and second annular electrode is provided.