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:
Oct. 06, 1992
Filed:
Jun. 17, 1991
Applicant:
Inventors:
Earl B Hoekman, Roseville, MN (US);
Steven M Hamer, Willernie, MN (US);
Assignee:
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R / ;
U.S. Cl.
CPC ...
324655 ; 324654 ; 32420716 ; 340941 ; 331 65 ;
Abstract
An inductive sensor is driven by a series resonant oscillator circuit to produce an oscillator signal having a frequency which is a function of inductance of the inductive sensor. An inductive load, which includes the sensor, is connected in series with a capacitive impedance. Power to the series resonant circuit formed by the inductive load and the capacitive impedance is controlled as a function of current in the series circuit as sensed by a current sensor. A detection system provides a detector output based upon the frequency of the oscillator signal.