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. 05, 1997
Filed:
Jul. 03, 1996
Board of Trustees operating Michigan State University, East Lansing, MI (US);
Abstract
A constant temperature anemometer utilizes a fine wire or thin film sensor or probe and a pulse width modulated driver in a digital control loop to adjustably drive the probe to maintain its temperature at a nominally constant value and provide a digital output to associated metering or recording equipment. The pulse width modulated driver includes a clock, an RS flip-flop and a comparator. At the beginning of the clock cycle, power is provided to a voltage divider and the divided voltage drives one input of the comparator and the fine wire or thin film sensor. The other input of the comparator is maintained at a reference voltage. When the drive voltage to the hot wire or thin film sensor exceeds the reference voltage, the comparator provides a high logic signal to the RS flip-flop, resetting it and shutting off power to the sensor until the next clock cycle. The pulse width modulated drive signal may be utilized directly by an associated processor or computer. Various circuit features may be added to improve operation given specific installation or operating parameters.