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:
Apr. 11, 1995
Filed:
Jul. 30, 1993
Bernd Scheler, Bad Orb, DE;
Dieter Ehlers, Muhlheim, DE;
Honeywell AG, Offenbach, DE;
Abstract
A capacitive humidity sensor circuit in which a one-shot circuit produces pulses having a pulse duration determined by the capacitance of a capacitive sensing element, the one-shot circuit being triggered by the trailing edges of pulses in a pulse train produced by a multivibrator. The multivibrator is adjustable to produce a pulse train of variable repetition rate independent of the value of the measured parameter. The pulses produced by the one-shot circuit are integrated to produce a voltage indicative of the time average value of the pulses, the voltage being supplied to an amplification and offset compensation circuit whose output signal is used to adjust the supply voltage to the multivibrator so as to effectively achieve compensation for nonlinear response of the capacitive sensing element to increasing relative humidity.