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:
May. 13, 1997
Filed:
Apr. 04, 1996
Reinhard Tielert, Winnweiler, DE;
Andreas Hildebrandt, Speyer, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
In a circuit arrangement for determining differences in capacitance, two capacitors (1,2) are alternately connected to an integrator with differential amplifier (3) whose input current is positive (+I) when the first capacitor (1) is integrated or negative (-I) when the second capacitor (2) is integrated, whereby the switches (5,6,7) are synchronously switched. The differential amplifier keeps the voltages at the two capacitors the same. A clocked control device (4) controls the synchronous switching and separately measures and adds the respective charging and discharging times and, as warranted, measures and adds the output voltage of the integrator and controls the last charging cycle such that the voltage at the capacitors is subsequently equal to the initial voltage. The relative or absolute differences in capacitance are calculated from the identified sums and can be digitally output.