Method and circuit arrangement for measuring a capacitance

US8155903B2 · kind B2 · utility

Assignee

• Huf Hülsbeck & Fürst GmbH & Co. KG · DE

Inventors

• Franz Weber · Wiesloch, DE
• Martin Witte · Ahaus, DE

Key dates

• Filing date: Apr 13, 2007
• Grant date: Apr 10, 2012
• Expiry date: Apr 2, 2029

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/24
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method of measuring a capacitance, wherein a voltage across the capacitance is supplied to an input of an evaluation circuit that is designed so that it can detect input voltages with a predetermined degree of precision so long as these voltages are in a measurement interval, includes charging the capacitance to a predetermined starting voltage which exceeds a multiple of an upper limit of the measurement interval. The capacitance across a predetermined resistance is discharged for a predetermined time period. The voltage across the capacitance reaches a final voltage value which is dependent upon the amount of the capacitance. The resistance and the time interval are so chosen that the final voltage value lies in the measurement interval. The final voltage value is detected by the evaluation circuit and the capacitance is determined from the final voltage value. A circuit arrangement for measurement of a capacitance of a capacitor is also disclosed.