Method and apparatus for measuring the change in capacitance values in dual capacitors
US5594353A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 11, 1995 |
| Grant date | Jan 14, 1997 |
| Priority date | — |
| Expiry date | May 11, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R19/10
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for calculating a ratio, R, having a first capacitance value, C.sub.1, in inverse relation to a second capacitance value, C.sub.2, where C.sub.1 and C.sub.2 are the capacitance values of a first capacitor and a second capacitor respectively. The first and second capacitors each have an independent electrode and share a common electrode. An AC voltage is applied to the common electrode producing first and second AC current signals at the two independent electrodes. A dual switched-capacitor integrated circuit and two current to frequency converters respectively convert the first and second AC current signals to first and second frequency signals having values f.sub.1 and f.sub.2. A microprocessor receives the first and second frequency signals and calculates R from f.sub.1 and f.sub.2.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.