Stable capacitive pressure transducer system
US5233875A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 4, 1992 |
| Grant date | Aug 10, 1993 |
| Priority date | — |
| Expiry date | May 4, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L9/125
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A stable pressure transducer system is disclosed. The transducer system includes a variable capacitor having conductive plates with one of the conductive plates being associated with a diaphragm variable under pressure changes to vary the capacitance of the variable capacitor. The system also includes a reference capacitor. Circuitry for applying signals to the pressure variable and the fixed reference capacitor is used to obtain outputs from each of the capacitors with the output from the variable capacitor varying in amplitude with its capacitance. Circuitry for differentially combining the outputs from the variable and fixed capacitors provides an output voltage indicating the pressure applied to the diaphragm. In order to stabilize the output of the transducer, an isolating capacitor having a capacitance value at least several times greater than the capacitance of the variable and reference capacitors is coupled in series with one or both of the variable and reference capacitors. Preferably two isolation capacitors are used, one in series with each of said variable and reference capacitors on either side thereof. However, in some cases a single isolating capacitor between a com…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.