Capacitive measuring transducer
US4481465A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 27, 1981 |
| Grant date | Nov 6, 1984 |
| Priority date | — |
| Expiry date | Mar 27, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R27/2605
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Capacitive measuring transformer, especially for small capacitance values, with two parallel bridge arms, connected with an oscillator, each of which has at least one capacitor, whereby a differential amplifier is provided which is connected on the input side with the bridge arms and the input of which is connected by a feedback circuit, containing passive elements only to one of the bridge arms. A control element (D.sub.1, D.sub.2) precedes every one of the bridge arms and a fixed potential or a potential changing inversely in relation the outlet of said differential amplifier, (OA.sub.1) is applied to the second bridge arm. As a result, one will moreover achieve a high measure of stability and linearity between capacitance and output voltage. The fixed potential is used when the feedback is to one bridge arm only. The potential changing inversely in relation to the output of the differential amplifier (OA.sub.1) is used when the feedback to both bridge arms gives the highest degree of stability and linearity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.