Alternating current comparator bridge for resistance measurement
US4322679A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 1980 |
| Grant date | Mar 30, 1982 |
| Priority date | — |
| Expiry date | Apr 7, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R17/10
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The ac current comparator bridge measures the resistance of an unknown resistor at 50-60 Hz with an accuracy in the order of 10 parts per million. The current in the unknown resistor is compared, using a current comparator, to the current in a reference resistor for the in-phase component, and to the current in a reference capacitor for the quadrature component or phase defect. Once an ampere-turn balance is achieved in the comparator by adjusting the winding turns, the unknown resistor's values are a function of the reference resistor, the reference capacitor, the voltage sources driving the currents through the unknown resistor and the references, as well as the turns of the windings.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.