Differential thermal wattmeter
US4045734A · kind A · utility
2Cited by
4References
7Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 24, 1976 |
| Grant date | Aug 30, 1977 |
| Priority date | — |
| Expiry date | May 24, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R21/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The differential thermal wattmeter for the ac/dc transfer of power includes a differential thermal converter as a "sum and difference" multiplier, with both ac and dc voltage and current signals simultaneously applied to both heaters. DC feedback to the current input speeds up the response and maintains thermal balance between the heaters, so that the output meter becomes a null indicator. This reduces and can eliminate the need for quadratic response. The requirement for exact matching of the thermal converters is also eliminated by effective interchange of the heaters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.