Current developments in accurate AC-DC transfer measurements
- Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)
Recent improvements in commercial ac instruments led to new activities in the field of basic standards for ac-dc transfer measurements. Current developments are discussed in this paper. The new generation of instruments uses sampling methods, solid state thermal converters or analog log-feedback conversion for the detection of the rms value of ac voltage and current, New designs of the input dividers and wide-band and stable amplifiers for low voltages enlarge the voltage ranges from mV to 1000 V and the frequency range from 10 Hz to 1 MHz. The measurement uncertainty of calibrators, measuring instruments and ac-dc transfer standards approach the ppm level. This leads worldwide to activities in the national laboratories which aim at providing traceability to national standards with adequate uncertainties. Ac-dc transfer standards, based on thermal converters, provide the most accurate link between ac and dc voltage and current. For many decades the uncertainty of the thermal converters in the national laboratories was several ten times lower than that of commercial instruments. Modern instruments shorten this distance to less than 5.
- OSTI ID:
- 125817
- Report Number(s):
- CONF-940603--
- Country of Publication:
- United States
- Language:
- English
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