AC-DC Difference Measurement of 792A at Millivolt Voltage

The ac-dc difference of the ac-dc transfer standard fluke 792A has been calibrated at millivolt voltage in this paper. The 792A is calibrated based on the voltage divider techniques. A cascaded inductive voltage divider (IVD) has been built with using binary inductive voltage dividers (BIVDs) in cascade connection. The ratio errors of the cascaded IVD are calibrated against the self-calibrated BIVD at millivolt voltages. A resistive voltage divider (RVD) which has equal ratio with the cascaded IVD has also been built. The dc and ac ratio errors at low frequencies are consistent. The VDs can trace the small voltages to the thermal voltage converter (TVC) and be used to measure the ac-dc difference of the 792A at mV ranges.