Improved Automated System for AC Voltage Calibrations Using Extending Range Resistors
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Some improvements are presented in this paper to the previously introduced automated multi-range multipliers system. These multipliers; range resistors are selected automatically by using electronic relays controlled by a micro-controller that connects the suitable multiplier to the thermal voltage converter to calibrate the required ac voltage. The modifications done on the old system are mainly in used resistors and connectors. The ac–dc transfer differences for the improved and the old multipliers systems combined with the same thermal converter are determined automatically against another standard thermal voltage converter. The obtained ac–dc differences results and their repeatability; Type A for both systems are compared to evaluate the performance of the new one. The new system introduces a better performance, smaller ac–dc differences and Type A, especially in the high voltage and frequency ranges.
KeywordsAC voltage measurement Thermal voltage converter Multipliers AC–DC transfer difference Uncertainty
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