A Dual-Channel Calibration System for AC Currents and Small AC Voltages

A new current-comparator-based dual-channel calibration system for AC currents and AC voltages in the millivolt range has been developed. The range of generated currents is 1 mA-5 A, and the range of generated voltages is 1-500 mV. The calibration system in-phase and quadrature expanded measurement uncertainties (k = 2) are within 25 · 10^-6. Although the system has been developed primarily for operation at power frequencies, it is also capable of operating at frequencies up to 1000 Hz with slightly increased uncertainties. The traceability to SI units is established through the calibration of AC voltage by means of AC/DC transfer and DC voltage reference, standard resistor, capacitor, and current comparator ratios.