Stable source of AC voltage and current

A stable source of AC voltage up to 120 V and current up to 6 A is developed and built. The stability of the source monitored over several minutes is far under 10 ppm of full scale for voltage, current and power, and in the range of 10 ppm of full scale for voltage and current and 20 ppm of full scale for power over several hours, with the phase angle instability less than 3 /spl mu/rad during a 30 minutes interval. The high stability of the output quantities qualifies this instrument as a stable laboratory source of AC voltage, current and "phantom" power and as a phase angle standard using a simple auto-calibration method described in the paper. As the instrument has full computer control over an extended set of parameters, this two-channel source can also be used as the development base for various techniques, methods, instruments and systems for precise AC measurements.