Phase angle standards and calibration methods

Phase angle is one of the quantities that describes the properties of ac circuits. Its measurement is important in a wide variety of applications which include analysis of feedback amplifiers, servo-systems, communications circuits, oscillator and filter circuits, transformer characteristics, and other applications ranging from navigation to power systems and even to plasma physics experiments. Accuracy requirements differ widely for many of these applications, but from the point of view of the standards laboratory, calibration accuracy must be sufficient to handle precision commercial phase-angle meters with typical measurement uncertainties of 0.05 degrees and resolution of 0.01 degrees. Calibration methods and the accuracy thereof are discussed.