Digital Bridge Voltage Ratio Calibration using an Automated Permuting Capacitive Device

An automated permuting capacitive device (PCD) was developed for the AC voltage ratio calibration of coaxial bridges. For user convenience and measurement accuracy, the permutation of the PCD capacitors was automated using a coaxial multiplexer. Our digital impedance bridge works at frequencies up to 100 kHz, and its voltage ratio needs to be precisely calibrated for impedance ratio measurements. The PCD can calibrate the 10:1 voltage ratio of the bridge for either the inductive voltage divider or the sinewave generators. The voltage ratio calibration using the PCD was studied and verified using reference values.