A three-arm four terminal-pair digitally-assisted current comparator bridge for the comparison of arbitrary complex impedances

We present here a current comparator impedance bridge that can perform comparisons of unlike impedances. The bridge has three arms, and each of the three standards is defined as a four terminal-pair impedance. The bridge is digitally-assisted and is driven by a multichannel digital sine wave synthesizer. The architecture minimizes the number of components and the measurement procedure is semi-automated. Results of test calibrations of both pure and impure impedances are reported.