Evaluations of a Sampling Impedance Bridge

This paper reports our effort to improve a sampling impedance bridge. Custom-modified ac multimeters together with optimized waveform digitizing software enable us to achieve a stability and resolution better than 1 part in 10
⁸
for nominal 1:1 voltage ratios around 1 kHz. We wish to leverage this new sampling capability to build a digital impedance bridge, aiming to derive the capacitance unit from the ac quantized Hall resistance.