Abstract：Based on an automatic assisted balancing algorithm for ac bridges, the ac digital ratio ac impedance bridge has been improved. It can effectively reduce the influence of the center point potential on the measurement results, and realize the automatic and fast measurement. A high-precision voltage follower is adopted to isolate the analog switch from the bridge and the acquisition card to improve the measurement accuracy. The voltage ratio collected by the acquisition card is corrected then the final relative voltage ratio error is less than 10 μV/V. The improved ac digital ratio bridge is compared with the traditional four terminal-pair ac resistance bridge, and its measurement uncertainty is in the level of 10-6 at the typical frequencies.
2025, Vol. 46 
