Research on the Key Technology of the AC Digital Ratio Bridge
WANG Zhiwei1,3, LI Chengong2,3, YANG Yan3,4, HUANG Lu3,4
1. Institute of Electrical Engineering， Yanshan University，Qinhuangdao，Hebei 066004， China
2. Institute of Electrical and Information Engineering ，Hunan University，Changsha，Hunan 410082， China
3. National Institute of Metrology，Beijing 100029，China
4. Key Laboratory of Electrical Quantum Standards， State Administration for Market Regulation， Beijing 100029， China
Abstract：Based on an automatic auxiliary balancing algorithm for bridges， the digital proportional AC bridge device is improved. The improved digital proportional AC bridge can effectively reduce the influence of the central branch potential on the measurement results， and realize automatic and fast measurement. A high-precision voltage follower is introduced to effectively isolate the analog switch from the bridge and the acquisition card to improve the measurement accuracy. The voltage ratio collected by the capture card is corrected， and the corrected voltage relative proportional error is less than 10 μV/V. The improved digital proportional AC bridge device is compared with the traditional four-terminal AC resistance bridge， and the measurement uncertainty of the digital proportional AC bridge is better than 1×10-5 at typical frequencies.
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2025, Vol. 46 
