Error Analysis of Improved Current-bridge Method for Accurate Low-impedance Measurement

Abstract

The improved current-bridge method and its mathematical model are proposed for accurate low-impedance measurement. To realize the accurate measurements of shunt resistors smaller than 1 mΩ, the expansion of current ratio of a current transformer and a current comparator, the use of low-value resistance for reference impedance, and the development of a buffer amplifier which have flat load characteristics are required. The improved current bridge-method has the possibility for accurate measurement of shunt resistors up to 10 µΩ.