一种高精度交流电桥自动辅助平衡方法

An Auto Source Balance Method of High Precision AC Bridge

提出一种用于高精度交流感应耦合比率臂电桥的自动辅助平衡方法。该方法在原理上对交流电桥的测量精度的影响可忽略,只需简单完成电桥主平衡,即可实现同类型阻抗的精密比较和测量,极大提高了电桥的收敛速度。该方法在为我国新计算电容装置研制的电容电桥中得到应用,电容传递在1592Hz的不确定度指标达到3×10-8(k=1)。

An auto auxiliary source balance method is proposed and achieved. The impact of this method on the measurement accuracy ofthe auto source balance circuit is negligible. And the method can greatly improve the convergence speed of the AC bridge′s balance procedure A high precision coaxial AC bridge is constructed at NIM for high precision capacitance transmissiononly by the auto source balance method. The bridge can transmit capacitance with an uncertainty of 3×10-8（k=1） at 1592Hz.