Abstract：A new type calculable capacitor with a movable guard rod has been built in National Institute of Metrology of China at the standard uncertainty of 2×10-8. The SI unit of capacitance reproduced by the calculable capacitor depends on the axial length which is measured by a laser interferometer. However the huge integral number of the fringe is in general not given by the laser interferometer. In a classical approach the substitution measurements were adopted to extend the integral number from a known smaller value to the bigger one. It needs some additive devices and complex operations. A novel approach is proposed. The required integral number is determined by the other capacitance standard with a lower accuracy, and the decimal number is determined by the capacitance bridge with a transfer capacitor. The details of this approach and its advantages are presented. An experiment to check the linear is reported.
陆祖良,黄璐,杨雁,赵建亭,钱进,陆文骏,刘忠有,张钟华,刘秀英,王建波,王维,何小兵. 可动屏蔽型计算电容复现电容单位的方法研究[J]. 计量学报, 2014, 35(6): 521-527.
LU Zu-liang,HUANG Lu,YANG Yan,ZHAO Jian-ting,QIAN Jin,LU Wen-jun,LIU Zhong-you,ZHANG Zhong-hua,LIU Xiu-ying,WANG Jian-bo,WANG Wei,HE Xiao-bing. Research for Reproducing SI Unit of Capacitance by the Calculable Capacitor with a Movable Guard Rod. Acta Metrologica Sinica, 2014, 35(6): 521-527.
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2014, Vol. 35 
