基于电流比较仪的四端钮阻抗电桥  

Four-terminal impedance bridge based on current-comparator

作　　者：曲正伟[1,2] 王云静[2] 

机构地区：[1]清华大学精密测试技术及仪器国家重点实验室,北京100084 [2]燕山大学电气工程学院,秦皇岛066004

出　　处：《仪器仪表学报》2011年第9期1987-1992,共6页Chinese Journal of Scientific Instrument

基　　金：清华大学精密测试技术及仪器国家重点实验室开放基金项目(No.DL-005)资助

摘　　要：为了能够精确测量四端钮形电阻,提出一种用于交流电阻标准量值传递的电流比较仪四端钮阻抗电桥,该电桥由同步电压源供电,采用前馈网络与反馈网络共同作用的方式来调节和维持电流比较仪主铁芯的磁势平衡,利用数字锁相放大器读取被测阻抗与标准阻抗间的电压差别,通过计算可间接求得两者的交流阻抗差。利用所研制的电桥对3只1 000Ω双螺线型可计算电阻间的交、直流相对差进行比较测量,1592 Hz及以下频率时的测量不确定度为3×10-7,满足交流电阻标准量值传递的要求。This paper presents a current-comparator based four-terminal impedance bridge for quantity value dissemination of national AC resistance standard. The bridge applies a synchronous voltage source as the power supply and balances the magnetomotive force of main magnetic core through adjusting feed-forward and feed-back networks. Once the balance is obtained, a digital lock-in amplifier gets the voltage differences between the measured element and the standard, and then their impedance difference can be calculated indirectly using the difference values. The AC/DC relative differences of three double helix resistors are measured at the frequencies equal and below 1 592 Hz with the proposed bridge using substitution method; and the measurement uncertainty is about 3 × 10^-7.

关 键 词：电磁计量 电流比较仪 量值传递 双螺线型电阻器 

分 类 号：TB971[一般工业技术—计量学]