磁调制式直流电流比较仪精密测量应用拓展的探索

Exploration on the application expansion of direct current comparator precision measurement

磁调制式直流电流比较仪依托调制解调技术实现直流电流的高准确度变换,广泛应用于直流电阻、直流大电流及其比例的精密测量。为拓展直流电流比较仪在精密测量领域的应用,提出一种非常规直流电流比例的校准方法,通过二次电流的加减运算,解决标准比例数量受限的问题。通过实际测试,验证该方法的可行性。此外,提出基于直流电流比较仪的直流电阻器电流系数测量方法,通过比例调节的方式满足电流系数定义的同时,还消除了标准电阻器引入的误差。该方法经过四步测量,完成直流电阻值的自比较,得到电流系数的准确数值,具有不依赖上级标准器的特点。

Direct current comparator realizes high accuracy conversion of direct current based on the modulation and demodulation technology,widely used in the precision measurement of direct current resistance,large direct current and direct current ratio.To expand the application of direct current comparator in the field of precision measurement,a calibration method of unconventional direct current ratio was proposed,which solves the problem of limited standard ratio number through the addition and subtraction of secondary current.The feasibility was verified through practical test.Furthermore,a current coefficient measurement method of direct current resistor based on direct current comparator was presented.The definition of current coefficient was satisfied by the ratio adjustment,and the error introduced by the standard resistor was also eliminated.This method completed the selfcomparison of direct current resistance value and obtained the accurate value of current coefficient after four steps measurement,characterized by the independence of superior standard device.