惠斯通电桥实验中对互易桥臂测量结果的不确定度评定

摘要

在惠斯通电桥实验中，采用互易桥臂法测量电阻，常采用2种传统方法评定不确定度，但结果比标准电阻的标准不确定度还小，其原因是互易桥臂的前后两次测量不是完全独立，它们是同一待测量用同一仪器以不同方法测量的结果。改进的测量方法中，B类不确定度由方和根法计算，B2类不确定度等于标准电阻的不确定度。%In the Wheatstone bridge experiment ,the exchanging bridge arm method was used to measure resistance .Two traditional methods were often used to assess the uncertainty .However ,the results was smaller than the standard uncertainty of the standard resistance ,it was because the last and next measurement by exchanging bridge arm were not fully independent ,the two results were of the same quantity measured by the same instrument in a different way .In the improving measurement method ,class B1 uncertainty could be calculated by the root of square sum ,class B2 uncertainty equals to the uncertainty of standard resistance .