单电桥的灵敏度及测量误差

Sensitivity and Error of Single Bridge

用两种不同方法导出了单电桥的相对灵敏度计算公式 ,分析了影响相对灵敏度的各种因素 .并在此基础上讨论了滑线电桥的灵敏度及其对所测电阻 Rx 的影响 ,从理论上给出了滑线电桥最小相对误差的条件 :要使滑线电桥灵敏度所引起的相对误差最小 ,电桥平衡点的位置应按待测电阻 Rx 与检流计内阻 Rg 的比值来确定 .从而 ,为实验时通过选择最佳桥臂比

By using two kinds of methods,the formula on the relative sensitivity of single bridge is given.All factors affecting relative sensitivity are analyzed.The sensitivity of slide bridge and its influence on the measured resistance Rx are discussed.The condition of the minimum relative error is theoretically given.Thatis the place of the balance point should be chosen according to the ratio of the measured resistance Rx to the internal resistance Rg of the galvanometer in order to get the minimum relative error.Thereby,the theoretical evidence is offered to cutdown experimental error by choosing bestratio N.