半偏法测电表内阻的理论误差分析及实验改进

Theoretic Error Analysis and Ways to Improving the Half-deviation Method for Measuring the Ammeter Internal Resistance

实验方法的不完善或测量原理所依据的理论具有一定的近似性 ,使得测量结果存在理论误差。如采用符合实际的理论公式 ,并保证实验仪器所必需的使用条件 ,就可以消除理论误差。文中分析了用两种不同的“半偏法”测量电表内阻的理论误差 ,给出了消除理论误差的改进方案。其实验测量中的关键就是 :两种不同测量方法均应控制操作“半偏”前后的电路中总电流不变 ,从而使测量结果较为准确 ,误差降至最小。

Limitations of experiment methods and approximation of measuring principles result in theoretic errors in measuring.However,such errors can be eliminated by exploiting proper and practical theoretic formulas and by ensuring the precision of the experiment equipment.In this paper,the theoretic errors resulted from the measuring of the internal resistance of the ammeter by two different Half deviation methods are systemically analyzed and an improved scheme to eliminate the errors is given.The authors point out that the critical tache of the experimental measurement is that the whole electric current in the circuit before and that after the half deviation should be controlled to be consistent in either of the two different measurements,which ensures the precision of the outcome and minimizes the errors.