惠斯通电桥实验中高灵敏度档位下最佳桥臂电阻的探讨

Discussions on Optimum Bridge Arm Resistance under High Sensitivity of Galvanometer in Wheatstone Bridge Experiment

惠斯通电桥的灵敏度与检流计的灵敏度有关,当检流计灵敏度档位是4×10^(-6)A/格和4×10^(-8)A/格时惠斯通电桥比较容易调节平衡,但是当检流计灵敏度档位是4×10^(-9)A/格时,惠斯通电桥很难调节到平衡的状态。为了解决高灵敏度档位下惠斯通电桥难以调节到平衡的问题,我们在高灵敏度档位的前提下研究了桥臂比和桥臂电阻对实验测量和相对不确定度的影响。当桥臂比R_1/R_2=1/10时,任意的桥臂电阻都可以使电桥平衡,从而测量出待测电阻的阻值。当桥臂比R_1/R_2=1/1时,桥臂电阻处于11 000Ω至13 000Ω时电桥可以调节到平衡。

The sensitivity of Wheatstone bridge is associated with the sensitivity of galvanometer.It is more easier to adjust the equilibrium of Wheatstone bridge when the galvanometer sensitivities are 4×10-6 and 4×10-8 A/lattice than 4×10-9 A/lattice.In order to overcome the equilibrium problems for the high galvanometer sensitivity 4×10-9 A/lattice,the effects of bridge arm ratio and bridge arm resistance on the experimental measurements and relative uncertainties are studied for the high galvanometer sensitivity 4×10-9 A/lattice.When the bridge arm ratio is 1/10,any bridge arm resistances can adjust the equilibrium of Wheatstone bridge,thus measuring values of unknown resistances.When the bridge arm ratio is 1/1,bridge arm resistances from 11 000Ωto 13 000Ωcan adjust the equilibrium of Wheatstone bridge.