Question

如图,R1=R2=R3=1Ω、当s闭合时,电压表v示数是1.0v,当s断开时,电压表v的示数为0.8v,求E和r

Answer 1

E/(r+1.5)=1

E/(r+2)=0.8

解方程组得：

E=2V

r=0.5Ω