Question

如图所示,电压表量程为0~3V,电流表量程0~0.6A,滑动变阻器R2的最大阻值为15欧,电阻丝R1阻值为5欧,电源电压

Answer 1

电流

I总 = U/R

= 4.5 / (5+R2)

I总 =< 0.6

4.5 / (5+R2) = ,< 0.6

R2 >= 2.5

U表 =[ U / (R1+R2) ]* R2

=[ 4.5/( 5+R2) ]* R2 =< 3

R2 =< 10

R2 在 [ 2.5 ,10 ] 变化