A.毫安表A1(量程10mA,内阻为100Ω)
B.毫安表A2(量程120mA,内阻为20Ω)
C.定值电阻R1=5Ω
D.定值电阻R2=0.1Ω
E.定值电阻R3=200Ω
F.定值电阻R4=1400Ω
G.滑动变阻器R
H.开关、导线若干