①电流表G1(0~50mA,内阻r1=3Ω)
②电流表G2(0~100mA,内阻r2=1Ω)
③定值电阻R1(R1=150Ω)
④定值电阻R2(R2=15Ω)
⑤滑动变阻器R(0~5Ω)
⑥干电池(1.5V,内阻不计)
⑦开关S及导线若干