代入元件VCR,得 IR tu tr+r-u=0 R1=19+us2=4V R,+R、+R 10V R,=2 R3=39 P u=-1A R R R u u I S S 1 1 2 3 1 2 = + + − = PuS1 = −uS1 I = −10W PvS2 = vS2 I = 4W 0 1 2 2 3 1 IR + uS + IR + IR −uS = 代入元件VCR，得 R1=1 + uS2=4V - I - R3=3 + uS1=10V R2= 2   