节点电压法 R 1+C122+G133 11 G2u,+ g22u2+G 2343 s22 G,,+G,l2+G 333 S33 5:45:353 1 1 3 2 2 3 3 3 3 3 2 1 1 2 2 2 2 3 3 2 2 1 1 1 1 2 2 1 3 3 1 1 s s s G u G u G u I G u G u G u I G u G u G u I + + = + + = + + = 节点电压法 1 2 3 4