A A ①E E 求解V4N,V4N2的节点方程 + AnI 1 A4N2 E 12 12 13 73+2求解 V V A N A N 3 1 4 2 , 的节点方程 1 ' 1 1 2 2 1 3 1 ' 4 2 2 ' ' 2 2 2 3 3 1 1 1 1 1 1 1 1 A l l l l A N A N A l l l i l i E Z Z Z Z Z V V E Z Z Z Z Z Z Z     + + −             =         − + +     +     + EA1 A1 Z l1 A3 A4 A2 Zl 2 Zl3 1 Z ' Z2 ' Zi N N1 N2 N3 A2 E' 