求大神帮做电路基础题!

可以直接用节点电压法,或者网孔电流法列方程求解,只是节点、网孔较多,解方程组麻烦。如图,我先用戴维南定理分两部分化简：(1) 用网孔电流法,左边网孔电流就是 1A 。9 * I1 - 3 * 1 = 2I1 = 5/9 A4 * I2 + 2 * 1 = 2I2 = 0 AUab = 6 * 5/9 = 10/3 ARab = 3//6 + 2//2 = 3 Ω(2) 并联分流。I1 = 7 * 9/14 = 4。5 AI2 = 7 * 5/14 = 2。5 AUab = 3 * 2。5 - 4 * 4。5 = - 10。5 VRab = 7//7 = 3。5 Ω(3) 合并：I = (10/3 + 10。5) / (3+3。5) = 2。128 AUab = 10/3 - 3 * 2。128 = -3。051 V