只求一个未知数的题目适合用戴维南定理:
如图,网孔电流法,口算即可,1Ω 是公共电阻。
Uab = 3 * 2 + (3 - 1) * 1 - 1 * 2 = 6 V
Rab = 2 + 1 + 2 = 5 Ω
I = 6 / (5 + 3) = 0.75 A
http://wenku.baidu.com/view/1a26938d8762caaedd33d4bc.html
叠加原理步骤多,容易错,尽量少用:
I1 = 3 * 3 / 8 = 9/8 A
I2 = - 1 * 3/8 = - 3/8 A
合并:
I = I1 + I2 = 0.75 A