求大神帮做电路基础题!
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求大神帮做电路基础题!
如图
![](http://img.wesiedu.com/upload/7/18/7183f80580600b193aa177b1b0fa7c76.jpg)
如图
![](http://img.wesiedu.com/upload/7/18/7183f80580600b193aa177b1b0fa7c76.jpg)
![求大神帮做电路基础题!](/uploads/image/z/3003357-21-7.jpg?t=%E6%B1%82%E5%A4%A7%E7%A5%9E%E5%B8%AE%E5%81%9A%E7%94%B5%E8%B7%AF%E5%9F%BA%E7%A1%80%E9%A2%98%21)
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:
![](http://img.wesiedu.com/upload/f/d7/fd7870a6022e5661af24d211a5885509.jpg)
(1) 用网孔电流法,左边网孔电流就是 1A .
9 * I1 - 3 * 1 = 2
I1 = 5/9 A
4 * I2 + 2 * 1 = 2
I2 = 0 A
Uab = 6 * 5/9 = 10/3 A
Rab = 3//6 + 2//2 = 3 Ω
(2) 并联分流.
I1 = 7 * 9/14 = 4.5 A
I2 = 7 * 5/14 = 2.5 A
Uab = 3 * 2.5 - 4 * 4.5 = - 10.5 V
Rab = 7//7 = 3.5 Ω
(3) 合并:
![](http://img.wesiedu.com/upload/d/d8/dd8a63597493aed5865eabcb2757a7bc.jpg)
I = (10/3 + 10.5) / (3+3.5) = 2.128 A
Uab = 10/3 - 3 * 2.128 = -3.051 V
![](http://img.wesiedu.com/upload/f/d7/fd7870a6022e5661af24d211a5885509.jpg)
(1) 用网孔电流法,左边网孔电流就是 1A .
9 * I1 - 3 * 1 = 2
I1 = 5/9 A
4 * I2 + 2 * 1 = 2
I2 = 0 A
Uab = 6 * 5/9 = 10/3 A
Rab = 3//6 + 2//2 = 3 Ω
(2) 并联分流.
I1 = 7 * 9/14 = 4.5 A
I2 = 7 * 5/14 = 2.5 A
Uab = 3 * 2.5 - 4 * 4.5 = - 10.5 V
Rab = 7//7 = 3.5 Ω
(3) 合并:
![](http://img.wesiedu.com/upload/d/d8/dd8a63597493aed5865eabcb2757a7bc.jpg)
I = (10/3 + 10.5) / (3+3.5) = 2.128 A
Uab = 10/3 - 3 * 2.128 = -3.051 V