用戴维南定理求下图电阻RL上的电流IL及恒流源的端电压。IL=0.33A

2024-11-22 10:41:47
推荐回答(1个)
回答1:

如图,断开RL,用节点电压法求出 Vc 电位:

(1/11 + 1/3 )* Vc = 16/11 + 1

Vc = 891/154 = 5.786 v

Va = Vc + 3 * (16 - Vc) / 11

     = 5.786 + 2.786

     = 8.572 V

Vb = 0 V         ;电流源内阻无穷大。

Uab = Va - Vb = 8.572 V

Rab = 20 + 8//6 = 23.43Ω

IL = Uab / (23.43 + 4)

    = 0.3125 A

求电流源电压:

R = 8 + 24//6 = 12.8 Ω

I = 16/12.8 = 1.25 A

I1 = 1.25 * 6 / 30 = 0.25 A

I2 = 1.25 * 24 / 30 = 1 A

Uab = 0.25 * 20 - 1 * 3 = 2 V

求 画出等效电路,求 Rab 太麻烦了,好像有一个公式可以求,忘了,等高手做吧。

U = Uab - 1 * Rab