電路第3章部分習題選解

1、37題37圖所示電路中，，，，，1210RR???34R??458RR???62R??320VSu?，用支路電流法求解電流。640VSu?5i解由題中知道，獨立回路數(shù)為由KCL列方程：4n?6b?16413lbn???????對結點①1260iii???對結點②2340iii????對結點③4660iii????由KVL列方程：對回路Ⅰ642281040iii????對回路Ⅱ1231010420iii????對回路Ⅲ45488203ii

2、i???聯(lián)立求得0.956A5i??38用網(wǎng)孔電流法求解題37圖中電流。5i解可設三個網(wǎng)孔電流為、、，方向如題37圖所示。列出網(wǎng)孔方程為11i2li3li246122436211232333413234533()()()lllslllslllsRRRiRiRiuRiRRRiRiuRiRiRRRiu????????????????????????12312312320108401024420842020llllllllliiiiiiiii

3、??????????????????行列式解方程組為2010820104010244102420488084208420?????????????????所以351348800.956A5104ii????????311用回路電流法求解題311圖所示電路中的電流I。解由題已知，1I1Al?其余兩回路方程為????123123555303030203020305llllllIIIIII?????????????????代人整理得23223

4、34030352A3050151.5AllllllIIIII??????????????所以2321.50.5AllIII?????1R2R3R4R5R6R????3Su6Su①②③1i2i3i4i5i6iⅠⅡⅢ題3－7圖題311圖解（a）由題意可列出方程1212111()4102322111310112226nnnnuuuu??????????????????????????????12120.70.560.5510nnnnuuuu?

5、????????318列出題318圖（a）（b）所示電路的結點電壓方程。解（a）由題意電路結點電壓方程為1231231231142(111)(1)2221211112(1)(1)3222221114(1)32221nnnnnnnnnuuuuuuuuu??????????????????????????????????整理方程得到1231231223.51.571.520.520.527nnnnnnnnnuuuuuuuuu????????