?Ri?R5i2?(R3?R4?R5)i3?0 41
23
24、用回路电流法求解电流 i. 选网孔为独立回路：
i?i?iRS + US
_ R1 iR4 i2 R5 ii3 R2 R3
解：只让一个回路电流经过R5支路
(RS?R1?R4)i1?R1i2?(R1?R4)i3?US?R1i1?(R1?R2?R5)i2?(R1?R2)i3?0?(R1?R4)i1?(R1?R2)i2?(R1?R2?R3?R4)i3?0i?i2 25、
RS + US
_ R1 iR4 iR2 5U _ + + R3 iU= _
解： S14 111
413
33
26、列回路电流方程
(R?R?R)i1?R1i2?R4i3?US?Ri?(R?R2)i2?5UU?Ri?Ri?(R?R4)i3??5UU1 _ + R1 + R2 _ 2 1 gU1 iS R3 _ + 3 R5 R4 4 _ + U1
解：选网孔为独立回路
3133 1
23 22 3134
53543
(R?R)i?Ri??U2Ri?U?U?Ri?(R?R?R5)i3?R5i4?0?Ri?Ri?U?? U1
i1?i2?iSi4?i2?gU1U1??R1i1
27、试列写电路的结点电压方程
1 GS + 2 G1 G3 G4 3 G2 Us
_ G5
(G1+G2+GS)U1-G1U2－GsU3=GSUS -G1U1+(G1 +G3 + G4)U2-G4U3 =0 －GSU1-G4U2+(G4+G5+GS)U3 =－USGS
28、列写电路的结点电压方程
1 R2 + uR2 _ iS R1 2
R3 gmuR2
① 先把受控源当作独立源列方程；
111(?)un1?un2?iS1R1R2R1111?un1?(?)un2??gmuR2?iS1R1R1R3uR2?un129、列写电路的结点电压方程
R5 1 + uS _ R3 + － r R2 + u3 iS _ 3 R1 R4 i gu3
2
un1?ri11111(??)un2?un1?un3??iS1?gu3R1R2R4R1R411111uS?un1?un2?(??)un3??gu3?R5R4R4R3R5R5
3n3
n22
32、求电压U和电流I
u??ui??uR
邱关源电路第五版课堂笔记
