电路概念与分析方法

1、会计学1电路概念与分析方法电路概念与分析方法2021-12-1022021-12-103电源电源: :2021-12-1042021-12-1052021-12-106+- -电压源元件（电压源元件（US）电流源元件（电流源元件（IS）电电 感感 元元 件件 （L）电电 容容 元元 件件 （C）电电 阻阻 元元 件（件（R）2021-12-1072021-12-1082021-12-1092021-12-10102021-12-10112021-12-1012关联参考方向关联参考方向非关联参考方向非关联参考方向I+-+-IUURRURIURI 2021-12-10136 32URI 6 32U

2、RI 2021-12-1014R2021-12-1015WPUIt2021-12-1016消耗能量，消耗能量，发出能量，发出能量，2021-12-101722/PUIRIUR WUItPt 2021-12-10182021-12-1019iu+-eL+-LddddieLtt ddLiueLt212WLi2021-12-10202021-12-1021+_够够qCu212WCudduiCt2021-12-10222021-12-1023121111.eqnCCCC12.eqnCCCC12.eqnLLLL1231111.eqLLLL电容串联：电容串联：电容并联：电容并联：电感串联：电感串联：电感并

3、联：电感并联：2021-12-10242021-12-10252021-12-10262021-12-1027 SSOUIR2021-12-1028 2021-12-10292021-12-10302021-12-1031S0UIIR2021-12-10322021-12-1033电流源的方向为电压源的负极到正极的方向。电流源的方向为电压源的负极到正极的方向。2021-12-10342021-12-1035SSS00UUIR 2021-12-10362021-12-10372021-12-1038nkSksnsssSequuuuuu1321补充：补充：2021-12-1039121nSsssn

4、skkiiiii等效电路等效电路82A1A222I23A2A21I 2021-12-1045U U0 0=1500I-100I+20=1400I+20=1500I-100I+20=1400I+202021-12-10522021-12-10542021-12-10552021-12-10562021-12-10572021-12-1058ABUCABBUCUAU+RB1RCRB2REIEIBUCCICUCE2021-12-1059解：解：绕行方向和各元件绕行方向和各元件上的电压如图所示。上的电压如图所示。对右侧回路由对右侧回路由KVL得得-U-UABAB-I-I2 2R R2 2+U+Us2s

5、2=0=0- -（-2-2）-20I-20I2 2+10=0+10=0得：得：I I2 2=0.6mA=0.6mA对左侧回路由对左侧回路由KVLKVL得得U Us1s1-I-I1 1R R1 1-I-I2 2R R2 2+U+Us2s2=0=06-10I6-10I1 1-0.6-0.620+10=020+10=0得：得：I I1 1=0.4mA=0.4mA2021-12-1062baI1I2U2+-R1R3R2+_I3#1#2#3U1123III 312III 1113322233121122UI RI RUI RI RUUI RI R baI1I2U2+-R1R3R2+_I3#1#2#3U1

6、2021-12-1064N=2、B=3bR1R2U2U1+-R3+_a3341 A1I ？1 +-3V4V1 1 +-5VI1I2I323456 A1I 1237 AIII 2021-12-10662021-12-10672021-12-1070例例1.6.12021-12-10712021-12-10722021-12-107311110nuvvu22220nuvvu33330nuvvu41313nnuvvuu51212nnuvvuu62323nnuvvuu111222333441355126623()()()nnnnnnnnniGuiG uiG uiG uuiG uuiG uu2021-1

7、2-1074整理后：整理后：111122133112112222332231132233333nnnsnnnsnnnsG uG uG uiG uG uG uiG uG uG ui写出一般形式：写出一般形式：14515243151256263416234632()()0()nnnsnnnnnnsGGG uG uG uiG uGGG uG uG uG uGGG ui 2021-12-10751111221(1)(1)112112222(1)(1)22(1)11(1)22(1)(1)(1)(1)(1).nnnn nSnnnn nSnnnnnnn nS nnG uG uGuiG uG uGuiGuGu

8、Gui自电导总为正，互电导总为负。自电导总为正，互电导总为负。流入该节点流入该节点的等效电流的等效电流源，流入取源，流入取+ +，流出取，流出取- -自自电电导导互互电电导导2021-12-1076例例3.8用节点电压法求电路中各电阻支路电流用节点电压法求电路中各电阻支路电流 解：解：参考节点和节点电压如图所示。设节点电压分别为参考节点和节点电压如图所示。设节点电压分别为u un1n1和和u un2n2，用观察法列出节点方程，用观察法列出节点方程 整理得：整理得：解得各节点电压为解得各节点电压为12(1 1)(1)5Annuu12(1)(12)10Annuu 1225Vnnuu12310Vnn

9、uu 11Vnu23Vnu 2021-12-1077（2）与电流源串联的电阻不写入方程中。）与电流源串联的电阻不写入方程中。2021-12-10782021-12-1079s1212UIIRR2112SRIIRR s2111S1212URIIIIRRRR1212SRIIRRs1S1212URIRRRRs22310A1A55UIRR S221 5V5VUI R 222 1A0.5A0.5AIII所所以以32S23510.5A55RIIRR S220.5 5V2.5VUR ISSS5V2.5V7.5VUUU2021-12-108422221111111111( ) PR IR IIR IR I2021-12-10852021-12-108612124020A2.5 A44UUIRR120122RRRRR s30330A2 A2 13UIRRs11260.646UIRRs23460.3128UIRR011420.6 60.3 81.2UR IR I 3