《电路分析》谭永霞西南交通大学课后习题及其答案
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《电路分析基础》各章习题参考答案第1章习题参考答案1-1 (1) SOW; (2) 300 V、25V,200V、75V; (3) R=12.50, R3=1000, R4=37.5021-2 V =8.S V, V =8.S V, V =0.S V, V =-12V, V =-19V, V =21.S V U =8V, U =12.5,A mB D 'AB B CU =-27.S VDA1-3 Li=204 V, E=205 V1-4 (1) V A=lOO V ,V=99V ,V c=97V ,V0=7V ,V E=S V ,V F=l V ,U A F=99V ,U c E=92V ,U8E=94V,8U BF=98V, u cA=-3 V; (2) V c=90V, V B=92V, V A=93V, V E=-2V, V F=-6V, V G=-7V, U A F=99V, u c E=92V, U B E=94V, U BF=98V, U C A =-3 V1-5 R=806.70, 1=0.27A1-6 1=4A ,11 =llA ,l2=19A1-7 (a) U=6V, (b) U=24 V, (c) R=SO, (d) 1=23.SA1-8 (1) i6=-1A; (2) u4=10V ,u6=3 V; (3) Pl =-2W发出,P2=6W吸收,P3=16W吸收,P4=-lOW发出,PS=-7W发出,PG=-3W发出1-9 l=lA, U5=134V, R=7.801-10 S断开:UAB=-4.SV, UA0=-12V, UB0=-7.2V; S闭合:12 V, 12 V, 0 V1-12 UAB=llV / 12=0.SA / 13=4.SA / R3=2.401-13 R1 =19.88k0, R2=20 kO1-14 RPl=11.110, RP2=1000第2章习题参考答案2-1 2.40, SA2-2 (1) 4V ,2V ,1 V; (2) 40mA ,20mA ,lOmA 2-3 1.50 ,2A ,1/3A2-4 60 I 3602-5 2A, lA2-6 lA2-7 2A2-8 lOA2-9 l1=1.4A, l2=1.6A, l3=0.2A2-10 11=OA I l2=-3A I p l =OW I P2=-l8W2-11 11 =-lA, l2=-2A I E3=10V2-12 11=6A, l2=-3A I l3=3A2-13 11 =2A, l2=1A ,l3=1A ,14 =2A, l5=1A2-14 URL =30V I 11=2.SA I l2=-35A I I L =7.SA2-15 U ab=6V, 11=1.SA, 12=-lA, 13=0.SA2-16 11 =6A, l2=-3A I l3=3A2-17 1=4/SA, l2=-3/4A ,l3=2A ,14=31/20A ,l5=-11/4A12-18 1=0.SA I l2=-0.25A12-19 l=1A32-20 1=-lA52-21 (1) l=0A, U ab=O V; (2) l5=1A, U ab=llV。
《电路分析基础》课程练习题及答案电路分析基础第一章一、1、电路如图所示,其中电流I 1为答( A ) A 0.6 AB. 0.4 AC. 3.6 AD. 2.4 A3Ω6Ω2、电路如图示, U ab 应为答 ( C )A. 0 VB. -16 VC. 0 VD. 4 V3、电路如图所示, 若R 、U S 、I S 均大于零,, 则电路的功率情况为答( B ) A. 电阻吸收功率, 电压源与电流源供出功率 B. 电阻与电流源吸收功率, 电压源供出功率 C. 电阻与电压源吸收功率, 电流源供出功率 D. 电阻吸收功率,供出功率无法确定UI S二、 1、图示电路中, 欲使支路电压之比U U 122=,试确定电流源I S 之值。
I SU解:I S由KCL 定律得:22328222U U U ++=U 248=V由KCL 定律得:0422=++U I U S1160-=S I A 或-5.46 A 2、用叠加定理求解图示电路中支路电流I ,可得:2 A 电流源单独作用时,I '=2/3A;4 A 电流源单独作用时, I "=-2A, 则两电源共同作用时I =-4/3A 。
3、图示电路ab端的戴维南等效电阻Ro = 4 Ω;开路电压Uoc=22 V。
b2解:U=2*1=2 I=U+3U=8A Uab=U+2*I+4=22V Ro=4Ω第二章一、1、图示电路中,7 V电压源吸收功率为答( C )A. 14 WB. -7 WC. -14 WD. 7 W2、图示电路在t=0时开关闭合,t≥0时u tC()为答(D )A. ---1001100(e)Vt B. (e)V-+-505050tC. --100100e V tD. ---501100(e )V tu C3、图示桥式电路中,已知t U u ωcos m s =,欲使图中u =0,应满足的条件为答( A )A.C L R R =21 B.LC R R 221ω=C. CR L R ωω21=D. CR L R ωω12=2u二、 1、试用叠加定理求图示电路中的电压U 。
第2章2.4 (a ) 10.27d m I I =;10.48m I I =(b )电流平均值:()2412sin 10.542md m m II I td t Iππωωππ⎛⎫==+≈ ⎪ ⎪⎝⎭⎰电流有效值:()()2241131sin 0.6784m mm I I t d t I I πππωωππ⎛⎫==+≈ ⎪⎝⎭⎰(c )30.25d m I I =;30.5m I I =2.5 188.2A d I =;2126.6A d I =;378.5A d I =1327.1A m I =;2232.9A m I =;3314A m I =解:在不同的电流情况下,晶闸管允许通过的电流有效值相等,即:123() 1.57100157A 2T av I I I I π====⨯=波形系数为:2220.67 1.240.54mf d mI I k I I ==≈100A 的晶闸管能输出的平均电流为:222157126.6A 1.24d f I I k ==≈相应的电流最大值为:22232.9A 0.67m I I =≈第3章3.4 59α=︒ , 121θ=︒, 37.4A I =/23.8A T f I I k == 考虑2倍裕量,选取 50Tav I A = 最大正反向电压=311V 考虑2倍裕量,选取 700V T U =3。
5 1) 59θ=︒;35.73A T av I =; 最大正反向电压为311V ;12.34 kVA S = ; cos 0.31ϕ=2) 129.75θ=︒;22.85 A Tav I =;最大正反向电压为91。
91V;2.33 kVA S =;cos 0.66ϕ=3。
6 1) dT 5.14A I =; dDz 7.19A I =; 7.96A T I =; 9.42A Dz I =2) dT 3.3A I =; dDz 6.6A I =; 5.72A T I =; 8.09A Dz I =3)只要0α>,dDz dT I I >,0α=,dDz dT I I =3.7 答: d 2 12sin d()171.6V U U t t ααωωπ+==π⎰ /d d I U R ==85.8A 22 1d()d d I I t I ααωπ+==π⎰=85.8A 2T 1d()/2d d I I t I ααωπ+==2π⎰=60.68A 57.168.60/==f T Tav k I I =38.65A 考虑2倍裕量,取晶闸管额定电流 100A 最大正反向电压22U =311V考虑2倍裕量,选取晶闸管额定电压700V3.11 d U =64。
《电路分析基础》各章习题参考答案第1章习题参考答案1-1 (1) 50W;(2) 300 V、25V,200V、75 V;(3) R2=12.5Ω,R3=100Ω,R4=37.5Ω1-2 V A=8.5V,V m=6.5V,V B=0.5V,V C=−12V,V D=−19V,V p=−21.5V,U AB=8V,U BC=12.5,U DA=−27.5V1-3 电源(产生功率):A、B元件;负载(吸收功率):C、D元件;电路满足功率平衡条件。
1-4 (1) V A=100V,V B=99V,V C=97V,V D=7V,V E=5V,V F=1V,U AF=99V,U CE=92V,U BE=94V,U BF=98V,U CA=−3 V;(2) V C=90V,V B=92V,V A=93V,V E=−2V,V F=−6V,V G=−7V,U AF=99V,U CE=92V,U BE=94V,U BF=98V,U CA=−3 V1-5 I≈0.18A ,6度,2.7元1-6 I=4A,I1=11A,I2=19A1-7 (a) U=6V,(b) U=24 V,(c) R=5Ω,(d) I=23.5A1-8 (1) i6=−1A;(2) u4=10V,u6=3 V;(3) P1=−2W发出,P2 =6W吸收,P3 =16W吸收,P4=−10W发出,P5=−7W发出,P6=−3W发出1-9 I=1A,U S=134V,R≈7.8Ω1-10 S断开:U AB=−4.8V,U AO=−12V,U BO=−7.2V;S闭合:U AB=−12V,U AO=−12V,U BO=0V 1-11 支路3,节点2,网孔2,回路31-12 节点电流方程:(A) I1 +I3−I6=0,(B)I6−I5−I7=0,(C)I5 +I4−I3=0回路电压方程:①I6 R6+ U S5 +I5 R5−U S3 +I3 R3=0,②−I5 R5−U S5+ I7R7−U S4=0,③−I3 R3+ U S3 + U S4 + I1 R2+ I1 R1=01-13 U AB=11V,I2=0.5A,I3=4.5A,R3≈2.4Ω1-14 V A=60V,V C=140V,V D=90V,U AC=−80V,U AD=−30V,U CD=50V1-15I1=−2A,I2=3A,I3=−5A,I4=7A,I5=2A第2章习题参考答案2-1 2.4 Ω,5 A2-2 (1) 4 V,2 V,1 V;(2) 40 mA,20 mA,10 mA2-3 1.5 Ω,2 A,1/3 A2-4 6 Ω,36 Ω2-5 2 A,1 A2-6 1 A2-7 2 A2-8 1 A2-9 I1 = −1.4 A,I2 = 1.6 A,I3 = 0.2 A2-10 I1 = 0 A,I2 = −3 A,P1 = 0 W,P2 = −18 W2-11 I1 = −1 mA,I2 = −2 mA,E3 = 10 V2-12 I1 = 6 A,I2 = −3 A,I3 = 3 A2-13 I1 =2 A,I2 = 1A,I3 = 1 A,I4 =2 A,I5 = 1 A2-14 V a = 12 V ,I1 = −1 A,I2 = 2 A2-15 V a = 6 V,I1 = 1.5 A,I2 = −1 A,I3 = 0.5 A2-16 V a = 15 V,I1 = −1 A,I2 = 2 A,I3 = 3 A2-17 I1 = −1 A,I2 = 2 A2-18 I1 = 1.5 A,I2 = −1 A,I3 = 0.5 A2-19 I1 = 0.8 A,I2 = −0.75 A,I3 = 2 A,I4 = −2.75 A,I5 = 1.55 A2-20 I3 = 0.5 A2-21 U0 = 2 V,R0 = 4 Ω,I0 = 0.1 A2-22 I5 = −1 A2-23 (1) I5 = 0 A,U ab = 0 V;(2) I5 = 1 A,U ab = 11 V2-24 I L = 2 A2-25 I S =11 A,R0 = 2 Ω2-26 18 Ω,−2 Ω,12 Ω2-27 U=5 V2-28 I =1 A2-29 U=5 V2-30 I =1 A2-31 10 V,180 Ω2-32 U0 = 9 V,R0 = 6 Ω,U=15 V第3章习题参考答案3-1 50Hz,314rad/s,0.02s,141V,100V,120°3-2 200V,141.4V3-3 u=14.1sin (314t−60°) V3-4 (1) ψu1−ψu=120°;(2) ψ1=−90°,ψ2=−210°,ψu1−ψu2=120°(不变)3-5 (1)150290VU=∠︒,25020VU=︒;(2) u3ωt+45°)V,u4ωt+135°)V3-6 (1) i1=14.1 sin (ωt+72°)A;(2) u2=300 sin (ωt-60°)V3-7 错误:(1) ,(3),(4),(5)3-8 (1) R;(2) L;(3) C;(4) R3-9 i=2.82 sin (10t−30°) A,Q≈40 var3-10 u=44.9sin (314t−135°) V,Q=3.18 var3-11 (1) I=20A;(2) P=4.4kW3-12 (1)I≈1.4A, 1.430AI≈∠-︒;(3)Q≈308 var,P=0W;(4) i≈0.98 sin (628t−30°) A3-13 (1)I=9.67A,9.67150AI=∠︒,i=13.7 sin (314t+150°) A;(3)Q=2127.4 var,P=0W;(4)I C=0A3-14 (1)C =20.3μF ;(2) I L =0.25A ,I C =16A第4章 习题参考答案4-1 (a) 536.87Z =∠︒Ω,0.236.87S Y =∠-︒;(b) 45Z =-︒Ω,45S Y =︒ 4-2 Y =(0.06-j0.08) S ,R ≈16.67 Ω,X L =12.5 Ω,L ≈0.04 H 4-3 R 600V U =∠︒,L 8090V U =∠︒,S 10053.13V U =∠︒ 4-4 2036.87I =∠-︒4-545Z =︒Ω,10A I =∠︒,R 1000V U =∠︒,L 12590V U =∠︒,C 2590V U =∠-︒ 4-645S Y =︒,420V U =∠︒,R 20A I =∠︒,L 0.2290A I =∠-︒,C 1.2290A I =∠︒4-7 10245A I =∠︒,S 10090V U =∠︒ 4-8 (a) 30 V ;(b) 2.24 A 4-9 (a) 10 V ;(b) 10 A 4-10 (a) 10 V ;(b) 10 V 4-11 U =14.1 V4-12 U L1 =15 V ,U C2 =8 V ,U S =15.65 V4-13 U X1 =100 V ,U 2 =600 V ,X 1=10 Ω,X 2=20 Ω,X 3=30 Ω4-14 45Z =︒Ω,245A I =∠-︒,120A I =∠︒,2290A I =∠-︒,ab 0V U =4-15 (1)A I =,RC Z =,Z =Ω;(2)10R =Ω,C 10X =Ω 4-16 P = 774.4 W ,Q = 580.8 var ,S = 968 V·A 4-17 I 1 = 5 A ,I 2 = 4 A4-18 I 1 = 1 A ,I 2 = 2 A ,526.565A I =∠︒,26.565V A 44.72S =∠-︒⋅4-19 10Z =Ω,190A I =∠︒,R252135V U =∠︒,10W P = 4-20 ω0 =5×106 rad/s ,ρ = 1000 Ω,Q = 100,I = 2 mA ,U R =20 mV ,U L = U C = 2 V 4-21 ω0 =104 rad/s ,ρ = 100 Ω,Q = 100,U = 10 V ,I R = 1 mA ,I L = I C = 100 mA 4-22 L 1 = 1 H ,L 2 ≈ 0.33 H第5章 习题参考答案5-3 M = 35.5 mH5-4 ω01 =1000 rad/s ,ω02 =2236 rad/s 5-5 Z 1 = j31.4 Ω,Z 2 = j6.28 Ω 5-6 Z r = 3+7.5 Ω 5-7 M = 130 mH 5-8 2245A I =∠︒ 5-9 U 1 = 44.8 V5-10 M 12 = 20 mH ,I 1 = 4 A 5-11 U 2 = 220 V ,I 1 = 4 A 5-12 n = 1.95-13 N 2 = 254匝,N 3 = 72匝 5-14 n = 10,P 2 = 31.25 mW第6章 习题参考答案6-1 (1) A 相灯泡电压为零,B 、C 相各位为220V6-3 I L = I p = 4.4 A ,U p = 220 V ,U L = 380 V ,P = 2.3 kW 6-4 (2) I p = 7.62 A ,I L = 13.2 A6-5 A 、C 相各为2.2A ,B 相为3.8A 6-6 U L = 404 V6-7 A N 20247U ''=∠-︒V6-8 cos φ = 0.961,Q = 5.75 kvar 6-9 33.428.4Z =∠︒Ω6-10 (1) I p = 11.26 A ,Z = 19.53∠42.3° Ω; (2) I p = I l = 11.26 A ,P = 5.5 kW 6-11 U l = 391 V6-12 A t 53.13)A i ω=-︒B t 173.13)A i ω=-︒C t 66.87)A i ω=+︒6-13 U V = 160 V6-14 (1) 负载以三角形方式接入三相电源(2) AB 3.8215A I =-︒,BC 3.82135A I =-︒,CA 3.82105A I =︒A 3.8645A I =∠-︒,B 3.86165A I =∠-︒,C 3.8675A I =∠︒6-15 L = 110 mH ,C = 91.9 mF第7章 习题参考答案7-1 P = 240 W ,Q = 360 var 7-2 P = 10.84 W7-3 (1)() 4.7sin(100)3sin3A i t t t ωω=+︒+ (2) I ≈3.94 A ,U ≈58.84 V ,P ≈93.02 W7-4 m12π()sin(arctan )V 2MU L u t t zRωωω=+-,z =7-5 直流电源中有交流,交流电源中无直流7-6 U 1=54.3 V ,R = 1 Ω,L = 11.4 mH ;约为8%,(L ’ = 12.33 mH )7-7 使总阻抗或总导纳为实数(虚部为0)的条件为12X R R R ==7-8 19.39μF C =,275.13μF C = 7-9 L 1 = 1 H ,L 2 = 66.7 mH 7-10 C 1 = 10 μF ,C 2 = 1.25 μF第8章 习题参考答案8-6 i L (0+)=1.5mA ,u L (0+)=−15V8-7 i 1(0+)=4A ,i 2(0+)=1A ,u L (0+)=2V ,i 1(∞)=3A ,i 2(∞)=0,u L (∞)=0 8-8 i 1(0+)=75mA ,i 2(0+)=75mA ,i 3(0+)=0,u L1(0+)=0,u L2(0+)=2.25V8-9 6110C ()2e Ati t -⨯= 8-10 4L ()6e V t u t -=8-11 6110C ()10(1e )V t u t -⨯=-,6110C ()5e A t i t -⨯= *8-12 500C ()115e sin(86660)V t u t -=+︒ 8-13 10L ()12e V t u t -=,10L ()2(1e )A t i t -=- 8-14 21R S ()eV t R Cu t U -=-,3R S (3)e V u U τ-=-8-15 (1) τ=0.1s ,(2) 10C ()10e V t u t -=,(3) t =0.1s 8-16 510C ()109e V t u t -=-8-17 10L ()5e A t i t -=8-18 (a)00()1()1(2)f t t t t t =---;(b)00000()1()1()[1()1(2)]1()21()1(2)f t t t t t t t t t t t t t =------=-⨯-+- 8-19 0.50.5(1)C ()[5(1e )1()5(1e )1(-1)]V t t u t t t ---=--- 8-20 u o 为三角波,峰值为±0.05V*8-21 临界阻尼R ,欠阻尼R ,过阻尼R *8-22 12666L ()[(1e )1()(1e)1(1)2(1e)1(2)]t t ti t t t t -----=-+-----。