电路理论基础习题答案第一章1-1. (a)、(b)吸收10W ；(c)、(d)发出10W. 1-2. –1A; –10V; –1A; – 4mW.1-3. –0.5A; –6V; –15e –tV; 1.75cos2t A; 3Ω; 1.8cos 22t W.1-4. u =104 i ; u = -104 i ; u =2000i ; u = -104 i ;1-8. 2μF; 4μC; 0; 4μJ. 1-9. 9.6V,0.192W, 1.152mJ; 16V , 0, 3.2mJ. 1-10. 1– e-106t A , t >0 取s .1-11. 3H, 6(1– t )2 J; 3mH, 6(1–1000 t ) 2 mJ;1-12. 0.4F, 0 .1-13. 供12W; 吸40W;吸2W; (2V)供26W, (5A)吸10W. 1-14. –40V , –1mA; –50V, –1mA; 50V , 1mA. 1-15. 0.5A,1W; 2A,4W; –1A, –2W; 1A,2W. 1-16. 10V ,50W;50V ,250W;–3V ,–15W;2V ,10W. 1-17. (a)2V;R 耗4/3W;U S : –2/3W, I S : 2W; (b) –3V; R 耗3W; U S : –2W, I S :5W; (c)2V ,–3V; R 耗4W;3W;U S :2W, I S :5W; 1-18. 24V , 发72W; 3A, 吸15W;24V 6电压源; 3A ↓电流源或5/3Ω电阻. 1-19. 0,U S /R L ,U S ;U S /R 1 ,U S /R 1 , –U S R f /R 1 . 1-20. 6A, 4A, 2A, 1A, 4A; 8V, –10V , 18V . 1-21. K 打开：(a)0, 0, 0; (b)10V, 0, 10V; (c)10V,10V ,0; K 闭合: (a)10V ,4V ,6V; (b)4V ,4V ,0; (c)4V ,0,4V; 1-22. 2V; 7V; 3.25V; 2V. 1-23. 10Ω.1-24. 14V .1-25. –2.333V , 1.333A; 0.4V , 0.8A. 1-26. 80V . 1-26（习题册）（a ）：12V;2A;-48W. (b):-6V;3A;-54W ※第二章2-1. 2.5Ω; 1.6R ; 8/3Ω; 0.5R ; 4Ω; 1.448Ω; . R /8; 1.5Ω; 1.269Ω; 40Ω; 14Ω. 2-2. W P 484＝低,W P 4484⨯=高. 2-3. 1.618Ω.2-4. 400V;363.6V;I A =.5A, 电流表及滑线电阻损坏. 2-6. 5k Ω. 2-7. 0.75Ω.2-8.R 1=38K Ω,R 2=10/3K Ω 2-9. 10/3A,1.2Ω;–5V ,3Ω; 8V ,4Ω; 0.5A,30/11Ω. 2-10. 1A,2Ω; 5V,2Ω; 2A; 2A; 2A,6Ω. 2-11. –75mA; –0.5A.2-12. 6Ω; 7.5Ω; 0; 2.1Ω. 2-13. 4Ω; 1.5Ω; 2k Ω. 2-14.1.6V ,-24V 2-15.(习题册) 2.5W 2-15. (a) 2A; (b) –2 A ↓, 吸20W. 2-16. 2-17. 3A. 2-18. 7.33V . 2-19. 85.76W. 2-20. 1V, 4W. 2-21. 64W.2-22.电压源发50W ，电流源发1050W 2-232-24. 7V, 3A; 8V ,1A. 2-25. 4V, 2.5V, 2V. 2-26.2Ω 2-27. 60V . 2-28. 4.5V. 2-29. –18V .2-29（习题册）:4W;48W2-30. 原构成无解的矛盾方程组; (改后)4V,10V . 2-312-32.2.5A2-33. 3.33 k ς, 50 k ς.2-34 加法运算 )(3210i i i u u u u ++-= 2-35. R 3 (R 1 +R 2 ) i S /R 1 . 2-36. 可证明 I L =－ u S /R 3 .2-37. –2 ; 4 .2-38 11/2 ※第三章3-1. 44V;–1+9=8V; 6+9=15V; sin t+0.2e–t V. 3-2. 155V.3-3. 190mA.3-4. 1.8倍.3-5. 左供52W, 右供78W.3-6. 1ς; 1A; 0.75A.3-7. 3A; 1.33mA; 1.5mA; 2/3A; 2A.3-8. 20V, –75.38V.3-8(习题册)：0.2Ω3-9(习题册)：2W3-9. –1A; 2A; 1A.3-10. 5V, 20ς; –2V, 4ς.3-12. 4.6ς.3-13. 2V; 0.5A.3-14. 10V, 5kς.3-15.3-16.22.5V3-17. 4/3ς, 75W; 4/3ς, 4.69W.3-18. 3ς, 529/12W.; 1ς, 2.25W.3-193-20. 50ς.3-21. 0.2A.3-22. 1A.3-23. 1.6V.3-24. 4A;3-25. 23.6V; 5A,10V.3-26.3-27 4V3-28. ※第四章4-1. 141.1V, 100V, 50Hz, 0.02s,0o, –120o; 120 o. 4-2. 7. o A, 1/–45 o A, 18.75/–40.9 o A.4-3. U, 7.75mA .4-4. 10/53.13A, 10/126.87o A, 10/–126.87o A, 10/–53.13o A；各瞬时表达式略。

4-5. 67.08V, 30V, 25V; 12V, 0, 12V, 0; 0, 0, 12V. 4-6. 7.07A; 10A, 50A.4-7. 173.2ς.4-8. 4ς, 1.5H.4-9.11V4-10. 5ς, 0.1F.4-11. 5A; 20/–53.13oς, 0.05/53.13o S. 4-124-13. 5ς, 0.0577F; 3ς, 29.33H;3ς,0.125F; 0ς,0.02F4-14.-Z4-15.4-16. 10A, 141V.4-17. 3.47ς, 53.2μF.4-18. .A)4.1081000cos(2316.0︒+t4-19. 26.3ς, 78.8mH, 34.6μF.4-20. 118.0V, 0.252μF.4-21. 0.751μF .4-22. 40.53pF.4-23.4-24. 10/0o A, 10/0o V, 200W,1; 20A, 0；5A.4-25. 21.26A,1800W,0.846; 10.2ς,2778W,0.926; 26.04μF.4-26. 495W, 0.375.4-27.4-28. 20 + j10ς, 2.5W, 0.894.4-29. 1.99ς,31.99ς或6.11ς, 11ς,–19.05ς.4-30. 30+j10=31.62/18.43o V, 300W, –300Var.4-31. )75cos(2︒+t A;2VA, j2V A,2V A,–j2V A,–4V A.4-31(习题册)：-0.5j.4-32. 2/–90o A; 13.3/11.9o V, 7.97–j2.16ς,3.16/63.4o V, 1+j1ς.4-33(习题册)：(1):I=1.5+2j;U1=75j (2)S=400V A;P=240W;Q=-320Var4-34. 5A, 11.09A, 10.83A, 1066W.4-35. )61(12ωωj--.4-36. 200/–150o mA.4-37. 10H.4-38. 5ς, 27.57mH, 367.75μF.4-39. 0.5ς, 0.5H; 0.25W.4-40. 1.86 + j0.56ς, 8.10W.4-41. 0.8 + j0.4ς, 0.125W4-42.4-43. 100ς, 0.667H, 0.167μF, 20..4-44. 10ς, 0.796mH, 3183pF; 50.4-45. 0.1μF; ;A5000cos22.0ti=.V)905000cos(2400︒+=tuL4-46. 0.02H, 50.4-47. 100.5pF, 0.091V.4-48. 25μF , 180V.4-49. 0.253μF , 0.760μF .4-50. 4.12A.4-51.4-52. 30.09(-65.8)A, 17.37(-35.8)A.4-53. 2850W;1425W 4-54.4.84ς4-55. 9077W;7942W4-56. (1) I A 不变，因对称时中线不起作用。

(2) 仍不变，因为S 闭合时各相负载电压未变，电流表所涉及的两个A 相负载也未变。

4-57. 38/–53.13o A, 38/–66.87o A, 33.59/75oA;64.41/–77.35o A; 9.09/–150.0o A; 67.68/95.29oA. 4-58. 190W, 380W. 4-59. 1kW. 4-60. 6.06A.4-61. 871.2W, 1161.6Var; 290.4W, –668.5Var. 4-62. P (a) =P 左 +P 右 ; Q (b ) =3P W .4-63. ; )3( , )3311Z Z E Z Z Z E A A ++ 可. 4-64. 0.1103H, 91.89μF. ※第五章5-1. ;V sin 5.0 ,V sin 2 ;V cos 25.0 ,V cos t t t t -.V 25.05.0 ,V 225.022t t t t e e e e ------5-2. 根据tit i u t i t i u d d 2d d d d d d 4211 211,+=+=绘出.5-3. .V )13.1432cos(215o-t5-4. (b)读数大。

5-5. V e t --5,V e t-5.10 5-6. 52.83mH. 5-7.5-8. 20mH, 2.2V, 4.4V, 4.4V , 44mA, 22mA, 66mA.5-9. 1.59/–12.7oA.5-10. 13.o .69/–61.3oV. 5-11. 1( . 5-12. j 0.75ς. 5-13.5-14. 50mH.5-15. 20μH, 2.5W, 250V.5-16. 4.06/–20.98o A , 0.406/–9.05o A , 8.903/–157.8oA . 5-17. 2kW, 3.2kW.5-18. 0.09W; 3, 0.25W. 5-19. 1.414A.5-20. U 2 /U 1 从3.356 降为0.0239. 5-21. 20 – j 15ς, 2.8125W.5-22. 80.0W, –20.0W, 100W.注意到P R 1= 20W ，P R 2= 60W ，可见：电源供给第2线圈共100W 的功率，其本身仅耗60W ，其余40W 经互感耦合至第1线圈，线圈1耗20W ，还剩20W 送还给电源(P 1=－20W) ⇒ P =100－20 = 80W 。