1、电源AUR3I2I34A10V5AFigure 1.31.3(支路电流法)Consider the circuit of Figure 1.3 where R1=R2=1W and R3=2W. Find the three currents, I1, I2, I3.(Answer:)1.4 (电源模型的等效互换法)Use source transformations to find the voltage U across the 1-mA current source for the circuit shown in Figure 1.4. (Answer: U = 3 V)-600 14
2、00 3000 1 mA6 mA1.4 VFigure 1.41.5 (结点电位法) 如图1.5所示电路,用结点电位法求电流I1I4。2A15 10 20 5 V1V2V3图1.5 习题1.5的图I4图1.6 习题1.6的图R4USIS1.6 (叠加原理)用叠加原理计算图1.6中电阻R2中的电流I2。已知,。1A)1.7 (叠加原理)图1.7所示电路,已知:U1=0时,I=10mA,当U1= -10V时,I=-80mA。求U1=5V时,I是多少mA。55mA)图1.7 习题1.7的图IU1RU2U31.8 (戴维宁定理)Using Thevenins theorem, find the cur
3、rent I through the 24V voltage source for the circuit shown in Figure 1.8.(Answer: I=10A)24V1 4 5 2 7 Figure 1.81.9(戴维宁定理) A resistor, R, was connected to a circuit box as shown in Figure 1.9. The voltage, U, was measured. The resistance was changed, and the voltage was measured again. The results a
4、re shown in the table. Determine the Thvenin equivalent of the circuit within the box and predict the voltage, U, when R = 8 kW.(Answer:, ;当时)CircuitR U2k 4V4k 6VFigure 1.9图1.10 习题1.10的图R5+12V 24V+6V1.10 (戴维宁定理,结点电位法)图1.10所示电路,已知,。用戴维宁定理和结点电位法两种方法求电流I3。 0.8mA)1.11 (诺顿定理)求图1.11虚线框内电路的诺顿等效电路,并求使I=2A的R
5、L之值。2 )图1.11 习题1.11的图5VRL12V12 1.12(戴维宁定理,最大功率传输原理)图1.12所示电路,。求能获得最大功率的R为多少k ?R上获得的最大功率是多少mW?5k ,5mW)图1.12 习题1.12的图UR1.13(电阻网络的Y- 转换,戴维宁定理)用戴维宁定理求图1.13电路中的电流I。图中电阻值的单位为W。2A)图1.13 习题1.13的图26V10306090150.2A图1.14 习题1.14的图36V4V24 3 6 1.14 (解题方法任选)如图1.14所示电路,当恒流源IS为何值时,它两端的电压US0。-1.5A)1.15 (直流受控源,压控电流源)
6、Determine the node voltage Vb for the circuit of Figure 1.15.(Answer: Vb = 18 V)0.02Ua200 UaVb9 V100 Figure 1.151.16 (直流受控源,流控电压源) Determine the node voltage Va for the circuit of Figure 1.16. (Answer: Va = 10 V)1.17 (直流受控源,流控电流源,最大功率传输原理)Find the maximum power to the load RL if the maximum power tr
7、ansfer condition is met for the circuit of Figure 1.17. (Answer: PLmax = 0.75 W)Figure 1.164IaIaVa2 A6 2 W3 W0.9 A16 Vix10 ixFigure 1.17第2章正弦交流电路习题(18题)清华大学电机系电工学教研室 唐庆玉编2008.1.202.1 (正弦交流电路基本概念)已知电流,。求出各电流的频率,有效值,初相位,并在同一坐标中上画出i1、i2的相量,比较它们相位领先与落后的关系。2.2(正弦交流电路基本概念)将下列各相量所对应的瞬时值函数式写出来():,,2.3 (纯电容电
8、路,纯电感电路)如图2.3所示各电路,已知,测得。写出i的表达式,并求电容C或电感L的值。(a) 200mF;(b) 2H)(a)uiC图2.3 习题2.3的图(b)L2.4 (RC串联电路)图2.4所示RC串联电路,已知:,。求电流i,电压uR和uC,uR和uC与电压u的相位差。画出电压、电流的相量图。图2.5 习题2.5的图,uRuC图2.4 习题2.4的图2.5 (RL串联电路)已知某RL串联电路如图2.5所示,已知电流,有功功率P50W,无功功率Q50var。求:(1)电源电压u;(2)电路参数R、L。, R=50 ,L=0.05H)Z1Z2图2.62.6 (复杂交流电路,电源模型的等
9、效互换)图2.6所示电路,求电流、和电流源两端的电压及电流源的功率PS,并确定电流源在电路中的作用(是电源还是负载)。,。, ,)图2.72.7 (功率因数提高)如图2.7所示电路,已知,。(1)计算该电路的电流、电路的有功功率P及功率因数;(2)欲使电路的提高到1,需并联多大的电容C。并联电容后,电流I的值为多少,电路的有功功率P是否有变?,)Figure 2.88W2.4H2H0.1 F5sin5t V5cos5t Auabab_2.8 (复杂交流电路, 戴维宁定理) Using Thevenins theorem, Find the voltage uab between a and b
10、 for the circuit of Figure 2.8. (Answer:图2.9 习题2.9的图j2k 1k j3.6k j6k 3k 2.9 (复杂交流电路,结点电位法)如图2.9所示电路,已知:,。用结点电位法求1kW电阻两端的电压,并求虚线部分电路的平均功率、无功功率和视在功率。图2.11 习题2.11的图uL图2.10 习题2.10的图iCiLiRi12.10 (复杂交流电路,相量图)如图2.10所示电路,已知,电路的有功功率。求电路参数R、L、C。10 ,8.66mH,57.7 F)2.11 (串联谐振)图2.11所示电路,。该电路的电容C为多少时,电路产生串联谐振。谐振时电
11、流I0及电压UL是多大?该电路的Q值是多少?通频带BW是多大?2.12 (串联谐振)如图2.12所示电路中,已知,。求网络内的等效串联电路的元件参数值。5 ,2.5mF)图2.13 习题2.13的图图2.12 习题2.12的图网络2.13 (并联谐振)如图2.13所示电路,求谐振频率,谐振时的阻抗、,并画出电压和电流的相量图。,)2.14 (谐振电路)如图2.14所示电路,已知,当时电路发生谐振,此时。求R1和L的值。,)2.15 (谐振电路)如图2.15所示电路,当、时u与i同相位,而且。求电路参数R、L、C的值。图2.14 习题2.14的图c图2.15 习题2.15的图图2.16 习题2.16的图uo800 4000 Figure 2.172.16 (一阶低通滤波器)如图2.16所示电路,已知。画出幅频特性波特图,说明电路是高通还是低通网络,并求3dB频率。2.