Problems and Solutions 不要用看的，要動手！ CHAPTER 5 Problems and Solutions 不要用看的，要動手！

Problem 1 a. Determine the currents I and IL for the network in Fig. 5 Problem 1 a. Determine the currents I and IL for the network in Fig.5.77. b. Find the power delivered to the resistor R2.

ZR1 ZR2 ZR2與ZL串聯成 Z’ ZL ZC ZC與Z’並聯成 Z”

ZR1 ZR2 ZR2與ZL串聯成 Z’ ZL ZC ZC與Z’並聯成 Z”

延伸問題 a. E與I的相位差？ b.從電壓源E往右看，由R1…XL所組成電路，是那一種特徵的電路？電感特徵？電容特徵？

Problem 2 a. Determine the vo1tage Vs for the network in Fig.5.78. b. Find the power delivered to R2.

ZL ZC ZR1 ZR2

ZL ZC ZR1 ZR2 另一條路…

延伸問題 求vs(t) ？

Problem 7 Determine the current I in Fig. 5 Problem 7 Determine the current I in Fig. 5.79 by first converting both voltage sources to current sources and then combining the parallel current sources.

將ZR1與ZC並聯起來Z’

利用Current divider rule

Problem 8 Convert the current source in Fig.5.80 to a voltage source and find the current I by combining the series voltage sources and using Ohm's law.

2kΩ

Problem 9 a. Determine the current through the inductor of Fig. 5.79 using mesh analysis. b. Using the results for part (a) find the voltage across the inductor.

Z1=2kΩ Z3=5kΩ∠-90° I1 I2 Z2=4kΩ∠90° Mesh 1 Mesh 2

跨越電感的電壓降

Problem 10 Determine the current I in Fig.5.81 using mesh analysis.

Z1=10Ω∠0° Z2=20Ω∠0° I1 I2 Z3=30Ω∠90° Z4=50Ω∠-90° Mesh 1 Mesh 2

Z1=10Ω∠0° Z2=20Ω∠0° I1 I2 Z3=30Ω∠90° Z4=50Ω∠-90°

Problem 11 Determine the current through resistor R2 in Fig 5.86.

I2 I1 I3 Mesh 1 Mesh 2 Mesh 3

解出

Problem 12 Determine the voltage across the resistor R2 in Fig 5.86.

Z3 Z1 Z2 Z6 Z5 Z4

Problem 13 a. Determine the nodal voltages for the network in Fig.5.82. b. Calculate the current through each impedance using the results for part (a).

V2 V1 NODE 1 NODE 2

Problem 14 Find the Thévenin equivalent circuit for the network to the left of the load ZL in Fig. 5.83.

ZTH、ETH

Problem 15 a. Determine ZL for maximum power to ZL in Fig. 5.83. b. Calculate the maximum power that can be delivered to ZL.

R + XL For max. power

Problem 16 a. Find the Thévenin equivalent circuit for the network to the left of XC= 50Ω in Fig. 5.81. b. If XC in Fig. 5.81 is replaced by a load ZL, determine R and X for the load so that the load will receive maximum power.

LOAD For max. power 由電阻與電容串聯而成， 電容的電抗（reactance）30Ω

Problem 17 a. Find the Thévenin equivalent circuit for the network to the left of ZL in Fig. 5.84. b. Determine ZL for maximum power to ZL. c. Calculate the maximum power to ZL.

For max. power 由電阻與電感串聯而成， 電感的電抗（reactance）9.17Ω

Problem 23 For the network in Fig. 5.88, determine: a. The current through each branch using Ohm's law. b. The total power dissipated (real power). c. The net reactive power. d. The total apparent power e. The network power factor.

a. b.

c. d. Total apparent power e. Power factor

Problem 24 For the system in Fig. 5.89, determine: a. PT b. QT c. ST d. I e. FP

a. Total power b. Net reactive power Lagging 電感性較強 c. Total apparent power

d. e. Power factor Lagging