University of Alexandria
Faculty of Engineering
Computer and Communication Engineering
Specialized Scientific Programs (SSP)
Course Name: Electrical Circuits II Course Code: CC 202
Lecturer: Dr. Bassem Mokhtar
Academic Year: Fourth Term 2015–2016 Semester: Spring 2016
Sheet One: AC Circuits Analysis – Review on Basic Concepts
1. Choose the correct answer for the following questions. Justify your choice.
a. If 𝑣1 = 30sin⁡(𝜔𝑡 + 10𝑜 ) and 𝑣1 = 20sin⁡(𝜔𝑡 + 50𝑜 ) which of these statements are true?
i. 𝑣1 ⁡𝑙𝑒𝑎𝑑𝑠⁡𝑣2
ii. 𝑣2 ⁡𝑙𝑒𝑎𝑑𝑠⁡𝑣1
iii. 𝑣2 ⁡𝑙𝑎𝑔𝑠⁡𝑣1
iv. 𝑣1 ⁡𝑎𝑛𝑑⁡𝑣2 ⁡𝑎𝑟𝑒⁡𝑖𝑛⁡𝑝ℎ𝑎𝑠𝑒
b. At what frequency will the output voltage 𝑣𝑜 (𝑡) in the figure be equal to the input voltage (𝑡) ?
i. 0 rad/s
ii. 1 rad/s
iii. 4 rad/s
iv. ∞ rad/s
v. None of the above
c. For the depicted circuit below, the Thevenin impedance at terminals a-b is:
i. 1 Ω
ii. 0.5 – j0.5 Ω
iii. 0.5 + j0.5 Ω
iv. 1+ j2 Ω
v. 1– j2 Ω
d. The average power absorbed by an inductor is zero.
i. True
ii. False
e. The Thevenin impedance of a network seen from the load terminals is 80 + j55 Ω. For maximum
power transfer, the load impedance must be:
i. – 80 + j55 Ω
ii. – 80 – j55 Ω
iii. 80 – j55 Ω
iv. 80 + j55 Ω
f. If the load impedance is 20 – j20 Ω, the power factor is
i. 0
ii. 1
iii. 0.7071
iv. None of the above
2. Transform the following sinusoid (4 cos 2t + 3 sin 2t) to phasor.
3. If the current through an inductor is . Prove that the voltage across such inductor can be represented
with this polar form 𝑉 = 𝑗𝜔𝐿𝐼
4. What value of 𝜔 will cause the forced response 𝑣𝑜 in the figure to be zero?
5. For the circuit shown in the figure, find 𝑍𝑒𝑞 and use that to find current I. Let 𝜔 = 10 rad/s.
6. Find Z in the circuit of the figure, given that 𝑉𝑜 = 8𝑒 𝑗0 V.
7. Obtain 𝑍𝑖𝑛 for the circuit in the following figure.
8. Find 𝑖𝑥 in the following circuit using nodal analysis.
9. Determine the current 𝐼𝑜 in the following circuit using mesh analysis.
10. In the circuit below, determine the mesh currents 𝑖1 𝑎𝑛𝑑⁡𝑖2 and Let 𝑣1 = 10 cos 4𝑡 V and
𝑣2 = 20⁡cos⁡(4𝑡 − 30𝑜 ) V.
11. Determine 𝑖𝑜 in the circuit using the superposition principle.
12. Use the concept of source transformation to find 𝑉𝑜 in the shown circuit.
13. Find the Thevenin equivalent circuit to the left of the terminals a and b.
14. Calculate the output impedance of the circuit shown below.
15. Obtain the Norton equivalent of the circuit depicted below at terminals a-b.
16. At terminals a-b, obtain Thevenin and Norton equivalent circuits for the network depicted in the
figure. Take 𝜔 = 10 rad/s.
∗
17. According to the figure, prove that the maximum average power transfer occurs when 𝑍𝐿 = 𝑍𝑇ℎ
18. Assuming that the load impedance is to be purely resistive, what load should be connected to
terminals a-b of the circuits in the figure below so that the maximum power is transferred to the
load?
19. Calculate the effective value of the current waveform in the figure and the average power
delivered to a 12 Ω resistor when the current runs through the resistor.