Ryerson University
Department of Electrical and Computer Engineering
Final Examination, EES512 Electric Circuits
Duration: 2hours and 50 minutes
December 2010
Student’s Name:…………………………………………………………………………...
Student Number:…………………………………..
Signature:…………………..
NOTES:
•
This is a closed book, and closed course note examination.
•
NO QUESTIONS to be asked. If doubt exists as to the interpretation of any
question, you are urged to submit with the answer, a clear statement of any logical
assumptions made.
•
There are 9 questions. Answer all questions. Marks for each question and its
parts are mentioned. Hand in this exam questionnaire with your solution booklet.
Question
Mark
Q1
10
Q2
10
Q3
10
Q4
5
Q5
10
Q6
10
Q7
10
Q8
10
Q9
15
Total
90
Mark obtained
1
Fig. 1: (Superposition/Nodal/Mesh/Source Transformation)
Q1: (Superposition): In the circuit shown above, find vo using Superposition technique.
A. We have two independent sources. Draw the two circuit configurations required for
superposition.
(2 marks)
B. Find vo1 due to the current source only only.
(3 marks)
C. Find vo2 due to the voltage source only.
(3 marks)
D. What is the total vo due to both independent sources?
(2 marks)
Q2: (Nodal): In the circuit shown above, find vo using Nodal technique. Select a reference
node.
A. Write the nodal equations for the non-reference nodes.
(3 marks)
B. Simplify the equations you wrote in part (A).
(2 marks)
C. Solve the simplified system in part (B). Provide numerical answers.
(2 marks)
D. Express vo in terms of node voltages and Ohm’s law. Provide numerical value for vo.
(3 marks)
Q3: (Mesh): In the circuit shown above, find vo using Mesh technique.
A. Write the mesh equations for two loops. Assign the loops anyhow you like.
(3 marks)
B. Simplify the equations you wrote in part (A).
(2 marks)
C. Solve the simplified system in part (B). Provide numerical answers.
(2 marks)
D. Express ix in terms of loop currents, and provide numerical values for vo.
(3 marks)
Q4: (Source Transformation): In the circuit shown above, find vo using source transformation.
A. Use source transformation at least once and create a simple circuit.
(3 marks)
B. Use either Voltage and/or Current divider or Ohm’s laws to get vo.
(2 marks)
2
Q5: (Maximum Power Transfer):
A. Calculate the value of R for maximum power transfer in Fig2.
(8 marks)
B. Determine the maximum power absorbed by R.
(2 marks)
Fig. 2: (Maximum Power Transfer)
Q6: (Wheatstone Bridge/Norton): In Fig. 3, find the Norton equivalent seen from terminals ab.
(10 marks)
Fig. 3: (Wheatstone Bridge/Norton)
Q7: (RC): The switch in Fig. 4 has been in position A for a long time. At t=0, the switch moves
from position A to B. The switch is a make-before-break type so that there is no interruption in
the inductor current. Find i(t) and v(t).
(10 marks)
Fig. 4: (RC Circuit with DC excitation)
3
Q8: (RL): Find i(t) in the circuit of Fig. 5.
(10 marks)
Fig. 5: (RL Circuit with DC excitation)
Q9: (Energy): For the circuit in Fig. 6, calculate the value of R that will make the energy stored
in the capacitor the same as that stored in the inductor under DC steady-state conditions.
(15 marks)
Fig. 6: (Energy)
4