MAE140 Linear Circuits Winter 09 Midterm Exam, Exams of Introduction to Sociology

Download MAE140 Linear Circuits Winter 09 Midterm Exam and more Exams Introduction to Sociology in PDF only on Docsity! MAE140 - Linear Circuits - Winter 09 Midterm, February 5 Instructions (i) This exam is open book. You may use whatever written materials you choose, including your class notes and textbook. You may use a hand calculator with no communication capabilities (ii) You have 70 minutes (iii) Do not forget to write your name, student number, and instructor A B C D i 1 i 2 i 3 3 A20 V 20 Ω 20Ω 10 Ω 20 Ω Figure 1: Circuit for questions 1-4. 1. Equivalent circuits Part I: [2 points] Turn off all the sources in the circuit of Figure 1 and find the equivalent resistance as seen from terminals C and D. Part II: [3 points] Find the Thévenin equivalent as seen from terminals C and D. Hint: If you want, you can use the result obtained in Part I Part III: [1 point] Find the power absorbed by a 9 Ω resistor that is connected to terminals C and D. 2. Nodal voltage analysis [6 points] Assuming that the node labeled D is the ground node (reference), formulate node-voltage equations for the circuit in Figure 1. Use the node labels provided in the figure and clearly indicate how you handle the presence of a voltage source, the final equations, and the unknowns they must be solved for. Do not modify the circuit or the labels. No need to solve any equations! 3. Mesh current analysis [6 points] Formulate mesh-current equations for the circuit in Figure 1. Use the mesh currents shown in the figure and clearly indicate how you handle the presence of a current source, the final equations, and the unknowns they must be solved for. Do not modify the circuit or the labels. Do not use any source transformation. No need to solve any equations! Hint: Use a supermesh 4. Bonus question [1 point] If you were allowed to use source transformations in the circuit of Figure 1, describe what would you do in order to avoid having to use a supermesh in Question 3? Do not write or solve any equations!