Sol ut i ons - Skule
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Name: ID number: ECE 212 Midterm October 20, 2016 6:10 - 8:00 Circle your lecture section: LEC101 (Phang) LEC102 (Taylor) LEC103 (Wong) Guidelines: • Please write your answer in the space beneath each question. Please write your answer in the space provided for each question. Show your work and use the back side of sheets as needed. • This exam is closed-note. • The formulae for delta-wye transformations are provided on the last page. • You may use a non-programmable calculator. • Only exams written in pen will be considered for regrades. Problem Score 1 /6 2 /4 3 /10 4 /4 5 /6 Total /30 1 Solutions
Transcript of Sol ut i ons - Skule
Name: ID number:
ECE 212Midterm
October 20, 20166:10 - 8:00
Circle your lecture section: LEC101 (Phang) LEC102 (Taylor) LEC103 (Wong)
Guidelines:
• Please write your answer in the space beneath each question. Please write your answerin the space provided for each question. Show your work and use the back side ofsheets as needed.
• This exam is closed-note.
• The formulae for delta-wye transformations are provided on the last page.
• You may use a non-programmable calculator.
• Only exams written in pen will be considered for regrades.
Problem Score
1 /62 /43 /104 /45 /6
Total /30
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Solutions
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1. The switch in the circuit below closes at time t = 0. Prior to t = 0, the circuit hassettled to its steady-state behavior with the switch open.
(a) (1 pts)Answer:Find v0(0
−).
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(b) (2 pts)Answer:Find the differential equation describing v0(t) for t ≥ 0.
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(c) (3 pts)Answer:Find v0(t) for t ≥ 0.
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Step-by-Step Approach
Solving differential equation from part b)
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2. (4 pts)Answer:If the total energy stored in the circuit is 80 mJ, what is the value of L?
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3. In this question, you will find I0 in the circuit below in two ways.
(a) (5 pts)Answer:Using the method of source transformation. Show each intermediate circuit inyour calculation with the values of the components clearly labelled.
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(b) (5 pts) Using nodal analysis. Your final answer should be the same as in part (a).
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4. (4 pts)Answer:Find the power supplied by the source. All resistors are 12 kΩ.
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5. Answer the following questions.
(a) (3 pts)Answer:For the circuit below, assuming the op-amp is ideal, determine the output voltagev0(t).
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(b) (3 pts)Answer:Determine the output voltage v0 again, but this time assume that the op-amphas a finite gain of A0 = 24 and that the equivalent circuit is as shown below.
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Delta-Wye Transformations
Ra =R1R2
R1 + R2 + R3
Rb =R2R3
R1 + R2 + R3
Rc =R1R3
R1 + R2 + R3
R1 =RaRb + RbRc + RaRc
Rb
R2 =RaRb + RbRc + RaRc
Rc
R3 =RaRb + RbRc + RaRc
Ra
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