ECE 220 Basic Circuits Final Examinationmwm/classes/220/Exams/...Microsoft Word - final.docx Author...
Transcript of ECE 220 Basic Circuits Final Examinationmwm/classes/220/Exams/...Microsoft Word - final.docx Author...
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Color: Ivory
Closed book/notes, calculators allowed up to level of TI89, TI Inspire CAS, HP50.
Part I: 12 questions Part II: 12 questions Part II questions are worth twice as much as Part I questions. On the SCANTRON write and bubble-in your: 1. Name (Last, first) 2. Below your first name, bubble in the color of your exam paper (A=IVORY or B=GREEN). Show your UofA picture ID card when you turn in your exam. All work should be done on the examination paper. Allow for reasonable amounts of round off error, and carefully mark one choice for each problem on the SCANTRON answer sheet. All answer sheets and examinations will be collected after 2 hours. You will be asked to stop writing and hand in your papers/answer sheets. Failure to comply promptly may result in disqualification from the exam. NAME: _________________________________ SIGNATURE: ____________________________
University of Arizona Department of Electrical & Computer Engineering
ECE 220 Basic Circuits
Final Examination December 13, 2016
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Formula Sheet
๐ฅ๐ฅ(๐ก๐ก) = ๐ฅ๐ฅ(โ) + ๐ด๐ด1๐๐๐ ๐ 1(๐ก๐กโ๐ก๐ก0) + ๐ด๐ด2๐๐๐ ๐ 2(๐ก๐กโ๐ก๐ก0) ๐ฅ๐ฅ(๐ก๐ก0) = ๐ฅ๐ฅ(โ) + ๐ด๐ด1 + ๐ด๐ด2 ๐ฅ๐ฅโฒ(๐ก๐ก0) = ๐ ๐ 1๐ด๐ด1 + ๐ ๐ 2๐ด๐ด2 ๐ฅ๐ฅ(๐ก๐ก) = ๐ฅ๐ฅ(โ) + (๐ต๐ต1cos [๐๐๐๐(๐ก๐ก โ ๐ก๐ก0)] + ๐ต๐ต2sin [๐๐๐๐(๐ก๐ก โ ๐ก๐ก0)])๐๐โ๐ผ๐ผ(๐ก๐กโ๐ก๐ก0) ๐ฅ๐ฅ(๐ก๐ก0) = ๐ฅ๐ฅ(โ) + ๐ต๐ต1 ๐ฅ๐ฅโฒ(๐ก๐ก0) = โ๐ผ๐ผ๐ต๐ต1 + ๐๐๐๐๐ต๐ต2 ๐ฅ๐ฅ(๐ก๐ก) = ๐ฅ๐ฅ(โ) + [๐ท๐ท1(๐ก๐ก โ ๐ก๐ก0) + ๐ท๐ท2]๐๐โ๐ผ๐ผ(๐ก๐กโ๐ก๐ก0) ๐ฅ๐ฅ(๐ก๐ก0) = ๐ฅ๐ฅ(โ) + ๐ท๐ท2 ๐ฅ๐ฅโฒ(๐ก๐ก0) = ๐ท๐ท1 โ ๐ผ๐ผ๐ท๐ท2
๐ ๐ 1, ๐ ๐ 2 = โ๐ผ๐ผ ยฑ ๏ฟฝ๐ผ๐ผ2 โ ๐๐02
Parallel RLC ๐ผ๐ผ = 1
2๐ ๐ ๐ ๐
Series RLC ๐ผ๐ผ = ๐ ๐
2๐ฟ๐ฟ
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Part I.
1. Find the power delivered by the circuit element when ๐ 5 ๐A and ๐ฃ 2 V.
a) 10 Wb) 10 Wc) 10 ๐Wd) 10 ๐We) none of these
2. Is the circuit valid?
a) yesb) noc) depends on the value of Bd) depends on the value of De) not enough information given
3. Find ๐ .
a) 0.5 ๐b) 1.0 ๐c) 1.5 ๐d) 2.0 ๐e) none of these
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4. What is the max power that can be delivered to the 4 resister? Hint: Donโt make hasty assumptions. a) 8 W b) 16 W c) 32 W d) 64 W e) none of these
5. Find ๐ฃ . The power rails are 12 V.
a) 12 V b) 12 V c) 10 V d) 10 V e) none of these
6. Find the equivalent capacitance. a) 1.44 10 F b) 16 ๐F c) 16 10 F d) 1440 ๐F e) none of these
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7. Find ๐ฃ ๐ก ๐ฃ ๐ก ๐ฃ ๐ก .
๐ฃ ๐ก 3sin 200๐๐ก 240ยฐ
๐ฃ ๐ก 7cos 200๐๐ก 190ยฐ
a) 8.5 cos(200t + 9.4ยฐ) b) 9.9 cos(200t โ 16.0ยฐ) c) 4.3 cos(200t โ 176.2ยฐ) d) 6.6 cos(200t + 144.7ยฐ) e) none of these 8. By how much does ๐ฃ lag ๐?
a) 45ยฐ b) 90ยฐ c) 90ยฐ d) 45ยฐ e) none of these
9. Find ๐ ๐ก .
a) 0.8cos 10๐ก 135ยฐ A b) 0.42cos 10๐ก 13.4ยฐ A c) 8cos 10๐ก 45ยฐ A d) 0.42cos 10๐ก 103.4ยฐ A e) none of these
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10. Find ๐ฃ ๐ก at ๐ก 2.5 ๐s.
a) 59.3 V b) 0 V c) 50.1 V d) 60 V e) none of these
11. At what frequency is ๐ purely resistive? a) 100 ๐Hz b) 15.9 ๐Hz c) 1.4 ๐HZ d) 0 ๐Hz e) none of these
12. Find ๐ at terminals ๐ and ๐. a) 5 ๐5 b) 10 c) 5 ๐5 d) 0 e) none of these
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Part II. 13. The voltage applied to a 10 ๐ resister is shown below. Find the total energy absorbed by the resister. a) 1066.67 J b) 533.33 J c) 600 J d) 1200 J e) none of these
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14. The box labeled โcircuitโ is the same in all three figures below. When two different voltage sources are connected at the terminals of the circuit, the currents are as shown in the first two figures below. Find the amount of power that would be delivered by the circuit to the 5 resistor in the third figure. a) 400 W b) 80 W c) 720 W d) 0 W e) none of these
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15. Suppose the 10 V full scale meter shown below is used to measure the voltage across the 250 resistor. What will be the percentage error of the reading? % error = (measured โ true)/true 100%. a) 1.6 % b) 2.0 % c) 2.4 % d) 2.8 % e) none of these
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16. Find ๐ .
a) 12 V b) 16 V c) 36 V d) 52 V e) none of these
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17. Find ๐ฃ . The power rails are ยฑ7 V.
a) 1.25 V b) 1.50 V c) 1.75 V d) 2.0 V e) none of these
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18. The switch has been in the โleft positionโ for a long time. Find ๐ฃ ๐ก for ๐ก 40 s. a) 1.43 V b) 0.35 V c) 0.74 V d) 1.43 V e) none of these
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19. Find Zab. a) 4.3 ๐1.1 b) 3.6 ๐0.8 c) 5.5 ๐2.9 d) 9.8 ๐7.9 e) none of these
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20. Find ๐. a) 57.2 โ ๐52 V b) 8.8 โ ๐60 V c) 16.1 ๐12.1 V d) 13.2 โ ๐8 V e) none of these
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21. Find ๐ผ. a) 0.25 + ๐1.75 A b) 2 + ๐1 A c) 0.25 โ ๐1.75 A d) 2 + ๐1 A e) none of these
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22. Find ๐. a) 9.72โ 94.30ยฐ V b) 0.45โ 12.72ยฐ V c) 2.43โ 4.30ยฐ V d) 5.82โ -13.59ยฐ V e) none of these
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23. Which phasor diagram can be (approximately) correct?
e) none of these
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24. Find ๐ผ. a) 125โ -143.13ยฐ A b) 5โ -143.13ยฐ A c) 200โ -143.13ยฐ ๐A d) 320โ -143.13ยฐ ๐A e) none of these
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EXTRA CREDIT: 25. What is the ECE 220 class favorite non-ECE course? a) Psychology b) Discrete Math c) Personal and Consumer Finance d) Linear Algebra e) Conversational Spanish 26. What is Professor Marcellinโs favorite answer for the ECE 220 class favorite non-ECE course? a) Psychology b) Discrete Math c) Personal and Consumer Finance d) Linear Algebra e) Conversational Spanish
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Answers
1. d 2. b 3. c 4. d 5. d 6. a 7. c 8. c 9. d 10. d 11. b 12. a 13. a 14. b 15. c 16. d 17. c 18. c 19. a 20. b 21. d 22. a 23. c 24. A 25. B 26. c