1 ECE 201 – Fall 2009 Final Exam December 16, 2009 Division 0101: Tan (11:30am) Division 0201: Clark (7:30 am) Division 0301: Elliott (1:30 pm) Instructions 1. DO NOT START UNTIL TOLD TO DO SO. 2. Write your Name, division, professor, and student ID# (PUID) on your scantron sheet. 3. This is a CLOSED BOOKS and CLOSED NOTES exam. 4. There is only one correct answer to each question. 5. Calculators are allowed (but not necessary). Please clear any formulas, text, or other information from your calculator memory prior to the exam. 6. If extra paper is needed, use back of test pages. 7. Formulas are given on the final page of this exam. 8. Cheating will not be tolerated. Cheating in this exam will result in an F in the course. 9. If you cannot solve a question, be sure to look at the other ones and come back to it if time permits. 10. As described in the course syllabus, we must certify that every student who receives a passing grade in this course has satisfied each of the course outcomes. On this exam, you have the opportunity to satisfy all outcomes. (See the course syllabus for a complete description of each outcome.) On the chart below, we list the criteria we use for determining whether you have satisfied these course outcomes. You only need to satisfy the outcomes once during the course, so any outcomes that you satisfied previously will remain satisfied, independent of your performance on this exam. Course Outcome Exam Questions Minimum correct answers required to satisfy the course outcome i 1-3, 5 2 ii 16 1 iii 4, 9, 18, 27 2 iv 6-7 1 v 11-18 4 vi 19-22 2 vii 23-26 2 viii 27 1 ix 8-10 12 1. Determine the voltage Vz. (1) −15V (2) −10V (3) −7.5V (4) −5V (5) 0 (6) 5V (7) 7.5V (8) 10V (9) 15V 2. For the circuit shown below, the current I is: (1) 0A (2) 2A (3) 5A (4) −6A (5) 6A (6) −10A (7) 10A3 3. The voltage Vx in the circuit shown below is: (1) −33V (2) −21V (3) −9V (4) −3V (5) 3V (6) 9V (7) 21V (8) 33V 4. The circuit shown below has two independent sources V1 and I2. The output voltage Vout has been measured for two combinations of input sources: V1 I2 Vout 2 V 5 A 12 V 4 V −2.5 A −1 V What would the value of Vout be for V1= 1 V and I2= 1 A? (1) 1 V (2) 2 V (3) 3 V (4) 4 V (5) 5 V (6) 6 V (7) 0 V4 5. The capacitor is uncharged at t = 0 (i.e. Vc(0+) = 0). Determine Vc at t = 2 sec. (1) −10 V (2) −8.65 V (3) −5 V (4) −1.35 V (5) 0 (6) 1.35 V (7) 5 V (8) 8.65 V (9) 10 V 6. The switch in the RL circuit shown below has been open for a long time and closes at t=0 s. Find the inductor current iL(t) for t > 0. (1) ( )10t2 2e−− A (2) ( )10t2 2e−+ A (3) ( )10t4 4e−− A (4) ( )10t4 4e−+ A (5) ( )10t4 2e−− A (6) ( )10t4 2e−+ A (7) none of the above5 7. Determine the rate of change in the inductor current at t = 0+, ( )( )0'0LLtdi tidt++== in the circuit below. (1) 0 A/s (2) 2 A/s (3) 3 A/s (4) 5 A/s (5) -5 A/s (6) -3 A/s (7) -2 A/s (8) -1 A/s 8. Given an input voltage of 4V, what is the output voltage Vout of this circuit containing an ideal operational amplifier? (1) 0 (2) 5 V (3) 10 V (4) 20 V (5) 40 V (6) -20 V (7) -10 V (8) -5 V6 9. Assume an ideal operational amplifier and that the capacitor is uncharged at t = 0. Find the correct expression for the output voltage Vo(t) in volts for t > 0 where t is in seconds. (1) t (2) t + 3 (3) t + 1/4 (4) 4t + 2 (5) 4t + 3 (6) t + 4 (7) 2t + 1/4 10. In the Op Amp circuit below, the Thévenin equivalent resistance Rth at the inverting input is: (1) −3 kΩ (2) −2 kΩ (3) −1 kΩ (4) −0.5 kΩ (5) 0 kΩ (6) 0.5 kΩ (7) 1 kΩ (8) 2 kΩ (9) 3 kΩ7 11. The current phasor I in the circuit below is: (1) − j100 A (2) − j10 A (3) − j1 A (4) 0 A (5) j1 A (6) j10 A (7) j100 A 12. At ω = 2π rad/s, the phasor current through the element shown below is rms2 ( 45 )A= ∠− °I. Determine the voltage v(t) across the element. (1) 0 (2) ( )2sin 2 t Vπ (3) ( )2 2 cos 2 t Vπ (4) ( )2sin 2 t 45 Vπ− ° (5) ( )2cos 2 t 45 Vπ− ° (6) ( )2 2 sin 2 t 45 Vπ+ ° (7) ( )2 2 cos 2 t 45 Vπ+ °8 13. The phasor current I for the node sketched below has a magnitude of: (1) 0 A (2) 1 A (3) 3 A (4) 2 A (5) 5 A (6) 7 A (7) 12 A 14. The mesh current phasor I1 in the circuit below is: (1) 1∠0° A (2) 2∠0° A (3) j1 A (4) j2 A (5) (1+j) A (6) (1+2j) A (7) (2+j) A (8) (2+2j) A9 15. At ω = 2 rad/s, the impedance ZTH(jω) = (2 + j2Ω) shown in the circuit below can be realized with: (1) a single 1Ω resistor (2) a single 2Ω resistor (3) a single 1Η inductor (4) a single 2H inductor (5) a 1Ω resistor in series with a 1Η inductor (6) a 1Ω resistor in series with a 2Η inductor (7) a 2Ω resistor in series with a 1Η inductor (8) a 2Ω resistor in series with a 2Η inductor10 16. The circuit below contains a floating voltage source. The voltage phasors at nodes A and B are VA and VB, respectively. The correct nodal equation involving the super node (containing both nodes A and B) is: (1) VA = 5∠0° V (2) VB =10∠0° V (3) (1+j)VA + jVB = −5∠0° V (4) (1+j)VA + (1+j)VB = 15∠0° V (5) (2+j)VA + jVB = −5∠0° V (6) (2+j)VA + (2+j)VB = 15∠0° V (7) (1+2j)VA + 2jVB = −5∠0° V (8) (1+2j)VA + (1+2j)VB = 15∠0° V 17. In the circuit shown below, let is(t) = 2.5 cos(ωt) A, with the frequency ω variable. As ω is varied, we measure the amplitude of the voltage across the capacitor as shown in the plot to the right. Determine C. (1) 1 µF (2) 2 µF (3) 5 µF (4) 10 µF (5) 20 µF (6) 50 µF (7) 100 µF (8) 200 µF11 18. Find the Thévenin equivalent of the following network. The value of the source Vth and impedance Zth are: (1) Vth = 5V, Zth = 5Ω (2) Vth = …
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