302, EE Introduction to Electrical and Computer Engineering - Honors Dr. Archie Holmes, Jr. Exam #1
Name: _________________________________________________________________ EID: ________________
Please remember....
Read the entire exam before starting All answers must include units and an appropriate number of significant figures If you feel you need more information than is given, please ask!!! Show all work for credit!!! All final answers MUST BE placed in the space provided; work can be on a separate page. Relax!!!
This exam contains 5 problems Give units to all answers where applicable
Problem #1 Problem #2 Problem #3 Problem #4 Problem #5 Total
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This information will be provided when I return the exam
Class Average = _______ Standard Deviation = _______
PROBLEM #1: CONCEPTUAL QUESTIONS (18 POINTS)
For each of the questions below, circle the correct response. The questions have Roman numerals and are in italics. I. Kirchhoff's Current Law (KCL) is a statement of the law of a.) b.) c.) d.) the conservation of energy. the conservation of charge. the conservation of both energy and charge. the conservation of electron momentum.
II. Kirchhoff's Voltage Law (KVL) is a statement of the law of a.) b.) c.) d.) III. the conservation of energy. the conservation of charge. the conservation of both energy and charge. the conservation of electron momentum. In the circuit below, switch SW1 is in the "open" position.
I
If SW1 is "closed", the current I will a.) b.) c.) d.) decrease to one-half of the value shown. remain approximately the same. increase to twice the value shown. become equal to zero.
IV. Identify the path of the current in the following circuit.
a.)
b.)
c.)
d.)
NONE of these choices.
Use the circuit below for the next three questions
V. If, AMMETER 1 reads 20 mA, the reading on AMMETER 2 is a.) 0 mA b.) 5 mA c.) 10 mA d.) 20 mA VI. If, AMMETER 1 reads 20 mA, the reading on AMMETER 3 is a.) b.) c.) d.) 20 mA 10 mA 5 mA 0 mA
VII. Which of the following statements about the readings of AMMETER 2 and AMMETER 3 is FALSE? a.) b.) c.) d.) VIII. they should be equal to one-half of the reading of AMMETER 1. they should be the same since resistors R2 and R3 are identical. the addition of the readings of AMMETER 2 and AMMETER 3 should be equal to the reading of AMMETER 1. they should be different since resistors R2 and R3 are in parallel. What is the value of the potential difference between points A and B in the circuit below.
A. B. C. D.
0V 3V 6V 12 V
IX.
Which of the following circuits is equivalent to the circuit shown below?
a.)
b.)
c.)
d.)
PROBLEM #2: RESISTIVE CIRCUITS (18 POINTS)
Consider the circuit below. Another copy of this circuit appears on the next page for you to do your work there if you wish.
a)
Assume that all odd resistors (R1, R3, R5, and R7) have half the resistance of the even ones. What is the value of each resistor if a source that is attached between points A and B sees an resistance of 26 k. Make sure that your final answers go in the table below.
Resistors
R1, R3, R5, and R7 R2, R4, R6, and (k)
b)
Complete R6
Value the table below if by a source, which is connected between points A and B, causes resistor R4 to absorb 480 W of power. You can chose your source to either be an ideal voltage source or an ideal current source. Make sure that your final answers go in the
table.
Element Circle the Appropriate Value Value (include units) current absorbed absorbed Value of Ideal Source voltage Ideal Source Resistor R3 delivered delivered
PROBLEM #3: GENERAL CIRCUIT ANALYSIS I (20 POINTS)
Solve for the power being absorbed or generated by each of the circuit elements in the circuit below. The circuit appears again on the next page if you want to do your work here. Make sure that your
final answers go in the table below.
Element 10-V voltage source 2-A current source
Circle the Appropriate Value Value in W delivered delivered absorbed absorbed absorbed absorbed absorbed
2Ix-A current source delivered 1 resistor 2 resistor delivered delivered
PROBLEM #4: GENERAL CIRCUIT ANALYSIS II (24 POINTS)
Consider the circuit below.
At time equals zero (t = 0), all of the switches (S1, S2, and S3) are closed. Plot the power being (i) delivered by the 10-V voltage source and (ii) absorbed by the 24 resistor as a function of time between 0 and 20 s if the following occurs: Switch S2 opens at t = 5 s Switch S3 opens at t = 10 s Switch S1 opens at t = 15 s
Clearly mark the values on your plots and labels (with units) for your axes. The circuit appears again on the next page if you want to do your work here
Provide your final answers in the space below.
PROBLEM #5: STEREO LIGHTING DESIGN (20 POINTS)
You have been hired by an electronic hobbyist for some consulting work. The hobbyist has build her own stereo amplifier and want to add a back-lit display to it. She has selected five different bulbs for the display. Two of them (#1 and #2) each dissipate 180 mW when operated at 12V; the other three (#3, #4, and #5) each dissipate 45 mW when operated at 9V. Within her design, the hobbyist has a stable, highquality 12-V supply which you can use for power. Given this information, design the display with the following performance criteria: 1) Each light bulb can be independently turned on and off 2) Light bulbs #1 and #2 must get 12 V from the power supply at all times. 3) The other light bulbs must get 9 5% V from the power supply at all times. Your answer to this question should provide both a schematic (i.e., circuit diagram) and a brief proof that it works as expected. Make sure that the circuit diagram is placed in the box provided. You may use the following three pages on which to show your work. Hint: This problem requires you to think about what is happening much more than doing math...
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EXAM #1 CONTEST
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Please complete the section below if you wish to participate in this contest. The winner will receive lunch on me at the end of the semester. There are no points associated with this part of the exam.
Name: _________________________________________________________________ Score of the Texas-OU Football Game Texas: ______ Tiebreakers: Which team will score first?: _________________ Rushing Yards Gained by Texas: ________ OU: ______