ENGR 217 Practice Exam
Fall 2019
Based on Questions written by Sections 519 and 520
1. Convert 00101001 binary to hexadecimal and to decimal.
2. What is the largest digital value that can be output by a 16 bit ADC?
3. Explain how a Flash type ADC works and provide an advantage and a disadvantage of it vs. a
successive approximation type.
4. Explain how a DAC (digital to analog converter) works (conceptually anyway).
5.
Finite differences for Quiver program: You have taken some data and are using a spreadsheet (Excel) to
get the data into the right format to input to the Quiver program. Below is a snippet of data.
ΔΦ
You suspect that the X finite first difference ΔX [𝑐𝑒𝑙𝑙 𝐹2] is messed up (has a mistake in the formula).
You select on the equation for that cell and Excel highlights the formula as shown. Is there a mistake,
and if so, what is it? How do you fix it?
6. Consider the following Project Network Diagram with all task times in days
a. Label activities with ES, EF, LS, LF
b. Identify the critical path
c. Assume Activity E actually takes 5 time units; how much longer will the project take assuming
no impact on other tasks? Why?
D, 6
Start
A, 3
B, 1
C, 4
L, 3
K, 2
End
H, 6
E, 3
J, 3
G, 4
F, 4
I, 3
[https://www.researchgate.net/figure/Project-network-diagram-for-construction-example_fig3_260787356]
7. Calculate the generated EMF of a D.C. motor with the following parameters: magnetic flux is 52 W, 6
armature conductors, 14 generator poles and 3 parallel paths and speed is 32rpm. (Change the numbers
as you wish, ha, ha .
8. Given the following electrical circuit;
a. Suppose 𝑅2 = 300Ω and 𝑅3 = 500Ω, create a formula for R (V, i, R2, and R3).
b. Solve for R.
c. Suppose R2=2𝛺 and R3=3𝛺 (the number the students wrote on their actual question, solve for R).
What did you get? Why is this a problem?
𝑅
𝑅2 = 300 Ω
𝑅3 = 500 Ω
12𝑉. 𝐷. 𝐶.
i=0.05A
9. Label the 7 parts of the D.C. Motor pictured indicated by the arrows below:
https://www.electrical4u.com/construction-of-dc-motor/
10. What are the four materials displayed in Daniel Rozin’s work: “ Materials and Engineering”
11. What are primary differences between a microprocessor and a micro-controller?
12. Pictured is an Arduino Uno R3.
a.
b.
c.
d.
What is the primary intended function of pins 0-13?
What is the primary intended function of pins A0-A5?
What is the purpose of pins labeled GND, 5V, and 3.3V?
What does the push button in the upper left hand corner do?
13. Picture below is of a breadboard with a transistor plugged into it. The blue, green, and orange leads were
plugged into an Arduino and a D.C. Motor by a T-sip. Will this TU engineered circuit work? If not, how
will an Aggie engineering student re wire it?
14. What are four types of noise we discussed in class?
15. (W4) Assume a circuit has an effective resistance of 1000𝛺 and is running at about 5Volts. It is being
sampled with a 20 bit ADC at a rate of 1MHz.
a. Calculate the predicted Shot current noise.
b. Convert that current to an effective voltage.
c.
Calculate the sensitivity of the ADC (volts/step)
d. Divide (b.) by (c.)
e. What is your conclusion?
16. Given an aluminum wire conductor (power line for example): ρ=2.63E-8 (𝛺 m) and α = 4.4E-3 (deg-1).
What is the percentage increase in resistance between 68°F and 120°F (A very hot afternoon in Phoenix
or Las Vegas in summer)?
17. What is the difference between compiling and interpreting as it relates to a computer program? Which
one is faster?
18. Ethics ABET learning outcomes 2&4 asked in relation to a case study:
To respond to market pressure (Airbus announced a new, more fuel efficient competitor), Boeing redesigned their most
popular commercial aircraft, the 737, to create two more fuel efficient versions (737-MAX8 and 737-MAX9) by replacing
the engines with a new design that included a larger fan. However, because the wing height clearance was too low, the
engines were repositioned to be ahead of the leading edge of the wing and higher such that the top of the fan cowling was
above the top edge of the wing. This new engine position caused the plane, under certain conditions, to behave differently as
compared to previous models of the 737. Boeing decided to solve this difference in flight characteristics by adding a software
control system known as MCAS. MCAS used a single Angle of Attack (AOA) sensor to measure the angle between the onrushing air and the centerline of the fuselage) to automatically keep the plane from stalling. Should the sensor measure that
the plane’s nose was too high (early indicator that a stall may occur), MCAS was designed to raise the elevator thus lowering
the nose of the plane to avert a stall. In two accidents (LionAir in Oct. 2018 and Ethiopian Airlines in March of 2019), the
single (though the plane was equipped with two) AOA sensor used by MCAS malfunctioned and sent erroneous information
to the MCAS control system causing the plane to send the planes into a steep and uncontrollable dive.
Also, note the following: during development, the FAA was not told of this system; the FAA (Federal Aviation Agency)
allowed Boeing to self-certify this system as being safe; before the LionAir crash, pilots were not told of MCAS, much less
how it worked, or what to do if it malfunctioned; and after the first accident, Boeing told FAA about MCAC and FAA
realized they didn’t understand how the system really worked, yet allowed all 737-MAX planes to continue to fly.
Which portions of the ABET student outcomes relate to the overall failure of the MCAS system in terms of design,
implementation, lack of redundancy, lack of informed consent that resulted in the loss of 346 lives and two aircraft? What
measures should Boeing and the FAA have taken in design and approval of this new plane model?
19. What are the three major components of Arduino C/C++ code?
20. What do the A&K pins do on 1602 liquid crystal display we used in lab?
21. What is the difference between sensitivity and resolution?
22. A D.C. motor acts as which? transformer or gyrator
⃑⃑ 𝑥𝐵
⃑⃑ This is a vector equation:
23. Lorentz Equation: 𝐹⃑ = 𝑞𝐸⃑⃑ + 𝑞𝑉
a. 𝑞𝐸⃑⃑ represents the force on a charged particle within an electric field E.
One particle has a vertical downward force indicated on it and the other has a vertical upward
force indicated on it. Add a marking to each to show which one is an electron (negatively
charged) and which one is a proton (positively charged).
⃑⃑ 𝑥𝐵
⃑⃑ represents the force on a charged particle passing through a magnetic field B at some
b. 𝑞𝑉
velocity v.
State the vectors associated with your two fingers and your thumb in using the right hand rule.
Use that information to indicate the direction of the particle (remember, “+” means into the
paper, and “-” means out of the paper).
24. Imagine you have built a RC low pass filter:
a. By definition, at the cutoff frequency, the measured output is 0.707 * input. What is the value of
“gain” in dB?
b. At some lower frequency, the gain is even less at 0.5 * input. What is the value of “gain” in dB?