Mini-Lab 1
TITLE: PART I - Instrumentation Review, Digital Multimeters and Power Supplies
OBJECTIVE:
• To become familiar with Power Supplies (PS), Digital Multimeters (DMM) and Resistors (R).
Perform resistance, voltage and current measurements.
•
To become familiar with the lab computer login procedure, course website and equipment
manuals which are available on the website for your use.
ASSIGNMENT
In the Log Book, keep a detailed "diary" of the experiment. Report your findings, answering the
questions in the handout, and making any additional observations you feel that are relevant.
PROCEDURE
a) On the computer, open a web browser and proceed to the course homepage
(http://www.engineering.uiowa.edu/~expeng/). You can access the manuals for the
instrumentation on the web site through the “Available Equipment” link. While working on
the lab, feel free to use the manuals on the website.
b) You will be provided with a DMM (HP/Agilent U3402A). You will also use either of two HP
PS, models 6612C and E3620S. The 6612C PS operation is more complicated than the
E3620S, but this difference does not affect this lab.
c) If you have the HP 6612C PS, configure the PS to operate in constant voltage mode with 1 V
of output. Press the “Voltage” button, the “Enter Number” button, followed by the “1”,
followed by “Enter”, and then turn the power supply output on by pressing the “Output
On/Off” button. An example of this type of operation is given on page 42 of the Users’
manual. If you have the HP E3620S, set the dial so the output reads as close to 1 V as
possible. Figure below shows the DMM model HP/Agilent U3402A.
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d) Connect the PS you have (either the 6612C or the E3620S) to the DMM, and record PS and
DMM output making four reading over the range of the PS. To do this you will have to
consult the DMM manual, or use the figure below as a guide. See the Appendix of this
handout for additional operating tips.
e) Select a resistor from the component box in the lab. Measure the resistance using both the two
and four wire methods and compare the results. See below for help:
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Compare your measured resistance using the DMM with that determined from the color code on
the resistor as given below:
Resistor Code
A = 1st digit
B = 2nd digit
C = Exponent of 10
D = Tolerance
It should be read AB x 10c ± D%, and the color code follows the specifications:
A, B, and C
black = 0, brown = 1, red = 2, orange = 3, yellow = 4, green = 5, blue = 6, violet = 7, gray = 8,
white = 9
D
gold = 5% and silver = 10%
Did you find the resistor to be within the tolerance indicated by the color band? In other words,
determine the % difference of the measured value from the color band value, and is this within ±
D%?
f) Set the PS to 2V. Connect the PS, resistor and DMM in series to measure current through R.
Record the value of the current flowing through the resistor. Then reconfigure the connection,
and reconnect the DMM across the resistor to measure the voltage drop across the resistor.
Record all measured values and compare the measurements (V = I R) for the resistor’s voltage
and current flow.
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TITLE: PART II - Instrumentation Review: Oscilloscopes and Signal Generators
OBJECTIVE
You should become familiar with and operate the Agilent InfiniiVision 2002a Oscilloscope,
which has an integrated 20 MHz function generator to provide stimulus output of sine, square,
ramp, pulse, DC and noise waveforms. You will learn how to measure signals using the OS and
how to save the data from the oscilloscope to the PC. After this lab, all group members should be
capable of producing signals and measuring signals using the oscilloscope, acquiring and storing
the signal data on PCs.
PROCEDURE
The InfiniiVision 2002a is a 2-channels Oscilloscope similar to the one shown below (which has 4
channels), with nearly identical operational controls and measurement features. You can find the
user guide on the course website (http://www.engineering.uiowa.edu/~expeng/Equipment/AgilentDSO-X-2002A-Manual.pdf). You should feel comfortable in referring the equipment manuals
when needed.
Follow the procedure below and record what you do, find and measure in the logbook. Feel free to
use functions of the oscilloscope, even if they are not specifically referred to in this write-up.
a) Study the cable connections and button positions/functions of the oscilloscope (pages 28 ~ 35
[1]). Record them in your logbook. Feel free to label or number the knobs and buttons to refer
to them if you need. Your logbook should be complete enough so that if you need to use this
equipment in the future you could do so without consulting the User’s Manual.
b) You will use the built-in waveform generator of the oscilloscope to generate waveforms. Draw
the signal cable output location, connections and important buttons in your logbook so you can
easily reproduce what you do to generate a signal.
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c) Read the “Waveform Generator” section in the User’s guide [1] (pages 205 ~210) to
understand how to generate a waveform. Connect the waveform generator output with the
channel 1 input, testing your operational skills using signals (any type, but be consistent) of
approximately 1 MHz, 1KHz, and 0.5 Hz. Measure each signal using the OS measurement
capabilities (pages 169 ~ 189, Ref. [1]). Record the frequency measured by the OS, and the
frequency generated by the waveform generator.
Group members should take turns at the controls of the oscilloscope. If you don't understand
the operations ask your teammates for an explanation. As you learn how to use the
oscilloscope note the major points of interest and problems you encountered in your Log Book.
It is always good to learn from your experiences too if you run into problems, so note them.
Hints: The “entry knob” could be helpful in quickly adjusting the input values; Try the “Auto
scale” key to automatically adjust and capture the signal. To measure the 0.5 Hz signal you
will probably have to manually adjust the oscilloscope time scale to capture the signal using
“Horizontal controls” (pages 43 Ref. [1]) and/or adjust the vertical scale using “Vertical
controls” (page 55 Ref. [1]). If the OS measurement function does not work, you will need to
manually measure the period of the waveform using the “cursors” (page 159 Ref. [1]) by
measuring the time difference of the peak to peak of the waveform, then the frequency in Hz is
the inverse of the waveform period.
d) Read “Save/Recall” section of the User’s guide (page 211 Ref [1]), understand how to save the
acquired waveform data to a USB storage in specific format (BMP, PNG, CSV, ASCII, etc).
Save the acquired signals (1 MHz, 1 KHz, and 0.5 Hz) in CSV format, report your results
in plots in your logbook (i.e. no need to include the raw data). Make sure that your plots
follow the syllabus requirement, e.g. axes, labels, units, etc.
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Mini-lab 1a Pre-lab Questions
PART I PRE-LAB QUESTION:
For the circuit shown below, answer the following questions:
1
3
2
Resistor
3
Resistor
2
5V
4
Resistor 1
5
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1. If all three resistors are 80 ohms, what is the total resistance of the circuit?
2. If you did not know the value of resistors 1 and 3, and you could freely pick resistor 2,
which of the following options could you use to find the value of resistor 3:
a. Measure ONLY voltages across points 1 through 4 (any combinations).
b. Measure ONLY currents across points 1, 2, 4, or 5 (any combinations).
3. Describe the procedure you would use to find the value of resistor 3 using your selected
option from question 2.
PART II PRE-LAB QUESTIONS:
Read the oscilloscope User’s guide [1] (available on the experimental engineering website) and
familiarize yourself with terminology, triggering, acquiring data, scaling and positioning
waveforms, measuring waveforms, and setting up the oscilloscope. Answer the following
questions. You might also want to read the referenced pages for theoretical background of
sampling and aliasing [2] from your text.
•
•
•
•
•
•
•
Describe the Auto Scale feature. What does it do?
Note how to save and recall setups, how many setups can be saved, and how to securely erase
the setups?
What is one advantage of each of the three acquire modes (in Acquisition Control): Normal,
Peak Detect, Averaging. How do you change the acquisition mode?
What is actually happening when you change the horizontal position of the waveform?
What is signal aliasing?
How fast must the oscilloscope sample the signal to avoid aliasing?
What is one way to check for aliasing?
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REFERENCES
[1] Agilent., TDS Agilent InfiniiVision 2000 X-Series Oscilloscopes User’s Guide.
(http://www.engineering.uiowa.edu/~expeng/Equipment/Agilent-DSO-X-2002A-Manual.pdf)
[2] Figliola, R. S. and Beasley, D. E., Theory and Design for Mechanical Measurements, Fifth Ed.,
Wiley, 2011, pp. 260-269.
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Mini-Lab 1: Appendix
Here are some additional things to know about the HP 34401A DMM.
•
Experiment with the “Auto/Hold” button to take average reading.
•
Similarly, by taking single readings you can sample you data one reading at a time.
•
To change the range follow the instructions below:
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•
To set the digits of resolution:
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