Introduction to Electrical Engineering Laboratory

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Laboratory manual series for basic Electrical
Engineering
Introduction to Electrical Engineering
Laboratory
By Isuru Premaratne
Version: 2016 January
Introduction to Electrical Engineering Laboratory by Isuru Premaratne is licensed under a Creative
Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Based on a work by James M. Fiore at http://www.dissidents.com/books.htm.
For more information or feedback, contact:
Isuru Premaratne
isuru109@outlook.com

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Introduction to Electrical Engineering
Laboratory
Objective
The laboratory emphasizes the practical, hands-on component of this program of study. It
complements the theoretical material presented in lecture, and as such, is integral and indispensable
to the mastery of the subject. There are several items of importance here including proper safety
procedures, required tools, and laboratory reports. This exercise will finish with an examination of
scientific and engineering notation, the standard form of representing and manipulating values.
Lab Safety and Tools
If proper procedures are followed, the electrical lab is a perfectly safe place in which to work. There
are some basic rules: No food or drink is allowed in lab at any time. Liquids are of particular danger
as they are ordinarily conductive. While the circuitry used in lab is normally of no shock hazard,
some of the test equipment may have very high internal voltages that could be lethal (in excess of
10,000 volts). Spilling a bottle of water or soda onto such equipment could leave the experimenter in
the receiving end of a severe shock. Similarly, items such as books and jackets should not be left on
top of the test equipment as it could cause overheating.
When you enter the laboratory for the first time, please identify the following points.
1. Entrance main door
2. Emergency exit
3. Fire assembly point
4. Main circuit breaker
5. Where the instruments are kept
6. First aid box
Note the general time schedule for the laboratory
1. Starting time of lab session
2. Ending time of lab session
3. Lunch time
Each time a lab session being conducted, there will be an instructor in-charge for the session. You all
are required to report the instructor for all activities you are doing at the lab. If you want to leave the
lab during an ongoing lab session, please inform the instructor. If you adhere to the rules and
regulations the laboratory will be a pleasant place to learn.

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Each lab workstation (work bench) is self-contained. All test equipment is arrayed along the bench.
At the back of the work area there is a power strip. All test equipment for this workstation should be
plugged into this strip. None of this equipment should be plugged into any other strip. This strip is
controlled by a circuit breaker. In the event of an emergency, all test equipment may be powered off
through this one switch. Further, the benches are controlled by dedicated circuit breakers in the front
of the lab. Also there are A/B/C class fire extinguishers suitable for electrical fires. The first aid kit is
available in the laboratory. This contains bandages, cleaning swaps etc. For serious injury, the in-
charge of the lab will be contacted.
A lab bench should always be left in a secure mode. This means that the power to each piece of test
equipment should be turned off, the bench itself should be turned off, all AC and DC power and
signal sources should be turned down to zero, and all other equipment and components properly
stowed with lab stools pushed under the bench.
It is important to come prepared to lab. This includes the class text, the lab exercise for that day, class
notebook, calculator, and hand tools. The tools include a breadboard, test leads, wire strippers, and
needle nose pliers. A small pencil soldering iron may also be useful. A basic DMM (digital
Multimeter) rounds out the list.
A typical breadboard or Protoboard is shown below:
This particular unit features two main wiring sections with a common strip section down the center.
Boards can be larger or smaller than this and may or may not have the mounting plate as shown. The
connections are spaced 0.1 inch apart which is the standard spacing for many semiconductor chips.
These are clustered in groups of five common terminals to allow multiple connections. The exception

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is the common strip which may have dozens of connection points. These are called buses and are
designed for power and ground connections. Interconnections are normally made using small
diameter solid hookup wire, usually AWG 22 or 24. Larger gauges may damage the board while
smaller gauges do not always make good connections and are easy to break.
In the picture below, the color highlighted sections indicate common connection points. Note the long
blue section which is a bus. This unit has four discrete buses available. When building circuits on a
breadboard, it is important to keep the interconnecting wires short and the layout as neat as possible.
This will aid both circuit functioning and ease of troubleshooting.
Laboratory Reports
The work carried out during the lab session and the conclusion you made should be presented to the
supervisor formally in the form of a report. Evaluation of the lab activities will be based on this
report. Also the report is the reference material for your later studies as well. Therefore the students
must pay special attention on preparing lab reports. Follow the guidelines given below when writing a
lab report.
Cover page and writings
1. Cover page is the outermost page of a report. Details of the borders, font size will be given by
the institution. In general the cover page should include,
a. Course code and title
b. Title of the experiment
c. Presenter’s name, registration number and group
d. Date of completion of lab experiment
e. Date of submission of report

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2. Always write on one side of the paper.
3. Only graphs should be pasted on the left hand side, which should be just before the table of
results of the respective graph.
4. Avoid using red ink
5. Pages should be numbered.
6. Bind it properly.
Use correct grammar, spellings and language format.
1. Use passive voice.
2. Avoid first person pronouns. (I, we, me, us)
3. Use formal language. Do not express personal feelings and achievements.
Maintain the correct order of proceedings
1. Title: Write the full title of the experiment. This is always given in the guidelines of the
particular lab session.
2. Objectives: This is what you are going to achieve after completion of the laboratory task.
Usually given in the lab guidelines. Otherwise the instructor will give it at the beginning.
3. Apparatus: List down all the instruments used for the lab session. Priority should be given
for the most important or the most used instrument. Correct names and information of each
instrument should be asked from the instructor.
4. Theory: All practical session are designed to practically implement a theory. Therefore this
section is to brief the relevant theory. (Eg: Ohm’s law equation, Kirchhoff’s law equations
etc.)
5. Preparatory tasks/Calculations: In a lab session always there is a preparatory task which
will give a preliminary idea about what will be done during the lab session. It is usually a set
of calculations which are going to be tested practically thereafter.
6. Procedure: This section describes the steps carried out to perform the practical. Always write
this in steps. Do not write long paragraphs. Should be clear and specific. Use diagrams and
sketches wherever necessary. Name the figures and mention them in where they are
significant.
7. Results: All the readings and observation should be included in this section. Measurements,
screenshots etc. Better to use tabular form always where applicable.
8. Analysis: In a lab guideline there will be calculations based on results. Graphs, proving
equations etc. Actually the data you have taken from the results section should be processed
to get information in this section.
9. Conclusion: Compare the objectives and the results. Indicate briefly whether you have
achieved the objectives.
10. Discussion: Anything related to experiments can be discussed here. Reasons for errors,
difficulties faced, assumptions made and suggesting improvements.
The lab report is a student’s personal endeavor. Therefore avoid plagiarism. Discuss with your
colleagues but do not copy from them. Do not allow others to copy from your own work.

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Scientific and Engineering Notation
Scientists and engineers often work with very large and very small numbers. The ordinary practice of
using commas and leading zeroes proves to be very cumbersome in this situation. Scientific notation
is more compact and less error prone method of representation. The number is split into two portions:
a precision part (the mantissa) and a magnitude part (the exponent, being a power of ten). For
example, the value 23,000 could be written as 23 times 10 to the 3rd
power (that is, times one
thousand). The exponent may be thought of in terms of how places the decimal point is moved to the
left. Spelling this out is awkward, so a shorthand method is used where “times 10 to the X power” is
replaced by the letter E (which stands for exponent). Thus, 23,000 could be written as 23E3. The
value 45,000,000,000 would be written as 45E9. Note that it would also be possible to write this
number as 4.5E10 or even .45E11. The only difference between scientific notation and engineering
notation is that for engineering notation the exponent is always a multiple of three. Thus, 45E9 is
proper engineering notation but 4.5E10 isn’t. On most scientific calculators E is represented by either
an “EE” or “EXP” button. The process of entering the value 45E9 would be depressing the keys 4 5
EE 9.
For fractional values, the exponent is negative and may be thought of in terms how many places the
decimal point must be moved to the right. Thus, .00067 may be written as .67E-3 or 6.7E-4 or even
670E-6. Note that only the first and last of these three are acceptable as engineering notation.
Engineering notation goes one step further by using a set of prefixes to replace the multiples of three
for the exponent. The prefixes are:
Power of ten Prefix name Prefix
E12 Tera T
E9 Giga G
E6 Mega M
E3 kilo k
E0
E-3 milli m
E-6 micro µ
E-9 nano n
E-12 pico p
Thus, 33,000 volts could be written as 33E3 volts or simply 33 kilovolts. (33 kV)
Besides being more compact, this notation is much simpler than the ordinary form when manipulating
wide ranging values. When multiplying, simply multiply the precision portions and add the
exponents. Similarly, when dividing, divide the precision portions and subtract the exponents. For
example, 23,000 times .000003 may appear to be a complicated task. In engineering notation this is
23E3 times 3E-6. The result is 69E-3 (that is, .069). Given enough practice it will become second
nature that kilo (E3) times micro (E-6) yields milli (E-3). This will facilitate lab estimates a great

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deal. Continuing, 42,000,000 divided by .002 is 42E6 divided by 2E-3, or 21E9 (the exponent is 6
minus a negative 3, or 9).
When adding or subtracting, first make sure that the exponents are the same (scale if required) and
then add or subtract the precision portions. For example, 2E3 plus 5E3 is 7E3. By comparison, 2E3
plus 5E6 is the same as 2E3 plus 5000E3, or 5002E3 (or 5.002E6).
Perform the following operations.
1. Convert the following into scientific and engineering notation.
a). 1,500
b). 63,200,000
c). 0.0234
d). 0.000059
e). 0.170
2. Convert the following into normal longhand notation:
a). 1.23E3
b). 54.7E6
c). 2E-3
d). 27E-9
e). 4.39E7
3. Use the appropriate prefix for the following:
a). 132E3 volt
b). 5.6E6 ohm
c). 3.3E-6 Ampere
d). 0.005 volt
e). 0.000068 watt
4. Perform the following operations:
a). 5.2E6 + 1.7E6
b). 12E3 – 900
c). 1.7E3 × 2E6
d). 48E3 / 4E6
e). 20 / 4E3
f). 10 M × 2 k
g). 8 n / 2 m

Introduction to Electrical Engineering Laboratory

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