USMANU DANFODIYO UNIVERSITY SOKOTO
FACULTY OF ENGINEERING AND ENVIRONMENTAL
DESIGN
DEPARTMENT OF ELECTRICAL AND ELECTRONICS
ENGINEERING
PRACTICAL MANUAL
for
ELC 210 – Engineering Laboratory I (Electrical Part)
Written By: Adamu Mudi
Course Instructors: Adamu Mudi and Mujahid Abdullahi
Supervised By: Engr. Prof. H. M. Yahya
HOD, Electrical and Electronics Department,
TABLE OF CONTENTS
Contents
Page
INTRODUCTION..............................................................................................................ii
GENERAL LABORATORY SAFETY.................................................................................iii
GENERAL ENGINEERING EXPERIMENT REPORT.......................................................iv
CHAPTER 1 - COMPONENTS IDENTIFICATION.....................................................................1
CHAPTER 2 - RESISTOR COLOUR CODE.........................................................................7
CHAPTER 3 - EXPERIMENT TO VERIFY OHM’S LAW .......................................................10
CHAPTER 4 - EXPERIMENT ON INTERNAL RESISTANCE OF VOLTAGE SOURCE......14
CHAPTER 5 - EXPERIMENT TO VERIFY VOLTAGE DIVIDER THEOREM...................15
CHAPTER 6 - EXPERIMENT TO VERIFY KIRCHOFF’S VOLTAGE LAW......................16
CHAPTER 7 - EXPERIMENT TO VERIFY KIRCHOFF’S CURRENT LAW.......................17
INTRODUCTION
The place of laboratory work in Electrical and Electronics Engineering is very important.
Laboratory course work enables students to identify components and equipments, measure the
values of these components and equipments, and carry out experiments to verify fundamental
laws which include Ohm’s Law, Kirchoff’s Voltage Law, Kirchoff’s Current Law among others.
The laboratory exercises in this manual are designed for the students to experiment on what they
have been taught in theory classes. Therefore, in order to fully understand the principles being
investigated, the student is advised to read extensively on the related topics before entering the
laboratory.
GENERAL LABORATORY SAFETY
Safety is an important factor in any laboratory work. It should be understood that any use of
electricity inherently involves some degree of hazard. The best way to achieve safety in the use
of electrical equipment is to adhere to the safety rules.
The safety rules include:
1. There must be at least two (2) people in the laboratory while working on live circuits.
2. Shoes must be worn at all times.
3. Do not wear long loose ties, scarves, or other loose clothing around machines.
4. No part of a live circuit should be touched with bare hand.
5. Be as neat a possible. Keep the work area and workbench clear of items not used in the
experiment.
6. Always check to see that the power switch is OFF before plugging into the outlet. Also, turn
instrument or equipment OFF before unplugging from the outlet.
7. When unplugging a power cord, pull on the plug, not on the cable.
8. When disassembling a circuit, first remove the source of power.
9. Report any damages to equipment, hazards, and potential hazards to the laboratory instructor.
10. If in doubt about electrical safety, see the laboratory instructor.
GENERAL ENGINEERING EXPERIMENT REPORT
The format for report of the experiments to be conducted is as follows:
1. Experiment number, Title and Date: These should be clearly stated at the beginning of the
report.
2. Objective of the experiment: The aim for which the experiment is conducted.
3. Apparatus: List of apparatus or equipments used in the experiment.
4. Theory: This includes the laws related to the experiment.
5. Circuit Diagram: The circuit should be clearly drawn and labeled.
6. Procedure: This consists of description of connections made, the nature and range of inputs,
how readings are taken and any other step taken in the experiment.
7. Results: Readings obtained should be tabulated where necessary, calculations should be
clearly outlined, graphs where necessary should be neatly drawn.
8. Observation: Difficulties encountered, precautions taken etc should be clearly stated.
9. Conclusion: Comment on the result obtained, whether the result confirms the theory.
If theory is not confirmed, give possible reasons.
CHAPTER 1 – COMPONENTS IDENTIFICATION
1.0 OBJECTIVES:
You should be able to identify each of the following components:







Resistor
Capacitor
Inductor
Diode
Transistor
Integrated Circuit (IC)
Breadboard, Veroboard and Printed Circuit Board (PCB)
1.1 RESISTOR
A resistor is an electronic component that limits the flow of electrical current.
A resistor is typically used to control the amount of current that is flowing in a circuit.
The resistance of a resistor is represented by R.
The S.I unit of resistance is ohms (Ω). Other units are KiloOhms (1K = 103 Ω), MegaOhms
(1M = 106 Ω).
The symbol of resistor is:
OR
In the real world, it looks like this:
1.2 CAPACITOR
A capacitor is an electronic component that stores charge in an electric field.
A capacitor is often used in an electronic circuit as temporary energy-storage device.
The capacitance of a capacitor is represented by C.
The S.I unit of capacitance is farads (F). Other units are microfarads (1μF = 10-6 F), nanofarads
(1nF = 10-9 F), picofarads (1pF = 10-12 F).
The symbol of capacitor is:
OR
In the real world, it looks like this:
+
1.3 INDUCTOR
An inductor is an electronic component that stores charge in a magnetic field.
The inductance of an inductor is represented by L.
The S.I unit of inductance is Henry (H). Other unit is milliHenry (1mH = 10-3 H).
The symbol of inductor is:
In the real world, it looks like this:
1.4 DIODE
A diode is an electronic component that allows current to flow through it in only one direction.
The diagram below shows the symbol of a diode and how it looks in the real world.
When the positive terminal of a voltage source is connected to the anode and the negative
terminal of the voltage source connected to the cathode as shown in the diagram below, the diode
behaves like a closed switch allowing current to flow from the anode to the cathode. In this case,
the diode is said to be forward biased.
When the positive terminal of a voltage source is connected to the cathode and the negative
terminal of the voltage source connected to the anode as shown in the diagram below, the diode
behaves like an open switch blocking current from flowing through it. In this case, the diode is
said to be reversed biased.
1.5 TRANSISTOR
A transistor is a three - terminal electronic component that acts as an amplifier (in analogue
circuit) or as a switch (in digital circuit).
There are different types of transistors: Bipolar Junction Transistor (BJT), Metal Oxide
Semiconductor Field Effect Transistor (MOSFET) etc. In this course, we are focusing on BJT.
BJTs are either NPN or PNP.
The symbol of NPN transistor is:
The symbol of PNP transistor is:
In the real world, it looks like this:
1.6 INTEGRATED CIRCUIT (IC)
An integrated circuit (IC), sometimes called a chip or microchip, is a circuit containing
thousands or millions of tiny resistors, capacitors, and transistors. An IC can function as an
amplifier, oscillator, timer, counter, computer memory, or microprocessor.
Below are some ICs.
1.7 BREADBOARD, VEROBOARD AND PRINTED CIRCUIT BOARD
Breadboard
Breadboard is a plastic with holes for holding and connecting electronic components. It is also
known as solderless breadboard because it enables you to use circuit parts without soldering
them together.
Internal Connection of Breadboard
A circuit constructed using a breadboard
Veroboard
Veroboard is a pre-formed circuit board with copper strips on an insulating surface. It was
invented in the early 1960s by the Electronics Department of Vero Precision Engineering Ltd. It
was introduced as a general-purpose material for use in constructing electronic circuits.
An empty veroboard
A circuit constructed using a veroboard
Printed Circuit Board (PCB)
Printed Circuit Board (PCB) is a purpose-designed circuit board with copper strips on an
insulating surface. Just like veroboard, it provides both mechanical support and electrical
connection for components. The difference between veroboard and PCB is that veroboard is for
general purpose while PCB is customized for a particular circuit. Also PCB is more professional
than veroboard.
An empty PCB
A circuit constructed on a PCB
1.8 EXPERIMENT REPORT
Make a research and write on the following components:
(1) Transformer, (2) Zener Diode (3) Variable Resistor (4) Variable Capacitor (5) and MOSFET
under the following headings:




Definition
Function in a circuit
Symbol
Real world look
CHAPTER 2 – RESISTOR COLOUR CODE
2.0 OBJECTIVES:
You should be able to determine the:


nominal value of a resistor using resistor colour code.
actual value of a resistor using a multimetre.
2.1 EQUIPMENT REQUIRED:


Resistors of the following values: 100Ω, 220Ω, 1K, 8.2K, 10K
A digital multimetre (DMM)
2.2 DISCUSSION
Resistors have standard colours for identification of the resistance value. Below is a table used
for finding the nominal value of a resistor.
COLOUR 1ST DIGIT 2ND DIGIT MULTIPLIER
TOLERANCE
0
Black
0
0
X 10
Silver ±10%; Gold ±5%
1
Brown
1
1
X 10
Silver ±10%; Gold ±5%
2
Red
2
2
X 10
Silver ±10%; Gold ±5%
3
Orange
3
3
X 10
Silver ±10%; Gold ±5%
4
Yellow
4
4
X 10
Silver ±10%; Gold ±5%
5
Green
5
5
X 10
Silver ±10%; Gold ±5%
6
Blue
6
6
X 10
Silver ±10%; Gold ±5%
7
Violet
7
7
X 10
Silver ±10%; Gold ±5%
8
Gray
8
8
X 10
Silver ±10%; Gold ±5%
9
White
9
9
X 10
Silver ±10%; Gold ±5%
Note: The value obtained using colour code is the resistor’s nominal value while the value
obtained from the multimetre is the actual value.
2.3 PROCEDURE
Step 1:
Place the first resistor as shown below:
The resistor contains four colours: brown, black, brown and gold.
The resistor’s nominal value is 10 X 101, ±5% = 100Ω, ±5%.
Which means that the actual value as measured from the multimetre will fall
between 95 Ω and 105Ω.
Step 2:
Place your DMM in the resistance measuring mode, 200Ω range.
Step 3:
Place the red probe on one leg of the resistor and the black probe on the other leg.
Step 4:
Read and record the actual value of the resistor in the space provided below:
R1 = ______________Ω.
Step 6:
Place the second resistor as shown below:
The resistor contains four colours: red, red, brown and gold.
The resistor’s nominal value is 22 X 101, ±5% = 220Ω, ±5%.
Which means that the actual value as measured from the multimetre will fall
between 209 Ω and 239Ω.
Step 7:
Place your DMM in the resistance measuring mode, 2000Ω range.
Step 8:
Place the red probe on one leg of the resistor and the black probe on the other leg.
Step 9:
Read and record the actual value of the resistor in the space provided below:
R2 = ______________Ω.
2.4 EXPERIMENT REPORT
You will be provided with three resistors.
In each case write down the colours on the resistor, the nominal value, the range of values within
which the actual value will fall and the actual value as measured from the DMM.
CHAPTER 3 – EXPERIMENT TO VERIFY OHM’S LAW
3.0 OBJECTIVES:
You should verify that voltage and current are directly proportional to each other using a 1kΩ
resistor.
3.1 EQUIPMENT REQUIRED:





TPS – 3321
Power supply
1kΩ resistor (Color code: Brown, Black, Red, Gold)
Banana wires
Two digital multimetres (DMM)
3.2 DISCUSSION
Ohm’s law is the fundamental law of Electrical and Electronics Engineering. It relates the
current flowing through any resistor to the voltage applied to its ends. Ohm’s law states that: The
current flowing through a constant resistor is directly proportional to the voltage applied
to its ends.
Mathematically, 𝐼
𝛼𝑉
𝐼=
𝑉
𝑅
where
I is the current,
V the potential difference
and R the resistance of the constant resistor also called metallic conductor.
3.3 CIRCUIT DIAGRAM
Set up the circuit shown below:
Note: R = 1KΩ
Figure 3.1
3.4 PROCEDURE:
Step 1:
Using any of the two multimetres, read and record the actual value of the resistor
in the space provided below:
R = ______________Ω.
Step 2:
Connect the TPS – 3321 to the power supply.
Step 3:
Connect the power supply to the mains.
Step 4:
Turn ON the trainer.
Step 5:
The trainer includes a power supply module with the outlets +12V, -12V and
±12V.
The ±12V is a variable voltage outlet of this range (-12V to +12V) that can be
varied by the potentiometer.
Step 6:
Implement the circuit in figure 3.1 above using the TPS – 3321 components.
Step 7:
Put the multimetre used as an ammeter in current measuring mode, 20mA range.
Step 8:
Put the multimetre used as a voltmeter in voltage measuring mode, 20V range.
Step 9:
Adjust the power supply to produce exactly 2V across the resistor, R.
Step 10:
Read the value on the ammeter. Record this value in table 3.1 below.
Step 11:
Repeat the experiment for voltages of 4, 6, 8, 10 and 12V. Tabulate your readings.
S/N
1
2
3
4
5
6
Voltage (V)
2
4
6
8
10
12
Current (mA)
Table 3.1
3.5 GRAPH:
Plot a graph of V on the vertical axis and I on the horizontal axis.
Determine the slope, s of the graph.
3.6 EXPERIMENT REPORT
You will be provided an unknown resistor.
Set up the circuit shown below:
Measure the actual value of the resistor and record it as R.
Adjust the power supply to produce 3V across the resistor.
Measure and record the value of the current flowing through the resistor.
Repeat the procedure for voltage values of 6V, 9V, 12V and 15V.
Plot a graph of V on the vertical axis and I on the horizontal axis.
Determine the slope, s of the graph.
What physical quantity does your slope represent?
Show whether or not your values verify Ohm’s law.
CHAPTER 4 - EXPERIMENT ON INTERNAL RESISTANCE OF
VOLTAGE SOURCE
4.0 OBJECTIVES:
You should be able to:
 build a circuit consisting of a laboratory power supply.
 measure the internal resistance of the power supply.
4.1 EQUIPMENT REQUIRED:





TPS - 3321
Power supply
Multimetre
Banana wires
100Ω resistor
4.2 DISCUSSION:
The power supply is an important instrument in the electrical and electronics laboratory. It
converts an alternating current (AC) from socket in the room to direct current (DC).
An ideal voltage source produces the same voltage regardless of its load. If you short-circuit an
ideal voltage source, the current will be infinite.
From
𝐼=
𝐸
𝑅+ 𝑅𝑖𝑛
𝑅 = 0, for short circuit
𝑅𝑖𝑛 = 0, for an ideal voltage source
𝐼=
𝐸
0
=∞
There is nothing that is infinite in the real world. Therefore ideal voltage source does not exist.
Every voltage source has some value of internal resistance, usually very small. That is why
short-circuit current is very large.
Practical voltage source may be represented as an ideal voltage source with an internal
resistance:
RIN
IDEAL VOLTAGE SOURCE
Figure 4.1
Note: Ideal voltage source is frequently referred to as open-circuit voltage.
4.3 PROCEDURE:
Step 1:
Connect the TPS – 3321 to the power supply.
Step 2:
Connect the power supply to the mains.
Step 3:
Turn ON the trainer.
Step 4:
Turn ON your multimetre and put it in the voltage measuring mode at 20 V range.
Step 5:
The trainer includes a power supply module with the outlets +12V, -12V and
±12V.
The ±12V is a variable voltage outlet of this range (-12V to +12V) that can be
varied by the potentiometer.
Connect the probes of the multimetre to the ±12V and GND outlets. Adjust the
power supply to produce exactly 5V.
Step 6:
A multimetre in voltage measurement mode has a very large resistance – almost
no current flows through it. That means when only the voltmetre is connected to
the power supply, we may see it as an open-circuit state. Thus the open-circuit
voltage is now 5V.
Step 7:
Disconnect the multimetre from the power supply. Put it to the current measuring
mode, 200 mA range.
Step 8:
Implement the following circuit using TPS – 3321 components:
AMMETER
5V
100 OHMS
Figure 4.2
Write down the reading on the ammeter.
I = ___________ mA
Step 9:
Disconnect the circuit.
Step 10:
Place your DMM in the resistance measuring mode, 200Ω range. Measure the
actual resistance of the 100Ω resistor:
R = ____________Ω
Step 11:
Calculate the power supply’s internal resistance using the following formula:
𝐸
𝑅𝑖𝑛 = − 𝑅
𝐼
from
𝐼=
𝐸
𝑅+ 𝑅𝑖𝑛
( Secondary School Physics)
Step 12:
Why did we use the smallest available resistor for this measurement?
Step 13:
If we could choose the internal resistance of the power supply, which would we
choose – larger one or smaller one?
4.4 EXPERIMENT REPORT
You will be provided with a different power supply unit, a resistor and other necessary
equipment.
Using the knowledge acquired from the chapter, determine the internal resistance of the power
supply provided.
CHAPTER 5 - EXPERIMENT TO VERIFY VOLTAGE DIVIDER
THEOREM
5.0 OBJECTIVES:
The student should be able to show that voltage divider theorem holds.
5.1 EQUIPMENT REQUIRED:

TPS-3321

Power supply

A multimeter

Banana wires

Resistors: 1K, 100
5.2 DISCUSSION:
Consider figure 5.1 below:
I
R1
+
V
R2
Figure 5.1
According to voltage divider theorem, the voltage across R1 is
Similarly, the voltage across R2 is
V2 =
𝑅2
𝑅1 +𝑅2
XV
V1 =
𝑅1
𝑅1 +𝑅2
XV
5.3 PROCEDURE:
Step 1:
Connect the TPS-3321 to the power supply.
Step 2:
Connect the power supply to the Mains.
Step 3:
Turn ON the trainer.
Step 4:
Connect the +12V socket to resistor R5 at the TPS-3321.
Step 5:
Connect the free socket of R5 to resistor R6 using banana wire.
Step 6:
Connect the free socket of R6 to the minus of the power supply (the GND).
You have implemented the following circuit:
I
12V
R5
1K
R6
100
+
-
Figure 5.3
Step 7:
Turn ON the multimetre and shift it to the voltage-measuring mode, 20 Volts range.
Connect its probes to the sockets of R6. Write down the voltage you have measured:
VR6 = ________V
Step 8:
Similarly, measure voltage on the resistor R5:
VR5 = ________V
Step 9:
Measure the voltage source.
V = _________V
Step 10:
Check if:
V = VR5 + VR6
Step 11:
Check if:
𝑉𝑅5 =
Step 12:
𝑅5
𝑅5 + 𝑅6
XV
Check if:
𝑉𝑅6 =
𝑅6
𝑅5 + 𝑅6
XV
5.4 EXPERIMENT REPORT
You will be provided with a power supply unit, two resistors and other necessary equipment.
Using the procedure in this chapter, show that voltage divider theorem holds.
CHAPTER 6 - EXPERIMENT TO VERIFY KIRCHOFF'S
VOLTAGE LAW
6.0 OBJECTIVES:
The student should be able to show that Kirchoff’s Voltage Law holds.
6.1 EQUIPMENT REQUIRED:

TPS-3321

Power supply

A multimeter

Banana wires

Resistors: 5.1K, 7.5K and 10K.
6.2 DISCUSSION:
Kirchoff's Voltage Law states that The sum of all the voltages in a loop equals to zero.
Consider figure 6.1 below:
Direction of travel
Figure 6.1
Travelling from point 1 and putting the probes of the voltmeters in the same order (i.e red then
black across each of the components), the sum of the voltages across the components equals to
zero. This is Kirchoff’s Voltage Law.
6.3 PROCEDURE:
Step 1:
Connect the TPS-3321 to the power supply.
Step 2:
Connect the power supply to the Mains.
Step 3:
Turn ON the trainer.
Step 4:
Implement the circuit shown in figure 6.2 below.
R1 = 5.1 K
R2 = 10 K
12 V
R3 = 7.5 K
Figure 6.2
Step 5:
Kirchoff's Voltage Law states that The sum of all the voltages in a loop equals to
zero. Let's check this. Measure the voltage on the power supply and three resistors in
the way that voltmeter's polarity will stay constant. Write down voltages with the
sign.
V = ______________V,
VR1 = ______________V,
VR2 = ______________V,
VR3 = ______________V.
Kirchoff's Voltage Law demands that V + VR1
+ VR2 + VR3 = 0. Check that.
6.4 EXPERIMENT REPORT
You will be provided with a power supply unit, three resistors and other necessary equipment.
Using the procedure in this chapter, show that Kirchoff’s Voltage Law holds.
CHAPTER 7 - EXPERIMENT TO VERIFY KIRCHOFF'S
CURRENT LAW
7.0 OBJECTIVES:
The student should be able to show that Kirchoff’s Current Law holds.
7.1 EQUIPMENT REQUIRED:

TPS-3321

Power supply

A multimeter

Banana wires

Resistors: 5.1K, 1K.
7.2 DISCUSSION:
Kirchoff's Current Law states that The algebraic sum of all the currents entering and exiting
a node equals to zero.
Consider figure 7.1 below:
Taking the current entering the node as positive and those leaving the node as negative,
i1 + i2 + i3 = 0.
Another way to state the law is The sum of all the currents entering a node equals to the sum
of all the currents leaving the node.
7.3 PROCEDURE:
Step 1:
Connect the TPS-3321 to the power supply.
Step 2:
Connect the power supply to the Mains.
Step 3:
Turn ON the trainer.
Step 4:
Adjust the power supply variable voltage to +3V.
Step 5:
Implement the following circuit:
+
1K
R5
5.1K
R4
3V
A
Write down the measured current:
IR5 = ____mA
Step 6:
Measure the current that flows through R4:
+
1K
R5
R4
5.1K
3V
A
IR4 = ____mA
Step 7:
Measure the total current:
A
+
1K
R5
5.1K
R4
3V
-
Figure
IT = ____mA
Step 8:
Check if:
IT = IR4 + IR5
7.4 EXPERIMENT REPORT
You will be provided with a power supply unit, three resistors and other necessary equipment.
Using the procedure in this chapter, show that Kirchoff’s Current Law holds.