Department of Electrical Engineering
Faculty Member:____________________
Dated: ________________
Semester:__________________________
Section: ________________
EE-111: Linear Circuit Analysis
Lab1: INTRODUCTION TO BASIC LABORATORY EQUIPMENT
AND IDENTIFICATION OF RESISTOR COLOUR CODES
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Name
Reg. No
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Quiz / Lab
Performa
nce
5 Marks
EE-211: Electrical Network Analysis
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Analysis Modern
of data
Tool
in Lab
Usage
Report
5 Marks
5 Marks
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Ethics
and
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and Team
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Page 1
Lab1: INTRODUCTION TO BASIC LABORATORY EQUIPMENT and
IDENTIFICATION OF RESISTOR COLOR CODES
Introduction
1. The first laboratory exercise is to familiarize the students with the use of basic
laboratory equipment including the breadboard, power supply and the Digital
multi-meter (DMM). The students will be measuring the currents and voltages of the
circuits mentioned below using the DMM. To find the value of a resistor and its
tolerance by color coding and using multi-meter.
Objectives
2. The objectives of this lab are:
2.1. To use MULTIMETER as a voltmeter, Ohmmeter and Ammeter in order to
measure voltage and current respectively.
2.2. Learn the COLOUR CODES scheme to determine the values of resistances.
2.3. Learn to patch up/make simple circuits.
2.4. The student will be required to use the breadboard to plug in various resistor
combinations, calculate the expected voltages and currents and compare those
with the measured values. The differences between the calculated values and
measured values would be analyzed.
Conduct of Lab
3. The students are required to work in groups of three; each student must attempt to
understand and use the laboratory set-up and conduct at least one or two parts of
the requirement experimentation. The lab Engineer will be available to assist the
students.
4. In case some aspect of the lab experiment is not understood the students are advised
to seek help from the teacher, the lab engineer.
Lab Equipment
5. The following equipment would be used in this experiment, the students are to
familiarize themselves with the equipment before its use:
5.1. Test bench (See Annexure 1)
5.2. The Multi-meter
5.3. The Power Supply (See Annexure 2)
5.4 The Breadboard (See Annexure 1)
5.5 Resistors (See Annexure 2)
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Laboratory Experiment
PART I
DISPLAY
Familiarization with Digital Multi-meter.
Adjustment Buttons for
different parameters
The two measuring leads of the
mulltimeter. The red pin is put at the
point of higher (or +ve) potential
while the black pin is put at points of
lower (or –ve) potential.
A meter is a measuring instrument. An ammeter measures current, a voltmeter
measures the potential difference (voltage) between two points, and an ohmmeter
measures resistance. A multi-meter combines these functions and possibly some
additional ones as well, into a single instrument.
Before going in to detail about multi-meters, it is important for you to have a clear idea
of how meters are connected into circuits. Diagrams A and B below show a circuit
before and after connecting an ammeter
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to measure current, the circuit must be broken to allow the ammeter to be connected in
series. All the current flowing in the circuit must pass through the ammeter. Meters are
not supposed to alter the behavior of the circuit, or at least not significantly, and it
follows that an ammeter must have a very LOW resistance.
Diagram C shows the same circuit after connecting a voltmeter. To measure potential
difference (voltage) the circuit is not changed, the voltmeter is connected in parallel
.This time you do not need to break the circuit. The voltmeter is connected in parallel
between the two points where the measurement is to be made. Since the voltmeter
provides a parallel pathway, it should take as little current as possible. In other words, a
voltmeter should have a very HIGH resistance.
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An ohmmeter does not function with a circuit connected to a power supply. If you want
to measure the resistance of a particular component, you must take it out of the circuit
altogether and test it separately, as shown in diagram D:
Ohmmeters work by passing a small current through the component and measuring the
voltage produced. If you try this with the component connected into a circuit with a
power supply, the most likely result is that the meter will be damaged.
THE MULTIMETRE CONNECTED AS AN AMMETRE
Press the button for the
required parameter value to
be measured.
e.g Press DCA button in order
to measure the DC Current
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Red and Black Probes are
connected as shown in the
diagram, for measuring the max
current of 2A
THE MULTIMETRE CONNECTED AS THE
VOLTMETRE
Press the button for the required
parameter value to be measured.
e.g Press DCV button in order to
measure the DC Voltage
Red and Black Probes are
connected as shown in the
diagram, for measuring the max
voltage of 1000V
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MEASURING RESISTANCE WITH DMM
The button is pressed
to measure resistance.
Notice that for measuring both voltage and
resistance, the positive (red) pin is
connected in the same socket
Consider your DMM and the pictures given above. What is the range of voltage and
current that the DMM can measure?
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Range
of
V:________________________________________________________________
Range of I:_________________________________________________________________
IDENTIFICATION OF RESISTOR COLOR CODES
Theory:
Resistor values are marked onto the body of the resistor using a series of
colored bands. These give the value of the resistor as well as other information
including the tolerance and sometimes the temperature coefficient. The band closest to
the end of the resistor body is taken to be Band 1.
In case of four color bands, the first two bands are the significant figures of the
value, the third band is a multiplier (number of zeros) and fourth band is the tolerance
band, i.e. red black brown gold would be 2 0 x 10 + 5% or 200+5% ohms.
Figure : 4- band resistor
In case of five color bands first three bands are the significant figures of the
value, the fourth band is a multiplier and fifth band is the tolerance band.
Figure : 5-band resistor
In case of six color bands the sixth band is the temperature coefficient band.
Following tables give the values allocated to different colors to find the value of a
resistor through the color bands it has on it.
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5-band Resistor Color Codes:
Color
Band 1
Band 2
Band 3
Multiplier
Black
0
0
0
1
Brown
1
1
1
10
Red
2
2
2
100
Orange
3
3
3
1000
Yellow
4
4
4
10000
Green
5
5
5
100000
Blue
6
6
6
1000000
Violet
7
7
7
10-1
Grey
8
8
8
10-2
White
9
9
9
The resistance value of the resistor is not the only thing to consider when selecting a
resistor for use in a circuit. The "tolerance" and the electric power ratings of the resistor
are also important. The tolerance of a resistor denotes how close it is to the actual rated
resistance value. For example, a ±5% tolerance would indicate a resistor that is within
±5% of the specified resistance value.
Tolerance:
Color:
None
Tolerance: 20%
Silver
Gold
Red
Brown
10%
5%
2%
1%
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Lab Exercise:
Select three resistors (5% tolerance) between 1Ω and 1MΩ. Verify the value of
resistance and tolerance of resistors using color codes, and complete the following table:
No. Value of
Resistance
through color
codes (Ω)
Tolerance Value of
(%)
Resistance
measured by the
DMM (Ω)
Error
(%)
1.
2.
3.
The circuits for this lab report are designed using simulation software. The
following legend details the symbols used to represent different electronic
equipment.
Legend
Resistance
Power supply
Multimeter
Connecting Wires
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PART II
MEASUREMENTS USING DMM
Simple Circuit using a known resistor / resistors
FIGURE 1
I.
Calculate the current passing through the resistor R1 (known as IR1), power
absorbed by resistor R1 (PR1) and the power delivered by the source (PS).
IR1:____________________________________________________
PR1:____________________________________________________
PS:____________________________________________________
II.
Now connect the DMM as voltmeter in order to measure the voltage in the
circuit as shown in the configuration below. Here the voltmeter is shown
connected across points B and C. To measure voltage across a different set of
points you will have to disconnect the voltmeter and connect it between the
desired points. Fill in the required results in Table 1.
FIGURE 2a
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Now connect the DMM as ammeter in order to measure the current in the
circuit as shown in the configuration on the following page. Here the
ammeter is shown connected between points A and B. To measure current at
different points you shall have to disconnect the ammeter and connect it
between the desired points. Fill in the required results in Table 1
FIGURE 2b
SNo
Value
1
Voltage A-B
2
Voltage B-D
3
Voltage A-C
4
Current C-D
Calculated
Measured
Difference
5
Current A-B
TABLE 1
Comment on any variations observed between the measured and the calculated values
of the voltages and currents.
______________________________________________________________________________
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______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
Vary the voltage from 0 to 5 V in 5 steps of 1V each and note down the values of voltage
and current. Use these values to plot a graph below. From the slope of the graph
calculate the resistance and compare against the given value.
Value of R: ____________________________________________________
%age Deviation: __________________________________________________________
_________________________________________________________________________
III.
Repeat the method employed in part II for the following configurations and note
down the results in the table 2.
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FIGURE 3a
SNo
Value
1
Voltage A-B
2
Voltage C-D
3
Voltage B-C
4
Current A-B
5
Current B-C
Calculated
Measured
Difference
TABLE 2
Comment on any variations observed between the measured and the calculated values
of the voltages and currents.
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
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In your own words, summarize what you have learned in the lab and explain any
difficulties you encountered.
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
EE-211: Electrical Network Analysis
Page 15
EE-109: Linear Circuit Analysis & EE-113: Engineering Circuit Analysis-I
Page 16
NODES OF A BREADBOARD
THE HORIZONTAL
NODES
The Vertical
Nodes
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ANNEXURE 2
RESISTORS
CONNECTED IN SERIES
WITH POWER SUPPLY
ACROSS THEM
RESISTORS IN PARALLEL WITH
POWER SUPPLY ACORSS THEM
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THE POWER SUPPLY IS SET TO DELIVER A VOLTAGE OF 4.9Volts
NOTICE THAT THE CURRENT KNOB IS TURNED A LITTLE UP. IF IT WERE SET TO ZERO, THE
POWER SUPPLY WOULD NOT SUPPLY ANY VOLTAGE
DISPLAY
EE-111: Linear Circuit Analysis
Voltage
Knob
CURRENT
KNOB
Page 19
TWO RESISTORS CONNECTED IN SERIES AND PARALLEL
Notice that the left end of
the 1st resistor is
connected at node #7
while the right end is
connected at node #16 and
the left hand end of the 2nd
resistor is connected at
node #16 and the right end
at node #28. Hence the
resistors share one
common node i.e. node
#16.
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