ECE 101
AS
Exploring Electrical Engineering
LAB 1
PSU
ECE 101 Lab 1
Note: All team members shall receive identical credit for the same lab. A report includes: 1.) lab
subject, 2.) names of all team members, 3.) date, 4.) the PSU term information, 5.) lab goal, 6.)
detailed findings of lab project; this is the main body of the report, 7.) summary and conclusion,
and 8.) signatures of all team members. Lab reports should be composed on one page max or
less, if possible. To receive credit for lab 4, all team members need to be personally in the lab
with the TA at the same time.
If all 4 simple lab experiments are conducted sequentially during a single, long meeting in the
Tektronix lab, the four reports may all be grouped together and require only one signature each
by all team members, and also by the TA to render the grade official
Objective:
1) To study the color code of resistors and to understand how the resistor value and its tolerance
are represented.
2) To practically study the color rings on resistors and read resistance and tolerance of various
resistors values using color code.
3) To measure the actual value of resistance using multimeter (ohm meter) and compare the
actual
value of resistance with the nominal value. Analyze how much the actual value of the resistance
is
deviated from the nominal value with respect to the tolerance specified.
4) To study the color code of capacitors and to understand how the capacitor value is
represented.
Equipment: Assorted resistors, cables, wires and multimeter
Introduction:
A resistor is an electric element made intentionally to obtain a fixed value resistance property.
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ECE 101
AS
Exploring Electrical Engineering
LAB 1
PSU
Figure 1: Resistors with color bands
A resistor is the device, while the resistance is the property of resisting the current flow. Any
element may have a resistance not only a resistor. It is a 2 terminal component (see figure 1). The
2 terminals are equivalent; you can connect it in one direction or the other. The resistance value,
tolerance, and wattage rating are generally printed onto the body of the resistor as numbers or
letters when the resistors body is big enough to read the print, such as large power resistors. But
when the resistor is small such as a 1/4W carbon or film type, these specifications must be shown
in some other manner as the print would be too small to read. So to overcome this, in small
resistors we use color bands to indicate both their resistive value and their tolerance with the
physical size of the resistor indicating its wattage rating. These colored painted bands produce a
system of identification generally known as a Resistors Color Code.
An international and universally accepted Resistor Color Code Scheme was developed many
years ago as a simple and quick way of identifying a resistors ohmic value, no matter what its
size or condition is. It consists of a set of individual colored rings or bands in spectral order
representing each digit of the resistors value (see figure. 2).
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ECE 101
AS
Exploring Electrical Engineering
LAB 1
PSU
Figure. 2: Resistor with color rings
The resistor color code markings are always read one band at a time starting from the left to the
right, with the larger width tolerance band oriented to the right side indicating its tolerance. The
1st and the 2nd color bands represent 2 digits of the value, the 3rd color band represents power
of 10 multiplicand, the 4th color band represents the tolerance. Tolerance indicates how much
the measured value of its actual resistance is different from its nominal (indicated/ theoretical)
value, and it is calculated using percentages.
1) To study the color code of resistors and to understand how the resistor value and its
tolerance are represented.
Procedure:
i) Refer the international color code table T.1.1 and observe the table carefully to try to
understand how colors are indicated to represents the resistance and tolerance value. Generally,
the resistors are represented by four bands of colors. The 1st and the 2nd color bands represent 2
digits of the value, the 3rd color band represents 10 multiplicand, the 4th color band represents
the tolerance. The Precision resistors are sometimes represented by 5 or 6 bands of color where
the 3rd band represent 3rd digit, 4th band represent 10 multiplicand, 5th band represent tolerance
and 6th band represent temperature coefficient.
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ECE 101
AS
Exploring Electrical Engineering
LAB 1
PSU
Table: T.1.1 International color code table.
ii) Refer Figure 3 below and observe carefully. In this figure, examples resistors 4 bands, 5 bands
and 6 bands of colors are shown and indicated how the nominal values of resistors are to be read.
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ECE 101
AS
Exploring Electrical Engineering
LAB 1
PSU
Figure 3: Resistors with 4 bands, 5 bands and 6 bands of color code.
2) To practically study the color rings on resistors and read the resistance and tolerance
values of various resistors using color code.
Procedure
i) Take some assorted resistors available in laboratory. Hold a resistor in your hand and read the
color rings (bands) by referring to table T.1.1.
ii) Read the color rings/bands on the resistors left to right one by one and record the ring color
and its value in the table T 1.2 shown below. Note down the Nominal resistance value (R
Nominal ) and tolerance of the resistor in the table.
iii) Repeat the above procedure for few more resistors.
iv) Write down your observation.
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ECE 101
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Exploring Electrical Engineering
LAB 1
PSU
1st color
2nd color
3rd color
4th color
5th color
band
band
band
band
band
colo
valu
colo
valu
r
e
r
e
colo
r
valu
e
colo
valu
colo
valu
r
e
r
e
Resistanc Tolerance
e
in
Value
Percentag
(R Nominal)
e
in Ohms
Resisto
r1
Resisto
r2
Resisto
r3
Resisto
r4
Resisto
r5
Resisto
r6
Table T.1.2 : Recorded values of resistor color bands and its Nominal value
3) To measure the actual value of resistance using multimeter (ohm meter) and compare
the actual value of resistance with the nominal value. Analyze how much the actual value of
the resistance deviated from the nominal value with respect to the tolerance specified.
Procedure:
i) Write down for each resistor, the Nominal resistance value (R Nominal) and its tolerance as
recorded in the experiment 2 of table 1.2 above in the table T.1.3.
ii) Take a multi meter, put the selector in resistance mode and select the proper range of
resistance value to be measured on the meter. For example, to measure the resistance of ohms
few Ohms select the meter range say 100 Ohms, for few hundred Ohms select range 1K Ohms,
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ECE 101
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Exploring Electrical Engineering
LAB 1
PSU
to measure few Kilo Ohms select range 10K Ohms, and to measure few tens of Kilo Ohms select
100K Ohms, and few Hundred Kilo Ohms select 1M Ohms range.
iii) After selecting the range, using the a multi meter probes practically measure the actual value
of the resistors earlier recorded using color code and tabulate the actual values of resistance (R
actual) measured one by one in the table T.1.3.
Resistance
Value (R Nominal)
in Ohms as per
color code
Indicated
Tolerance
in
Percentage
Measured
Actual value
of the
resistance
( R Actual ) in
Ohms
Remark
Resistor
1
Resistor
2
Resistor
3
Resistor
4
Resistor
5
Resistor
6
Table T.1.3: Indicates R Nominal and R Actual Resistance values
iv) Using the following equation, for the indicated tolerance for each resistor, verify whether
actual value of the resistance R actual measured lies within the tolerance range. Analyze the
result and make your comment on the resistance value in the remark column.
{Rnominal - Rnominal (Tolerance/100) } ≤ Ractual ≤ {Rnomina l + Rnominal
(Tolerance/100)}
v) Write a brief report about components analyzed.
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ECE 101
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Exploring Electrical Engineering
LAB 1
PSU
4) To study the color code of capacitors and to understand how the capacitor value is
represented.
Components: Various types of capacitors like Dipped Tantalum Capacitors, Mica Capacitors
and Polyester/Polystyrene Capacitors of different values.
Procedure:
i) Refer the international color code tables T.1.4, T.1.5 and T.1.6 and observe the table carefully
to try to understand how colors are indicated to represents the capacitance, tolerance and voltage
values. Generally, the capacitors are represented by four bands of colors similar to that of
resistors.
Capacitor Color Codes:
Generally, the actual values of Capacitance, Voltage or Tolerance are marked onto the body of
the capacitors in the form of alphanumeric characters. However, when the value of the
capacitance is of a decimal value problems arise with the marking of the “Decimal Point” as it
could easily not be noticed resulting in a misreading of the actual capacitance value. Instead
letters such as p (pico) or n (nano) are used in place of the decimal point to identify its position
and the weight of the number.
For example, a capacitor can be labelled as, n47 = 0.47nF, 4n7 = 4.7nF or 47n = 47nF and so on.
Also, sometimes capacitors are marked with the capital letter K to signify a value of one
thousand pico-Farads, so for example, a capacitor with the markings of 100K would be 100 x
1000pF or 100nF.
To reduce the confusion regarding letters, numbers and decimal points, an International colour
coding scheme was developed many years ago as a simple way of identifying capacitor values
and tolerances. It consists of colored bands (in spectral order) known commonly as the Capacitor
Color Code system and whose meanings are illustrated below:
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ECE 101
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Exploring Electrical Engineering
LAB 1
PSU
Capacitor Color Code Table
Temperature
Coefficient
(TC)
Band
Colour
Digit
A
Digit
B
Multiplier
D
Tolerance
(T) > 10pf
Tolerance
(T) < 10pf
Black
0
0
x1
± 20%
± 2.0pF
Brown
1
1
x10
± 1%
± 0.1pF
-33×10-6
Red
2
2
x100
± 2%
± 0.25pF
-75×10-6
Orange
3
3
x1,000
± 3%
-150×10-6
Yellow
4
4
x10,000
± 4%
-220×10-6
Green
5
5
x100,000
± 5%
Blue
6
6
x1,000,000
Violet
7
7
Grey
8
8
x0.01
+80%,-20%
White
9
9
x0.1
± 10%
Gold
x0.1
± 5%
Silver
x0.01
± 10%
± 0.5pF
-330×10-6
-470×10-6
-750×10-6
TABLE T.1.4
9
± 1.0pF
ECE 101
AS
Exploring Electrical Engineering
LAB 1
PSU
Voltage Rating (V)
Band
Colour
Type J
Type K
Black
4
100
Brown
6
200
100
1.6
Red
10
300
250
4
Orange
15
400
Yellow
20
500
Green
25
600
Blue
35
700
Violet
50
800
Grey
White
3
Gold
Type L
Type M
Type N
10
10
35
40
400
6.3
6
16
15
630
20
900
25
25
1000
2.5
3
2000
Silver
Table T.1.5
Capacitor Voltage Reference
• Type J – Dipped Tantalum Capacitors.
• Type K– Mica Capacitors.
• Type L– Polyester/Polystyrene Capacitors.
• Type M– Electrolytic 4 Band Capacitors.
• Type N– Electrolytic 3 Band Capacitors.
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ECE 101
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Exploring Electrical Engineering
LAB 1
PSU
Metalised Polyester Capacitor
Disc & Ceramic Capacitor
The Capacitor Color Code system was used for many years on unpolarised polyester and mica
molded capacitors. This system of color coding is now obsolete but there are still many “old”
capacitors around. Nowadays, Small Capacitors such as film or disk types conform to the BS1852
Standard and its new replacement, BS EN 60062, were the colors have been replaced by a letter or
number coded system. Generally, the code consists of 2 or 3 numbers and an optional tolerance letter
code to identify the tolerance. Where a two number code is used the value of the capacitor only is
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ECE 101
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Exploring Electrical Engineering
LAB 1
PSU
given in picofarads, for example, 47 = 47 pF and 100 = 100pF etc. A three letter code consists of the
two value digits and a multiplier much like the resistor color codes in the resistors section.
For example, the digits 471 = 47*10 = 470pF. Three digit codes are often accompanied by an
additional tolerance letter code as given below.
Capacitor Letter Codes Table
Picofarad
Nanofarad Microfarad
(pF)
(nF)
(uF)
10
0.01
0.00001
15
0.015
22
Picofarad
Code
Nanofarad Microfarad
Code
(pF)
(nF)
(uF)
100
4700
4.7
0.0047
472
0.000015
150
5000
5.0
0.005
502
0.022
0.000022
220
5600
5.6
0.0056
562
33
0.033
0.000033
330
6800
6.8
0.0068
682
47
0.047
0.000047
470
10000
10
0.01
103
100
0.1
0.0001
101
15000
15
0.015
153
120
0.12
0.00012
121
22000
22
0.022
223
130
0.13
0.00013
131
33000
33
0.033
333
150
0.15
0.00015
151
47000
47
0.047
473
180
0.18
0.00018
181
68000
68
0.068
683
220
0.22
0.00022
221
100000
100
0.1
104
330
0.33
0.00033
331
150000
150
0.15
154
470
0.47
0.00047
471
200000
200
0.2
254
560
0.56
0.00056
561
220000
220
0.22
224
680
0.68
0.00068
681
330000
330
0.33
334
750
0.75
0.00075
751
470000
470
0.47
474
820
0.82
0.00082
821
680000
680
0.68
684
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ECE 101
AS
Exploring Electrical Engineering
LAB 1
PSU
1000
1.0
0.001
102
1000000
1000
1.0
105
1500
1.5
0.0015
152
1500000
1500
1.5
155
2000
2.0
0.002
202
2000000
2000
2.0
205
2200
2.2
0.0022
222
2200000
2200
2.2
225
3300
3.3
0.0033
332
3300000
3300
3.3
335
ii) Write a brief report about how you analyzed the capacitors’ color code.
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