This article contains Resistor colour coding experiment. Lab Work. There are 5 given resistors as sample & we need to find its value, by reading colour bands on it.
Aim of the experiment
Resistor colour coding
Objective
- To learn resistor colour coding.
- To determine the stated value of a resistor by interpreting the colour code indicated on the resistor.
Apparatus Required
The Apparatus required for resistor colour coding are –
- Carbon resistor ( Sample )
- Digital Multi meter
Theory
There are two ways to find the resistor value. The colour bands on the body of resistor tell how much resistance it has. As shown in the following diagram figure. There are 5 band resistor and 4 band resistor. From both five and four band resistor, the last band indicates tolerance. Even if the values are printed, the letters will be so small that it would be difficult to read them by naked eyes. Therefore, the colour bands are printed on the resistor. This system of representing the value of resistor is known is colour coding.
Resistor Colour Coding Table
The Colour band sequence | ||||
Colour | 1st band | 2nd band | Multiplier | tolerance |
Black | 0 | 0 | 0 | _ |
Brown | 1 | 1 | 10 | _ |
Red | 2 | 2 | 102 | _ |
Orange | 3 | 3 | 103 | _ |
Yellow | 4 | 4 | 104 | _ |
Green | 5 | 5 | 105 | _ |
Blue | 6 | 6 | 106 | _ |
Violet | 7 | 7 | 107 | _ |
Grey | 8 | 8 | 108 | _ |
White | 9 | 9 | 109 | _ |
Gold | – | – | ± 5% | |
Silver | – | – | ± 10% | |
No Colour | – | – | ± 20% | |
Procedure
Procedure for Resistor colour coding.
- Axial resistors are cylindrical and have leads extending from each end.
- Look at the resistor so the group of three or four colour band are on the left side.
- Read the bands colour from left to right.
- The value of resistor colour code system is recorded.
- In other way, the central Knob of digital multimeter is adjusted to get the appropriate measurement value.
- The value of resistor shown in digital multimeter is recorded.
Calculation
Analysed Data for given sample resistors is noted below –
- First resistor
Band | colour | Significant digit |
1st band | Green | 5 |
2nd band | Blue | 6 |
Multiplier | Red | 102 |
Tolerance | Gold | ± 5 % |
Theoretical value
= 56 X ± 5 % Ω = 5600 ± 5 % Ω
= 5.6 kΩ ± 5 %
Upper value | Lower value |
5600 + 5600 * 5 / 100 | 5600 – 5600 * 5 / 100 |
5880 Ω = 5.880 kΩ | 5320 = 5.320 kΩ |
Practical Value = 5.57 kΩ ( Verified using multi meter )
- Second Resistor
Band | Colour | Significant digit |
1st band | Brown | 1 |
2nd band | Green | 5 |
Multiplier | Red | 102 |
Tolerance | Gold | ± 5 % |
Theoretical value
= 15 * Ω ± 5% = 1500 Ω ± 5 %
= 1.5 kΩ ± 5 %
Lower value | Upper value |
1500 – 1500 * 5 / 100 | 1500 + 1500 * 5 / 100 |
1425 Ω | 1575 Ω |
1.425 Ω | 1.575 kΩ |
Practical Value = 1.46 kΩ ( measured using multi meter )
- Third resistor
Band | Colour | Significant digit |
1st band | Red | 2 |
2nd band | Red | 2 |
Multiplier | Brown | 10 |
Tolerance | Gold | ±5% |
Theoretical Value
= 22 * 10 Ω ± 5 % = 220 Ω ± 5 %
= 0.22 kΩ ± 5 %
Upper value | Lower value |
220 + 220 * 5 / 100 | 220 – 220 * 5 / 100 |
( 220 + 11 ) Ω | ( 220 – 11 ) Ω |
231 Ω | 209 Ω |
Practical value = 215 Ω ( measured using multi meter )
- Fourth Resistor
Band | Colour | Significant digit |
1st band | Yellow | 4 |
2nd band | Blue | 6 |
Multiplier | Orange | |
Tolerance | Gold | ± 5 % |
Theoretical value
= 46 * Ω ± 5 % = 4600 Ω ± 5 %
= 46 kΩ ± 5 %
Upper value | Lower value |
46000 + 46000 * 5 / 100 | 46000 – 46000 * 5 / 100 |
46000 + 2300 | 46000 – 2300 Ω |
48300 Ω = 48.3 kΩ | 43700 = 43.7 kΩ |
Practical Value = 47.1 kΩ ( measured using multi meter )
- 5th resistor
Band | Colour | Significant digit |
1st band | Brown | 1 |
2nd band | Green | 5 |
Multiplier | Orange | |
Tolerance | Gold | ±5% |
Theoretical Value
= 15 * Ω ± 5 % = 15000 Ω ± 5 %
= 15 kΩ ± 5 %
Upper value | Lower value |
15000 + 15000 * 5 / 100 | 15000 – 15000 * 5 / 100 |
15000 + 750 | 15000 – 750 Ω |
15750 Ω = 15.750 kΩ | 14250 = 14.250 kΩ |
Practical value = 14.20 kΩ ( measured using multi meter )
Observation Table
1st | 2nd | 3rd
| total | T V kΩ | L V | U V | P V |
Green 5 | Blue 6 | Red | Gold ±5% | 5.6 kΩ | 5.32 kΩ | 5.88 kΩ | 5.57 kΩ |
Brown 1 | Green 5 | Red | Gold ±5% | 1.5 kΩ | 1.5 kΩ | 1.425 kΩ | 1.46 kΩ |
Red 2 | Red 2 | Brown | Gold ±5% | 220 Ω | 209 Ω | 231 Ω | 215 Ω |
Yellow 4 | Blue 6 | Orange | Gold ±5% | 46 kΩ | 43.7 kΩ | 48.3 kΩ | 47.1 kΩ |
Brown 1 | Green 5 | Orange | Gold ±5% | 15 kΩ | 14.25 kΩ | 15.75 kΩ | 14.30 kΩ |
Conclusion
As a conclusion, the resistor colour code was very useful in determining the value of individual resistor, The represented data in the table indicate that all the resistor selected were within the tolerance range specified by the colour code. The value of resistor from digital multi meter got matched by the manual calculation using colour code.
Author
Akash Sharma
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