Resistor colour coding | lab work

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

1. To learn resistor colour coding.
2. 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 –

1. Carbon resistor ( Sample )
2. 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.

1. Axial resistors are cylindrical and have leads extending from each end.
2. Look at the resistor so the  group of three or four  colour band  are on the  left side.
3. Read the bands colour from left to right.
4. The value of resistor colour code system is recorded.
5. In other way, the central Knob of digital multimeter is adjusted to get the appropriate measurement value.
6. The value of resistor shown in digital multimeter is recorded.

Calculation

Analysed Data for given sample resistors  is noted below –

1. 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 )

2. 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 )

3. 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 )

4. 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 )

5. 5^th 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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