Resistor Colour Code

Resistor are two terminal devices that are important components of any electronic device. Resistors are used in an electronic circuit to regulate the flow of the electric current in the electric circuit. The resistor commonly used by us are printed in different colours. A typical resistor usually contains four colour bands and these colour bands usually tell the value of the resistor reading these colour codes is very important for building even the very basic electric circuit.

In this article, we will learn about, Resistance Colour Code, How to Read Resistor Colour Code, Examples to Find Resistance Colour Code, and others in detail.

Resistor Colour Code

The value of resistance offered by a resistor is marked using a colour code called Resistor Colour Code. The resistors we use are very tiny and the printing of the value of resistance in the resistor is not feasible. Thus, to find the value of the resistor we use various colour bands(mainly four colour bands) that help to determine the value of the resistance. These colour bands on the resistor are called the Resistor Color Codes. This Resistor Colour Code was invented by the Radio Manufacturers Association (RMA) in the 1920s.

The image added below shows a resistor along with the colour bands of the resistor.

All the resistors used in modern circuits up to one watt are colour coded with different bands. There are a set of three to six bands but majorly resistors have a set of four bands marked on the resistance and they tell us the value of the resistance. In the colour-coding sequence, the first two bands indicate the resistance value and the third band serves as the multiplier for the two bands. 

Resistor Colour Table

The table added below shows different colours added to the resistor and their respective values.

Colour	Colour Representation	Digit	Multiplier	Tolerance
Black		0	1
Brown		1	10	± 1%
Red		2	100	± 2%
Orange		3	1000
Yellow		4	10,000
Green		5	100,000	± 0.5%
Blue		6	1,00,000	± 0.25%
Violet		7	10,000,000	± 0.1%
Grey		8		± 0.05%
White		9
Gold			0.1	± 5%
Silver			0.01	± 10%

How to Read Resistor Colour Code?

The colour code in any resistor is read as, in general, a resistor has four bands in which the first two bands represent the value of the resistance and the third band represent the resistance multiplier whereas, the fourth and the last band represent the tolerance of the resistance. For reading any resistance we hold the resistor in such a way that its tolerance band is to our right. generally, the tolerance is silver and gold in colour and it is at a distance from the other band.

Now starting from our left, mark all the colours of the bands and write them down in sequence. Then, use the table given above to see which digits they represent.

The third band is the multiplier band and the colour represents the 10 multiplier. Such as if the third band is green then its value is 10⁵. 

Example of Resistor Colour Coding

The resistor colour coding is used to determine the value of the resistance of the electrical resistor. This can be understood using the example discussed below as, 

The image added below shows resistance and using resistor colour coding determines its resistance value.

The band colours for the resistor colour code in the order:

Band colours in order RED ORANGE ORANGE GOLD

Using the table the digit representation is as 2 2 3 with multiplier 10³ and the tolerance ±5%

Thus, the value of the resistance is, 23×10³ Ω ± 5 %

i.e. the value of the resistance is, 23000 Ω ± 5 %

The value of the given resistance is:

23000 Ω ± 5 %. The tolerance of the resistor can be calculated as follows:

Tolerance = Value of Resistor × Value of Tolerance Band

=  23000 Ω ⨯ 5 % = 1150 Ω

This means that the 23000 Ω resistor with a tolerance value of 1150 Ω could range from the actual value as much as 24150 Ω to as little as 22850 Ω. 

Mnemonic of Resistor Colour Code

Learning the Resistor Colour Coding is very important and the mnemonic used to find the value of the resistor is,

BB ROY of Great Britain had a Very Good Wife

The capital letters represent the first letters of the colours and their positions in the digit values. The representation of the colour code as,

Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, and White

Read More,

• Electrical Resistance
• Equivalent Resistance
• Resistivity

Resistor Colour Code Examples

Example 1: Find the resistance of the resistor

Solution:

The band colours for resistor colour code in the order:

Band colours in order RED RED ORANGE SILVER

using the table the digit representation is as, 2 2 3 and the tolarence is ±10%

Thus, the value of the resistance is, 22×10³ Ω ± 10 %

i.e. the value of the resistance is, 22000 Ω ± 10 %

The value of the given resistance is:

22000 Ω ± 10 %. The tolerance of the resistor can be calculated as follows:

Tolerance = Value of Resistor × Value of Tolerance Band

=  22000 Ω ⨯ 10 % = 2200 Ω

This means that the 22000 Ω resistor with a tolerance value of 2200 Ω could range from the actual value as much as 19800 Ω to as little as 24200 Ω. 

Example 2: Find the resistance of the resistor,

Solution:

The band colours for resistor colour code in the order:

Band colours in order ORANGE RED BLACK SILVER

using the table the digit representation is as, 3 2 1 and the tolarence is ±10%

Thus, the value of the resistance is, 32×10¹ Ω ± 10 %

i.e. the value of the resistance is, 32 Ω ± 10 %

The value of the given resistance is:

32 Ω ± 10 %. The tolerance of the resistor can be calculated as follows:

Tolerance = Value of Resistor × Value of Tolerance Band

=  32 Ω ⨯ 10 % = 3.2 Ω

This means that the 32 Ω resistor with a tolerance value of 3.2 Ω could range from the actual value as much as 28.8 Ω to as little as 35.2 Ω. 

FAQs on Resistor Colour Code

Q1: Why are Resistors Colour Coding done?

Answer:

Resistor are very small electronic devices and it is very difficult to print values on the resistor and so we use colour bands to represent the value of the electrical resistance. 

Q2: How does Resistor Colour Code work?

Answer:

There are various bands of colour added to the resistor that are used to represent the values of the resistance, generally a resistor has three to six bands. In general, for a resistor with five bands the first three bands represent the significant digits, the fourth band is the multiplying factor and the fifth band represents the tolerance.

Q3: What is the Trick to Remember Resistor Colour Code?

Answer:

We use the mnemonics to learn the Resistor Colour Code as, 

“BB ROY of Great Boy had a Very Good Wife,” the capital letters represent the first letters of the colours and their positions in the digit values, i.e. Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, and White.

Q4: What is Colour Code of a Resistor?

Answer:

A resistor with a colour code is used to represent the value of the resistor. In a resistor with five bands, the first three bands indicate the significant digits, the fourth band is the multiplication factor, and the fifth band represents the tolerance.

Q5: Who Invented Resistor Colour Code?

Answer:

The Resistor Colour Code was developed by the Radio Manufacturers Association (RMA) in the 1920s.