How to read resistor values (Beginners, 2024)

A Resistor is a fundamental component in electronics, which allows us to control the flow of current and voltage levels.

Most resistors have four or five color bands, each representing numbers. In a four-band resistor, the first two bands are digits, the third is the multiplier (power of ten), and the fourth is for tolerance, indicating how much the actual resistance can vary. For a five-band resistor, the first three bands represent digits, the fourth is the multiplier, and the fifth is for tolerance.

In this article, we will provide a comprehensive guide on how to read resistor values, covering the color code method.

Resistor value reading

A resistor is a passive two-terminal component that opposes the flow of current. This component is designed in such a way that it controls the amount of current in the circuit.

In other words, we can say a resistor is a component that offers resistance. The resistance of a resistor is measured in ohms (Ω). The color code or numerical values printed on the resistors represent the resistance value.

The resistors come in various shapes, types, and sizes. The two types of resistors are fixed and variable resistors.

They are used in circuits for voltage division, current limiting, signal controlling, and temperature settings.

If you want to learn about resistors, check out our article:

Resistor basics for beginners

How to read resistor values?

To design an electronic circuit, you need resistors with different values of resistance, you need to learn how to read resistor values.

Resistors are really small and thin in size so it is very difficult for manufacturers to print their value on it.

So instead of the resistance value, they print different color bands on them.

Color	Digit	Multiplier	Tolerance
Black	0	1
Brown	1	10	± 1%
Red	2	100	± 2%
Orange	3	1000
Yellow	4	10000
Green	5	100000	± 0.5%
Blue	6	1000000	± 0.25%
Violet	7	10000000	± 0.1%
Grey	8	100000000	± 0.05%
White	9	1000000000
Gold		0.1	± 5%
Silver		0.01	± 10%

Resistor Color code table

Step-by-step reading of resistor values

Let’s discuss the step-by-step process of how to read resistor values in detail for your better understanding.

1. Identify the resistor

The first step is to locate the resistor and see that its color bands are neat and clear. This is a crucial step as the color bands are responsible for the correct identification of resistor value.

2. Count the color bands

Some resistor has four bands and some have five bands. To read the value it is important to know how many bands resistors have.

In four-band resistors, the first two bands represent the first and second digits of the resistor and the third band is mutilper which is the power of ten by which to multiply the first two digits. The fourth band is for tolerance.

The start color bands of a resistor are closer to each other while the tolerance band has distance from each other so always identify these bands and start reading from left to right.

For five-band resistors, the first three colors represent the digits of a resistor, the fourth one is for multiplier and the fifth one is for tolerance.

3. Assign the numbers to colors

Now in this step, you have to assign the number to the band colors that are mentioned in the above table. Each color shows a specific number. For a better understanding, let’s look at the examples.

First, we have a four-band resistor, the first and second colors are blue which has a value of 6, the third color is brown which has a multiplier value of 10, and the fourth is green color which represents tolerance and its value is ± 0.5%.

So the value of the above resistor is 660Ω with ± 0.5% tolerance. The tolerance means the resistor value is in the 656.7 to 663.3Ω range.

In a five-band resistor, we have five colors. The above example has brown, green, and red as digits color and their values are 1, 5, and 2 respectively.

The multiplier has a black color that has a value of 10^0 which is equal to 1. The tolerance band has a gold color so the resistor has ± 5% tolerance.

The above resistor has a value of 152Ω with ± 5% tolerance. The value can also be written as 152Ω, ± 5%. The actual value of the resistor will be in the range of 144.5 to 159.6Ω.

These are the steps that will help you to read resistor values correctly and efficiently.

Precautions

There are a few things to take into account to ensure appropriate interpretation when determining a resistor’s value from its color bands:

Ensure that the color bands of resistors are not faded or damaged.
Differentiating between similar colors like brown and red or blue and violet is crucial for correct interpretation. Take a close look at these colors for proper interpretation.
Understand the sequence in which the bands are read for both four-band and five-band resistors.
Always start reading from left to right.
Make sure to read the bands from the correct starting point to avoid errors.
Recognized the tolerance band efficiently and correctly to avoid any error in resistor value reading.

For better and more accurate reading of resistor value, the above points should be considered while calculating resistor value.

Conclusion

For anyone working with electronics or tackling electronic circuits, reading the resistor’s values is an essential skill.

The color code method is used broadly for reading the resistor values. By understanding the color code, you can accurately determine the resistance value and tolerance of resistors.

The resistor has a different number of bands. For the four bands, the first two color bands show the digits, third and fourth ones represent multiplier and tolerance respectively.

In five bands, the first three bands represent digits, the fourth one is for multiplier and the fifth one is for tolerance.

When you look at the resistor, it always has some band colors closer to each other and some are at a distance.

First, identify the closer bands and start giving the color code to it from left to right. This is how you will read the values of various resistors.

This was all about how to read resistor values using the color codes of the resistor. I hope it will be helpful.

Thank you and stay blessed…