# Rules to read the color code of carbon resistors

In Science and Engineering labs you may have seen carbon resistors. This type of resistor is usually painted with three, four, five or six bands of different colors. These bands are the codes from which one can find the value of the resistance of a resistor. Now, how to read resistor color code of carbon resistors? Go through this article and then you will never ask this question to anyone.

1. What is a Carbon resistor?
2. How to read resistor color code?
3. Resistor color code chart
4. Example of resistor color code reading

## What is a Carbon resistor and its color code?

Carbon resistors are cylindrical-shaped small metallic resistors that are commonly used in analog electronic and electrical circuits for laboratory-based works. These consist of zebra-like bands of different colors on their bodies which are the codes to find the values of resistance of the resistors.

## How to read color code of carbon resistors? all rules

To calculate the resistance of a carbon resistor, we need to read its color code. A carbon resistor may have three bands, four bands or five bands on its body. Every color refers to a digit or letter. Therefore, the color code for a resistor contains numbers and letters. In this section, we have explained the rules of resistor color code for 3, 4, 5 and 6 band carbon resistors. To calculate the resistance, follow the following rules and the resistor color code chart in the next section.

### 3 bands carbon resistor color code rule

For a three-band carbon resistor, the color code is as followings –

• First band gives the first digit (leftmost) of the resistance value
• Second band gives the second digit (from the left) of the resistance value
• Third band gives the multiplier i.e. the number of zeros after the second digit.

### 4 bands resistor color code rule

For a Four band carbon resistor, the color code is as followings –

• First band gives the first digit (leftmost) of the resistance value
• Second band gives the second digit (from the left) of the resistance value
• Third band gives the number of zeros after the second digit.
• Fourth band gives the tolerance i.e. the percentage error that the resistance value can have.

### 5 bands resistor color code rule

For a Five band carbon resistor, the color code is as followings –

• First band gives the first digit (leftmost) of the resistance value
• Second band gives the second digit (from the left) of the resistance value
• Third band gives the third digit from the left.
• Fourth band gives the multiplier i.e. number of zeros after the third digit.
• Fifth band gives the tolerance i.e. the percentage error that the resistance value can have.

### 6 bands resistor color code rule

For a six-band carbon resistor, the color code is as followings –

• First band gives the first digit (leftmost) of the resistance value.
• Second band gives the second digit (from the left) of the resistance value.
• Third band gives the third digit from the left of the resistance value.
• Fourth band of the carbon resistor gives the multiplier i.e. number of zeros after the third digit.
• Fifth band gives the tolerance i.e. the percentage error that the resistance value can have.
• Sixth band gives the temperature coefficient of the resistor.

## Resistor color code chart

Now, what will be the first and second digits of the resistance? How many zeros will be there after the second digit? These are very simple. The first three color bands on the carbon resistor indicate three numbers between 0 to 9. Similarly, some other colors represent the percentage of tolerance, multiplier and temperature co-efficient. Check the resistor color code chart for the details.

The decimal symbol is coded by the alphabet “R“.

## Example of resistor color code reading

Consider a 1500 ohm carbon resistor with 4 bands. The colors of the bands will be Brown, Green, Red and Golden. Then, the first two digits are 1 and 5 and the multiple is 100 i.e. there are two zeros after the first two digits. The fourth band of Golden color implies that the tolerance in resistance is 5%. Then the resistor color coding of 4 bands 1.5k ohm resistance is 152J.

Thus, the code 152J represents the resistance value of $\small \color{Blue}1500 \Omega \pm 5$%.

Check some other examples in detail:

Let’s practice it!

Question: Find the color code for 220 ohm and 330 ohm carbon resistors.

This is all from this article on how to calculate resistor color code of carbon resistors? Hope you understand the procedure. I advise you to take any random resistor and try to find the resistance of that resistor on your own. If you still have any doubts on this topic you can ask me in the comment section.

Thank you!

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