High School Physics

How to find resistance using Resistor Colour Codes

Small resistors use coloured or painted bands which represent their resistive value and tolerance. These coloured painted bands produce a system of identification generally known as a Resistors Colour Code. The physical size of the resistor indicates its wattage rating.

Resistor Colour Code Table

There are two types of resistor colour coding systems, the four-band system and the five-band system. These systems use coloured bands or rings that completely encircle the resistor body to represent the value of the resistors.

Now here is the colour code table for resistors. This table helps to retrieve the digit, multiplier and tolerance values of the selected colours and to derive the resistance value and tolerance of a given resistor.

These coloured bands are usually printed towards one end of the resistor body to indicate the first digit with the colours being read from left to right.

Resistor Colour Code Table
Resistor Colour Code Table

four-band system of resistor color coding – how to use?

In the four-band system, the first band closest to the edge represents the first digit of the resistance value, the second band is the second digit, the third band is the decimal multiplier, which tells us how many zeros to add after the first two digits and the fourth band is the tolerance. Thus the 4 bands of this colour coding system provide information in this sequence: Digit, Digit, Multiplier, Tolerance. Resistors having a standard tolerance value of 20% usually do not have a fourth band.

five-band system of resistor color coding – how to use?

The five-band system displays the coloured bands the same as for the four-band, except for an additional third coloured band to represent a third significant digit. Thus the 5 band colour coding system provides information in this sequence: Digit, Digit, Digit, Multiplier, Tolerance.

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The five-band colour coding system is used for high precision resistors with low tolerance.

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