Small resistors use coloured painted bands which represent a number and multiplier to indicate both their resistive value and their tolerance with the physical size of the resistor indicating its wattage rating. These coloured painted bands produce a system of identification generally known as a Resistors Colour Code.
Resistor Colour Code Table
There are two resistor colour coded systems, the four-band system and the five-band system, which use coloured bands or rings that completely encircle its body to identify the resistors value. These coloured bands are usually printed towards one end of the resistors body to indicate the first digit with the colours being read from left to right.
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 giving Digit, Digit, Multiplier, Tolerance. Resistors having standard tolerance value of 20% usually do not have a fourth band.
The five-band system displays the colored bands the same as for the four-band, except for an additional third colored band to represent a third significant digit giving, Digit, Digit, Digit, Multiplier, Tolerance. The five-band system is used for high precision resistors with low tolerance.