Carbon resistors are small in size and hence their values are given using a color code.
The resistors have a set of co-axial colored rings on them whose significance are listed in Table.
The first two bands from the end indicate the first two significant figures of the resistance in ohms.
The third band indicates the decimal multiplier.
The last band stands for tolerance or possible variation in percentage about the indicated values.
Sometimes, this last band is absent and that indicates a tolerance of 20%.
For example, if the four colors are orange, blue, yellow and gold, the resistance value is 36 × 104 Ω, with a tolerance value of 5%.