Resistors and their colour codes

 Resistors are passive elements in electronic circuits meaning that they do not need a power supply unlike active devices which need a power supply for them to function. Other common passive elements used in electronic circuits are capacitors and inductors. Resistance of a resistor is expressed in Ohms. Higher values may be expressed as Kilo Ohms or Mega Ohms. Kilo Ohms meaning 1000 Ohms and Mega Ohms meaning million ohms.


Resistors come in different wattages depending on their size, indicating heat dissipation capacity. The resistors shown here are quarter Watt resistors while half Watt and one Watt resistors are also available. Higher and smaller denominations are also used in specific applications depending on the circuit demand.

The value of the resistor is indicated on the resistor with a colour code. The resistors shown here have a four band colour code, which is the most common one in use. First two bands indicate the resistance value which has to be multiplied by the code on the third band. Fourth band indicates the tolerance. If there is no tolerance band, the tolerance is presumed to be 20%.

How to Read Resistor Colour Code?  Colour code values are as follows: Black 0, Brown 1, Red 2, Orange 3, Yellow 4, Green 5, Blue 6, Violet 7, Grey 8, White 9. Golden colour is for 5% tolerance while Silver colour is for 10% tolerance. As mentioned above if there is no tolerance band, it implies 20% tolerance. Third band is used as multiplier for the first two bands. Multiplication is by ten to the power of the third band colour code. Multiply by 1 if it is black, by 10 if it is brown, by 100 if it is red etc.

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