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Resistor colour codes

resistor colour code example

Resistors are normally labelled using 4 coloured bands across the body of the resistor. This consists three bands together indicating the resistance value of the resistor (ohms) and the forth, further away than the first three, is used to indicate the tolerance (accuracy) of the resistor. Some resistors have a 5th band indicating the failure rate of the resistor required for military use.

The bands relate to the resistance as follows:

  • 1st band - first significant figure of resistor value
  • 2nd band - second significant figure of resistor value
  • 3rd band - decimal multiplier (applied against first two bands)
  • 4th band - tolerence (if not present tolerence is 20%)
ColourSignificant figuresMultiplierTolerance
Black0x100 -
Brown1x101 ±1%
Red2x102 ±2%
Orange3x103 -
Yellow4x104 -
Green5x105 ±0.5%
Blue6x106 ±0.25%
Violet7x107 ±0.1%
Grey8x108 ±0.05%
White9x109 -
Gold - x10-1 ±5%
Silver - x10-2 ±10%
None - - ±20%

The example above has colours: Red, Green, Blue ... Silver.
This translates to 2 (red), 5 (green), x106 (blue), with a tolerence of 10%.
which is 25,000,000Ω or 25MΩ.
The tolerence is not normally a major consideration for most circuits, but if the exact value of the resistor is required then that band should be considered as well.

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