Resistor color codes

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The resistor color code is used to indicate the value of through hole resistors below 1 Watt. Surface mount resistor markings are generally an alphanumeric code. On large power resistors and potentiometers the value is usually given explicitly. The codes are defined in IEC 60062.

Preferred values[edit | edit source]

Resistors are available mainly in two series of preferred values, E12 (12 values per decade) and E24 (24 values per decade). Carbon resistors with a tolerance 5% and less are available in the E12 series while metal film resistors with 2% and better tolerance are available in the E24 series.

Help to remember[edit | edit source]

Without a mnemonic: Black is darkest, brown is a dark shade of red, then the color spectrum ROY G. BV, then grey as colour is lost, and white is brightest. Gold has a better value than silver.

How to read[edit | edit source]

The first band is closest to one end. If there is a gap between bands 3 and 4, band 4 is the tolerance. Gold or silver gives the tolerance and the tolerance is usually the last band. Pink for the tolerance band shows it's ±20%.

A resistor with a single black band is a zero-ohm resistor and can be replaced by a wire link.

Colour chart for 4, 5 and 6 bands resistors
Colour chart for 4, 5 and 6 bands resistors

Approximate power rating of through hole resistor sizes[edit | edit source]

There is no standard specification for power rating of particular through hole resistor sizes. Only the seller or data sheet for a specific resistor can confirm its power rating.

Key resistor dimensions
Key resistor dimensions

Carbon film[edit | edit source]

Watts Length (mm) Diameter (mm)
1/8 3.5 1.85
1/4 6.8 2.5
1/2 10.0 3.5
1W 16.0 5.5
2W 17.5 6.5

[1]

Metal film[edit | edit source]

Watts Length (mm) Diameter (mm)
1/8 3.5 1.85
1/4 6.8 2.5
1/2 10.0 3.5
1 12.0 5,0
2 16.0 5.5
3 17.5 6.5

[2]

See also[edit | edit source]

Notes[edit | edit source]

References[edit | edit source]

  1. ^ Carbon film fixed resistors, Royal Ohm, 18 Aug 2018
  2. ^ Precision metal film fixed resistors, Royal Ohm, 18 Aug 2018

Further reading[edit | edit source]

  • A Users Guide to Selecting Electronic Components by Gerald L Ginsberg, John Wiley & Sons Inc, 1981, ISBN 0-471-08308-9
  • Passive Components: a user's guide by Ian Robertson Sinclair, Butterworth-Heinemann Ltd, 1991, ISBN 0-7506-0229-5

External links[edit | edit source]