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Resistor Colour Code
Computer Laboratory > Course material 2006-07 > 1A Hardware Workshops > Resistor Colour Code

Appendix C

Resistor Colour Code

Resistors are normally coded with coloured bands to enable quick identification of their value. The colour code specifies the value of the resistor, in ohms, and the maximum deviation from the stated value (the tolerance). Most resistors have a manufacturer's tolerance with is adequate for most electronic applications

Interpreting the Colour Code

The four colour code bands are at one end of the component. Counting from the end, the first three (or sometimes four) bands give the resistance value and the last the tolerance. The significance of the colours is shown in the table below:

First 3 (or 4) bandsTolerance band
Yellow4No band20%

Reading the value (three band)

The first two bands are used to specify the first two digits of the resistor's value. The third gives the number of noughts to be added. Thus in this example, yellow and violet give the first two digits as 4 and 7 and the number of zeros is 3 (orange) giving a value of 47000 ohms.

Four Band Resistors

More modern resistors use four bands to specify the resistance, the first three giving the three most significant digits and the fourth the number of zeros. Yellow, violet, black, red decodes as 4, 7, 0, 00 ie. 47000 ohms.