How to Read Resistor Colour Codes

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This guide is relevent to all resistors, it is written to support the sales of all sizes of E12 resistors, 1/4 watt  from my shop mallinson-electrical.

100 to 820 ohm 1000 to 8200 ohm 10k to 82k 100k to 1M

Most Resistors used in electronics will be colour coded to give their value.

This is a brief explanation of how to read the codes on the most commonly used resistors, namely the values in the E12 series

it is a simple matter of reading from left to right and assigning a value to the coloured bands.

The final band (band 4) indicates the tolerance of the resistor

To determine which way round to read the resistor is easy enough, if you read the number correctly it will be one of the standard sizes available

The E12 series all start with one of these values;

10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68 or 82

there are, as you can see "12" values, hence E12. No matter which resistor you pick up it will be one of these values, multiplied by a factor of 10.

An example

code Brown, Black, Green, Gold

reading this way round gives 1,0, x100,000, 5% = 1,000,000 with 5% tolerance i.e. 1 Mohm

It cannot be the other way round, as no resistor starts with Gold

Another example

code Brown, Red, Brown, Red

read this way = 1,2,x10, 2%tolerance    =120 ohms    ok

read in reverse= 2, 1, x100, 1%           = 2100 ohms. There is no value in E12 starting 2,1, so it must be the first way we tried.

need resistors? try my eBay shop Mallinson-Electrical

All Resistor Listings have a colour code chart on the page


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