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Electronics Crib Sheet - Resistor Colour and Number Codes
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Resistor Colour Codes
 Note If there is only 3 colour bands, the missing one will be band d. The absence of band d implies the resistor accuracy is ±20% To read the code, 1. Write down the digit provided by the colour of band a 2. Write down the digit provided by the colour of band b 3. Write down the multiplier provided by the colour of band c 4. You have found the resistance in Ohms 5. If band d is present, this indicates the accuracy of the component. | |||
| a | b | c | d |
 0 |
0 |
x100Ω |
|
 1 |
1 |
x101Ω |
±1% |
 2 |
2 |
x102Ω |
±2% |
 3 |
3 |
x103Ω |
|
 4 |
4 |
x104Ω |
 ±5% |
 5 |
5 |
x105Ω |
|
 6 |
6 |
x106Ω |
|
 7 |
7 |
x107Ω |
|
 8 |
8 |
x108Ω |
 ±10% |
 9 |
9 |
x109Ω |
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Three Digit Resistor Number Codes
 1. Write down the first 2 digits (shown as a on the diagram) 2. Write down "x10" 3. Write down the x10 multiplier given by the third digit 4. This is the resistance in Ohms Here are some examples 234 = 23 x104Ω = 230kΩ 170 = 17 x100Ω = 17Ω 135 = 13 x105Ω = 1.3MΩ |
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Number and One Letter Resistor Codes
 1. Write down all digits before the letter. (If there are no digits before the letter then write "0") 2. Write down a decimal point "." 3. Write down all the digits after the letter 4. Look the letter up in this table and write down the answer
Here are some examples 23M45 = 23 . 45 M Ω = 23.45MΩ 470k = 470 . 0 k Ω = 470kΩ 1R2 = 1Ω2 = 1.2Ω 1k = 1kΩ 12G0 = 12.0GΩ G47 = 0.47GΩ = 470MΩ |
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