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.
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
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
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