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Electronics Crib Sheet - Resistor Colour and Number Codes
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 | x10^{0}Ω | |
1 | 1 | x10^{1}Ω | ±1% |
2 | 2 | x10^{2}Ω | ±2% |
3 | 3 | x10^{3}Ω | |
4 | 4 | x10^{4}Ω | ±5% |
5 | 5 | x10^{5}Ω | |
6 | 6 | x10^{6}Ω | |
7 | 7 | x10^{7}Ω | |
8 | 8 | x10^{8}Ω | ±10% |
9 | 9 | x10^{9}Ω |
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 x10^{4}Ω = 230kΩ 170 = 17 x10^{0}Ω = 17Ω 135 = 13 x10^{5}Ω = 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
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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