Resistors

Resistor 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	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

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

Letter	Answer
R	Ω
k	kΩ
M	MΩ
G	GΩ

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