General

Resistor values are often identified by a color code scheme.  On most resistors of 5% tolerance or greater, there are usually four bands, with the first three aligned towards one end of the resistor and the fourth on the opposite end.  The first two bands denote the first and second significant digits of the resistor value, the third band represents a multiplier, and the fourth band represents the resistor tolerance.

On resistors of tighter tolerance, usually 3% and lower, there will be a third significant digit, for a total of five bands, again with the first four aligned towards one end of the resistor and the fifth on the opposite end.   Occasionally you will see the value printed on resistors in the 4-digit numerical code format, with a letter indicating tolerance.

The table shown below lists the colors and letters used to identify the resistor values and tolerances.

 

Examples

• Four band code:

Brown, black, red, with a gold tolerance band:   10 x 100 = 1000 ohms (or 1K ohms), with a tolerance of 5%

Orange, orange, orange, with a silver tolerance band:  33*1000 = 33,000 ohms (33K ohms), with a tolerance of 10%

Yellow, violet, brown, with no tolerance band: 47*10 = 470 ohms, with a tolerance of 20%

Yellow, violet, yellow, with a gold tolerance band: 47*10,000 = 470,000 ohms (470K ohms), with a tolerance of 5%

• Five band code:

Blue, white, grey, red, with a red tolerance band:  698*100 = 69,800 ohms (69.8K ohms), with a tolerance of 2%

Green, brown, brown, black, with a brown tolerance band: 511*1 = 511 ohms, with a tolerance of 1%

Brown, black, black, brown, with a brown tolerance band:  100*10 = 1000 ohms (1.00K), with a tolerance of 1%

Brown, green, black, gold, with a brown tolerance band: 150 * 0.1 = 15.0 ohms, with a tolerance of 1%
 

• 4-digit numerical code:

2741F = 274*10 = 2740 ohms (2.74K) with a tolerance of 1%

3320F = 332*1 = 332 ohms, with a tolerance of 1%

1001G = 100*10 = 1000 ohms (1.00K) with a tolerance of 2%