Resistor Page

Our Friend the Resistor

(How to Read a Resistor Color Code)

1 -- Digit 1 (the color band that's closest to an end)

2 -- Digit 2

3 -- Multiplier (what you multiply the first two digits by)

4 -- Precision of Resistor (not always present)

To determine the value of a resistor, multiply the value of Digits 1 & 2 by the Multiplier. (The precision of the resistor is not relevant for this calculation.)

For example

  • 10 = 10 x 1
  • 100 = 10 x 10
  • 1 K = 10 x 100
  • 1 M = 10 x 100,000

Color Codes

For each of the first two bands:

  • Black = 0
  • Brown = 1
  • Red = 2
  • Orange = 3
  • Yellow = 4
  • Green = 5
  • Blue = 6
  • Purple = 7
  • Gray = 8
  • White = 9

For the multiplier band:

  • Black = 1
  • Brown = 10
  • Red = 100
  • Orange = 1,000
  • Yellow = 10,000
  • Green = 100,000
  • Blue = 1,000,000
  • Gray = 1/100
  • Gold = 1/10

Examples

(1 & 2) x Multiplier:

  • 25 = Red-Green-Black
  • 250 = Red-Green-Brown
  • 2,500 (2.5K) = Red-Green-Red
  • 1,200,000 (1.2M) = Brown- Red-Green

Tim Cannon's Homepage

Department of Psychology

Neuroscience Program

University of Scranton