Electronic color code

Electronic color codes are used on electronic components, such as resistors and capacitors, to indicate values or ratings. They have also been used on signaling wire and cable as well, particularly for telephone and digital bus cables. The color-digit pairs used in the resistor example below are standard, but the tolerance and higher multiplier values are for resistors only.

Resistor Example

      +- - - - - - - - - - - - -+
      |AA  BB  CC  DD           |
   ---|AA  BB  CC  DD           |---
      |AA  BB  CC  DD           |
      +- - - - - - - - - - - - -+

band A is first significant figure of resistance value in ohms
band B is the second significant figure
band C is the decimal multiplier
band D if present, indicates tolerance of value in percent (no color means 20%)

  color     sig fig    decimal    tolerance
  of band   or # 0s   multiplier    +/-

   black       0         10^0
   brown       1         10^1        1%
   red         2         10^2        2%
   orange      3         10^3        3%
   yellow      4         10^4        4%
   green       5         10^5
   blue        6         10^6
   violet      7         10^7
   gray        8         10^8
   white       9         10^9
   gold                   0.1        5% (or letter "J")
   silver                 0.01      10% (or letter "K")
   no color                         20% (or letter "M")

Resistors are measured in ohms, so yellow violet red brown means 4700 ohms, 1% tolerance.

Capacitors are measured in pF, so yellow violet red means 4.7nF.

An alternative method of marking components is to write the digits and power of ten involved. Eg a resistor marked 472 is 4700 ohms; a capacitor marked 104 is 100nF (100000pF).