Identifying Resistors

In electronic circuits there are many resistors. Most are physically small and are identified by coloured bands. Newer boards contain very small devices that are surface mounted and have their value printed on them. These are not easy to distinguish from small capacitors. Reistors which have a higher power rating may have their resistance value printed on them.

The Resistor Color Code

The colour coding my have 4 or 5 bands. One system is shown below (band 5 may not be present). A slightly different coding has a third band that works in a similar way to bands 1 and 2. Band 4 then becomes the multiplier and the remaining band the tolerance.

  Colour Band 1 Band 2 Band 3 Band 4 Band 5
  Black00x1  200 ppm
  Brown11x101%100 ppm
  Red22x1002%50 ppm
  Orange33x1000  15 ppm
  Yellow44x10,000  25 ppm
  Blue66x1,000,0000.25%10 ppm
  Grey77  0.1%5 ppm
  White88    1 ppm
  Gold99  5% 
  Silver      10%