Capacitor Colour Codes

Capacitor Colour Codes

Generally, the values of Capacitance, Voltage or Tolerance are marked onto the body of the capacitors. However, when the value of the capacitance is of a decimal value problems arise with the marking of a "Decimal Point" as it could easily no be noticed resulting in a misreading of the actual value. Instead letters such as p (pico) or n (nano) are used in place of the decimal point to identify its position. For example, a capacitor can be labelled as, n47 = 0.47nF, 4n7 = 4.7nF or 47n = 47nF.

To reduce the confusion regarding letter, numbers and decimal points, an International colour coding scheme was developed many years ago as a simple way of identifying capacitor values and tolerances. It consists of coloured bands (in spectral order) whose meanings are illustrated below:

Capacitor Colour Code Table

Like resistors, small capacitors such as film or disk types conform to the BS1852 Standard where the colours are replaced by a letter or number coded system. The code consists of 2 or 3 numbers and an optional tolerance letter code. Where a two number code is used the value of the capacitor only is given in picofarads (ie. 47 = 47 pF). A three letter code consists of the two value digits and a multiplier much like a resistor colour code (ie. 471 = 47*10 = 470pF). Three digit codes are often accompanied by an additional tolerance letter code as given below.

Capacitor Tolerance Letter Codes Table

Consider the capacitor below:

The capacitor on the left is of a ceramic disc type capacitor that has the code 473J printed onto its body. This translates to:    47pF * 1,000 (3 zero's) = 47,000 pF , 47nF or 0.047 uF  the J indicates a tolerance of +/- 5%

Then just by using number and Letter codes on the body of the capacitor we can easily determine the value of its capacitance either in Picofarad's, NanoFarads or Microfarads and these codes are given in the following table along with the equivalent capacitances.

Capacitor Letter Codes Table