The capacitor on the left is of a ceramic disc type capacitor that has the code 473J printed onto its body. Three digit codes are often accompanied by an additional tolerance letter code as given below. A three letter code consists of the two value digits and a multiplier much like the resistor colour codes in the resistors section.įor example, the digits 471 = 47*10 = 470pF. Where a two number code is used the value of the capacitor only is given in picofarads, for example, 47 = 47 pF and 100 = 100pF etc. Generally the code consists of 2 or 3 numbers and an optional tolerance letter code to identify the tolerance. Nowadays, small capacitors such as film or disk types conform to the BS1852 Standard and its new replacement, BS EN 60062, were the colours have been replaced by a letter or number coded system. This system of colour coding is now obsolete but there are still many “old” capacitors around. The Capacitor Colour Code system was used for many years on unpolarised polyester and mica moulded capacitors.
To reduce the confusion regarding letters, numbers and decimal points, an International colour coding scheme was developed many years ago as a simple way of identifying capacitor values and tolerances. Also, sometimes capacitors are marked with the capital letter K to signify a value of one thousand pico-Farads, so for example, a capacitor with the markings of 100K would be 100 x 1000pF or 100nF. Instead letters such as p (pico) or n (nano) are used in place of the decimal point to identify its position and the weight of the number.įor example, a capacitor can be labelled as, n47 = 0.47nF, 4n7 = 4.7nF or 47n = 47nF and so on. However, when the value of the capacitance is of a decimal value problems arise with the marking of the “Decimal Point” as it could easily not be noticed resulting in a misreading of the actual capacitance value.