It is often necessary to mark a capacitor with a marking or code that indicates the temperature coefficient of the capacitor. These capacitor codes are standardised by EIA, but also some other generally used industry codes may also be seen in common use. These codes are typically used for ceramic and other film type capacitors.
This capacitor marking code uses three characters. It bears many similarities to the numeric code system adopted for some surface mount resistors. The first two figures refer to the significant figures of the capacitor value, and the third one acts as a multiplier.
Colour code: Some older capacitors use a form of colour code. This type of capacitor marking is used less these days but may be seen on some older capacitors. Tolerance codes: Some capacitors have a tolerance code. The code used is actually the same as that used with resistors as it utilises the EIA scheme:
Thus, for such concise markings many different types of schemes or solutions are adopted. The value of the capacitor is indicated in “Picofarads”. Some of the marking figures which can be observed are 10n which denotes that the capacitor is of 10nF. In a similar way, 0.51nF is indicated by the marking n51.
• Ceramic Capacitor Markings Ceramic capacitors, known for their small size, use concise markings with digits and letters to indicate capacitance values. These codes convey information in minimal space, often including a base capacitance value followed by a letter for tolerance or temperature coefficient.
The capacitors which are small in size does not provide space required for clear markings and only few figures can be accommodated in the given space in order to mark it and provide a code for their various parameters. Thus, abbreviated markings are used in such cases wherein three characters are used to mark the code of the capacitor.