A capacitor marking is a code, which indicates the value of the component. It usually consists of three numbers, which indicates the value, and a letter, which indicates the tolerance. Tables usually provide a means to decode the numbers; however, there are also calculators available as well.
• 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.
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.
Similarly n51 indicates a 0.51nF, or 510 pF capacitor, etc . . SMD ceramic capacitor codes: Surface mount capacitors are often very small and do not have the space for markings. During manufacture the capacitors are loaded into a pick and place machine and there is no need for any markings.
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.
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: