The capacitor symbol consistently represents capacitors in electrical schematics and circuit designs. This symbol provides essential information about the circuit's capacitor's type, value, and polarity. Engineers and technicians can understand the capacitor's function and characteristics without physically inspecting the component.
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.
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.
The different types of coding system used for the capacitors are: Colour Code: A “colour code” is used in capacitors which are old. In the present times, industry rarely use colour code system except seldom on some of the components. Tolerance Codes: The tolerance code is used in some of the capacitors.
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. The temperature coefficient is quoted in terms of parts per million per degree C; PPM/°C.
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: