Capacitors are often marked with codes to show the value, tolerance and material. This is particularly true for small types such as ceramic disc or polystyrene where there is little space for full markings.
The capacitance value is often marked using a 3 digit code. This works in the same way as resistor coding but using numbers instead of colours. The first 2 numbers give the value and the last number is the multiplier. These give the value in Picofarads (pF), e.g. code 103 = 1 0 000pF (=0.01uF - see Capacitance Conversion Table). Alternatively the value may be marked directly, for example 2n2 is 2.2 Nanofarads (nF).
A single letter is often used to indicate the tolerance of the component. These can be translated using the following table:
Tolerance Code | Tolerance |
---|---|
C | +/- 0.25pF |
D | +/- 0.5pF |
F | +/- 1% |
G | +/- 2% |
J | +/- 5% |
K | +/- 10% |
M | +/- 20% |
Z | - 20% +80% |
The dielectric material is often marked in abbreviated form. The table below shows the meaning of these abbreviations.
Marking | Material |
---|---|
MKT | Metallised Polyester (PETP) |
MKC | Metallised Polycarbonate |
KT | Polyester Film / Foil |
KS | Polystyrene Film / Foil |
KP | Polypropylene Film / Foil |
MKP | Metallised Polypropylene |