Capacitor Value Conversions


CAPACITOR CODES

VOLTAGE RATING

TOLERANCE


CAPACITOR CODES

Most capacitors will have their value printed on them.
However there are a number of capacitors manufacturers who use the 'IEC' code. the 'IEC' code is a numerical code that works in a similar way to the resistor colour code: two figures followed by a multiplier.

Quite often there is a single letter, indicating tolerance.

The code is worked out in picofarads, so there is a chance you may have to use the appropriate multiplier. For example a capacitor may have a code '104k'. This decodes as OluF 10%. The first two figures give 10 the third figure'4' gives 0000 and the last 'k' = 10%. Therefore, the capacitor is 10,0000pF, 10%. This is normally expressed as 0.0luF or l00nF - capacitors with a value below 0.001uF are expressed in Picofarads.

There may be a further figure marked on the capacitor, this would normally be the maximum voltage rating.

1st figure of value
2nd figure of value
Number of Zeros (multiplier)
Tolerance (+/-%)

    pF

    nF

    uF

    mF

    EIA Code

    100

    0.1

    0.0001

    -

    l0l

    820

    0.82

    0.00082

    -

    821

    1000

    1

    0.001

    -

    102

    8200

    8.2

    0.0082

    -

    822

    10,000

    10

    0.01

    -

    103

    82,000

    82

    0.082

    -

    823

    100,000

    100

    0.1

    0.0001

    104

    -

    820

    0.82

    0.00082

    824

    -

    1,000

    1

    0.001

    105

    -

    8,200

    8.2

    0.0082

    825

    -

    10,000

    10

    0.01

    106

    -

    82,000

    82

    0.082

    826

    -

    100,000

    100

    0.1

    107

    -

    -

    820

    0.82

    827

    -

    -

    1000

    1

    108

    -

    -

    8200

    82

    828

    -

    -

    10,000

    10

    109

    -

    -

    82,000

    82

    829

    -

    -

    100,000

    100

    -

    -

    -

    -

    820

    -

    -

    -

    -

    1000

    -

VOLTAGE RATING

Usually capacitors are marked with the 'V' symbol.

Most electrolytics clearly indicate their voltage rating polyester or greencaps usually show the voltage - less the 'V' symbol. Quite often ceramics show no voltage ratings at all.

TOLERANCE

Tolerance indicates how close the capacitors marked value is to its actual value A tolerance can be marked several ways, numerically, as a code. Consisting of a single letter or a colour band or dot. Tolerance code letters are usually placed immediately after the value. Commonly used tolerance codes are:

Code Colour Tol. Code Colour Tol.
A - +20-10(z) L - +/-15%
C Red +/-0.25pf M Black +/-20%
D Green +/-0.5pf N - + /-30%
E White +/-1pf P - + 100 -0
F Brown +/-1% Q(2) - +30-10
G Red +/-2% S - +50-20
J Green +/-5% W - +50-10
White +/-IO% W(2) - +40-20
Z Grey +80-20