The standard CEI 60063 , entitled Series of normal values for resistances and condensing , defines the values preferentially used for the Electronics components of the condensing type resistance and .

It defines several series, named Enn, where N are the number of values in a Décade (i.e. between 10^d included and 10^d+1 excluded, d  being a whole unspecified).

The values of the tables below are given for only one decade, the others are obtained while multiplying by 10^d, with D whole unspecified. For example one has in the E3 series of resistances of 4,7Ω, 47Ω, 470Ω, 4,7kΩ, 47kΩ, etc

Series with two digits

These series are in theory associated with a tolerance (E3: ±20%, E6: ±10%, E12: ±5%, E24: ±2%), but one finds in the various manufacturers of many exceptions to this rule.

These values were selected so that they are spaced regularly on a scale logarithmique.
(As for the notes of musics spaced regularly on a logarithmic scale, in 12 notes per octave).
Here an example. By taking the twelfth root of 10 like increment. Correspondent with E12.
$\backslash \; sqrt\; \{10\}\; =\; 1,2115\dots$

It is noticed that one finds almost the values of resistances of table précédent.

Series with three digits

These series are used in practice almost only for the precision resistors ±1% or better.

See too

Internal bonds

• CEI 60757 Code of the colors of location of resistances

External bonds

• Official site of the CEI

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