It works similarly to the Renard series, except that it subdivides the interval from 1 to 10 into 3, 6, 12 and 24, and later also 48, 96 or 192 steps. These subdivisions ensure that when some arbitrary value is replaced with the nearest preferred number, the maximum relative error will be on the order of 40%, 20%, 10%, 5%, etc.
Use of the IEC or EIA E series is mostly restricted to resistors, capacitors, inductors and Zener diodes. Commonly produced dimensions for other types of electrical components are either chosen from the Renard series instead (for example fuses) or are defined in relevant product standards (for example wires).
The IEC 60063 numbers are as follows. The E6 series is every other element of the E12 series, which is in turn every other element of the E24 series:
^The E3 series is rarely used, except for some components with high variations like electrolytic capacitors, where the given tolerance is often unbalanced such as −30/+50% or −20/+80%, or for components with uncritical values such as pull-up resistors. The calculated tolerance for this series gives (101/3 − 1) ÷ (101/3 + 1) = 36.60%. While the standard only specifies a tolerance greater than 20%, other sources indicate 40% or 50%.