E series of preferred numbers

It consists of the E3, E6, E12, E24, E48, E96 and E192 series,[1] where the number after the 'E' designates the quantity of logarithmic value "steps" per decade.

Although it is theoretically possible to produce components of any value, in practice the need for inventory simplification has led the industry to settle on the E series for resistors, capacitors, inductors, and zener diodes.

Other types of electrical components are either specified by the Renard series (for example fuses) or are defined in relevant product standards (for example IEC 60228 for wires).

In 1936, the RMA adopted a preferred-number system for the resistance values of fixed-composition resistors.

[6][7] During World War II (1940s), American and British military production was a major influence for establishing common standards across many industries, especially in electronics, where it was essential to produce large quantities of standardized electronic parts for military devices, such as wireless communications, radar, radar jammers, LORAN, and more.

Later, the mid-20th century baby boom and the invention of the transistor kicked off demand for consumer electronics goods during the 1950s.

As portable transistor radio manufacturing migrated from United States towards Japan during the late 1950s, it was critical for the electronic industry to have international standards.

[13] IEC 60063 release history: The E series of preferred numbers was chosen such that when a component is manufactured it will end up in a range of roughly equally spaced values (geometric progression) on a logarithmic scale.

Each E series subdivides each decade magnitude into steps of 3, 6, 12, 24, 48, 96, and 192 values, termed E3, E6, and so forth to E192, with maximum errors of 40%, 20%, 10%, 5%, 2%, 1%, 0.5%, respectively.