TheE series is a system ofpreferred numbers (also called preferred values) derived for use inelectronic components. It consists of theE3,E6,E12,E24,E48,E96 andE192 series,^[1] where the number after the 'E' designates the quantity oflogarithmic value "steps" perdecade. 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 forresistors,capacitors,inductors, andzener diodes. Other types of electrical components are either specified by theRenard series (for examplefuses) or are defined in relevant product standards (for exampleIEC 60228 for wires).

During theGolden Age of Radio (1920s to 1950s), numerous companies manufacturedvacuum-tube–basedAM radioreceivers for consumer use. In the early years, many components were not standardized between AM radio manufacturers. The capacitance values of capacitors (previously called condensers)^[2][3] and resistance values of resistors^[4][5][6][7] were not standardized as they are today.^[8]

In 1924, theRadio Manufacturers Association (RMA) was formed inChicago, Illinois by 50 AM radio manufacturers to license and share patents. Over time, this group created some of the earliest standards for electronics components. In 1936, the RMA adopted a preferred-number system for the resistance values of fixed-composition resistors.^[9] Over time, resistor manufacturers migrated from older values to the 1936 resistance value standard.^[6][7]

DuringWorld War II (1940s), American and Britishmilitary production was a major influence for establishingnumerous standards across many industries, especially in electronics, where it was essential to produce high quantities of standardized electronic components to build military devices, such aswireless communications and jammers,radar andjammers,LORAN radio navigation homing receivers for aircraft, ASDIC (sonar) for submarine navigation and detection, test equipment, andmore.

Later, themid-20th century baby boom and the invention of thetransistor kicked off demand forconsumer electronics goods during the 1950s. As portabletransistor radio manufacturing migrated from United States towards Japan during the late 1950s, it was critical for the electronic industry to have international standards.

After worked on by theRMA,^[10] theInternational Electrotechnical Commission (IEC) began work on an international standard for preferred values in 1948.^[11] The first version of thisIEC Publication 63 (IEC 63) was released in 1952.^[12] Later, IEC 63 was revised, amended, and renamed into the current version known asIEC 60063:2015.^[13]

IEC 60063 release history:

• IEC 63:1952 (aka IEC 60063:1952), first edition, published 1952-01-01.^[12]
• IEC 63:1963 (aka IEC 60063:1963), second edition, published 1963-01-01.^[11]
• IEC 63:1967/AMD1:1967 (aka IEC 60063:1967/AMD1:1967), first amendment of second edition, published 1967.^[11]
• IEC 63:1977/AMD2:1977 (aka IEC 60063:1977/AMD2:1977), second amendment of second edition, published 1977.^[11]
• IEC 60063:2015, third edition, published 2015-03-27.^[13]

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 alogarithmic scale. Each E series subdivides eachdecade magnitude into steps of 3, 6, 12, 24, 48, 96, and 192 values, termedE3,E6, and so forth toE192, with maximum errors of 40%, 20%, 10%, 5%, 2%, 1%, 0.5%, respectively.^{[nb 1]} Also, the E192 series is used for 0.25% and 0.1% tolerance resistors.

Historically, the E series is split into two major groupings:

• E3, E6, E12, E24 aresubsets of E24. Values in this group are rounded to 2significant figures.
• E48, E96, E192 aresubsets of E192. Values in this group are rounded to 3 significant figures.

The formula for each value is determined by them-th root, but unfortunately the calculated values don't match the official values of all E series.^[14]

$${\displaystyle V_n=\mathrm{r}\mathrm{o}\mathrm{u}\mathrm{n}\mathrm{d}(\sqrt[m]{{10}^n})}$$

where:

${\displaystyle V_n}$ isrounded to 2significant figures (E3, E6, E12, E24) or 3 significant figures (E48, E96, E192),

${\displaystyle m}$ is aninteger of the E series group size (3, 6, 12, 24, 48, 96, 192),

${\displaystyle n}$ is an integer of${\displaystyle \{0,1,...,m-1\}.}$

exceptions:

The official values for E48 and E96 series match their calculated values, but all other series (E3, E6, E12, E24, E192) have one or more official values that don't match their calculated values (see subsets sections below).

For E3, E6, E12, and E24, the values from the formula are rounded to 2 significant figures, but eight official values (shown inbold & green) are different from the calculated values (shown in red). During the early half of the 20th century, electronic components had different sets of component values than today. In the late 1940s, standards organizations started working towards codifying a standard set of official component values, and they decided that it wasn't practical to change some of the former established historical values. The first standard was accepted in Paris in 1950, then published as IEC 63 in 1952.^[12] The official values of the E3, E6, and E12 series aresubsets of the following official E24 values.

Comparison of rounded log-scaled values and official values of E24 series (${\displaystyle m=24}$)

${\displaystyle n=\{0,...,23\}}$	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23
Calculated${\displaystyle V_n}$ values	1.0	1.1	1.2	1.3	1.5	1.6	1.8	2.0	2.2	2.4	2.6	2.9	3.2	3.5	3.8	4.2	4.6	5.1	5.6	6.2	6.8	7.5	8.3	9.1
Official E24 values	1.0	1.1	1.2	1.3	1.5	1.6	1.8	2.0	2.2	2.4	2.7	3.0	3.3	3.6	3.9	4.3	4.7	5.1	5.6	6.2	6.8	7.5	8.2	9.1

The E3 series is rarely used,^{[nb 1]} except for some components with high variations likeelectrolytic capacitors, where the giventolerance is often unbalanced between negative and positive such as^+50%
_−30% or^+80%
_−20%, or for components with uncritical values such aspull-up resistors. The calculated constant tangential tolerance for this series gives (³√10 − 1) ÷ (³√10 + 1) = 36.60%, approximately. While the standard only specifies a tolerance greater than 20%, other sources indicate 40% or 50%. Currently, most electrolytic capacitors are manufactured with values in the E6 or E12 series, thus E3 series is mostly obsolete.

For E48, E96, and E192, the values from the formula are rounded to 3 significant figures, but one value (shown in bold) is different from the calculated values.

• To calculate the E48 series:${\displaystyle m}$ is 48, then${\displaystyle n}$ is incremented from 0 to 47 through the formula. All official values of E48 series match their calculated values.
• To calculate the E96 series:${\displaystyle m}$ is 96, then${\displaystyle n}$ is incremented from 0 to 95 through the formula. All official values of E96 series match their calculated values.
• To calculate the E192 series:${\displaystyle m}$ is 192, then${\displaystyle n}$ is incremented from 0 to 191 through the formula, with one exception for${\displaystyle n=185}$ where9.20 is the official value instead of the calculated 9.19 value.

Since some values of the E24 series do not exist in the E48, E96, or E192 series, some resistor manufacturers have added missing E24 values intosome of their 1%, 0.5%, 0.25%, 0.1% tolerance resistor families. This allows easier purchasing migration between various tolerances. This E series merging is noted on resistor datasheets and webpages as "E96 + E24" or "E192 + E24".^[15][16][17] In the following table, the red cells denote E24 values that don't exist in the E48, E96, or E192 series, and indicate the closest value or values that do instead.

E24 values that exist in E48, E96, and E192 series

E24 values	1.0	1.1	1.2	1.3	1.5	1.6	1.8	2.0	2.2	2.4	2.7	3.0	3.3	3.6	3.9	4.3	4.7	5.1	5.6	6.2	6.8	7.5	8.2	9.1
E48 values	1.00	1.10	1.21	1.27 1.33	1.47	1.62	1.78	1.96	2.15	2.37	2.74	3.01	3.32	3.65	3.83	4.22	4.64	5.11	5.62	6.19	6.81	7.50	8.25	9.09
E96 values	1.00	1.10	1.21	1.30	1.50	1.58 1.62	1.78 1.82	2.00	2.21	2.37 2.43	2.67	3.01	3.32	3.57	3.92	4.32	4.75	5.11	5.62	6.19	6.81	7.50	8.25	9.09
E192 values	1.00	1.10	1.20	1.30	1.50	1.60	1.80	2.00	2.21	2.40	2.71	3.01	3.28 3.32	3.61	3.88 3.92	4.32	4.70	5.11	5.62	6.19	6.81	7.50	8.16	9.09

If a manufacturer sold resistors with all values in a range of 1ohm to 10 megaohms, the available resistance values for E3 through E12 would be:

E3 (in ohms)	E6 (in ohms)	E12 (in ohms)
1.0, 2.2, 4.7, 10, 22, 47, 100, 220, 470, 1 k, 2.2 k, 4.7 k, 10 k, 22 k, 47 k, 100 k, 220 k, 470 k, 1 M, 2.2 M, 4.7 M, 10 M	1.0, 1.5, 2.2, 3.3, 4.7, 6.8, 10, 15, 22, 33, 47, 68, 100, 150, 220, 330, 470, 680, 1 k, 1.5 k, 2.2 k, 3.3 k, 4.7 k, 6.8 k, 10 k, 15 k, 22 k, 33 k, 47 k, 68 k, 100 k, 150 k, 220 k, 330 k, 470 k, 680 k, 1 M, 1.5 M, 2.2 M, 3.3 M, 4.7 M, 6.8 M, 10 M	1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, 8.2, 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82, 100, 120, 150, 180, 220, 270, 330, 390, 470, 560, 680, 820, 1 k, 1.2 k, 1.5 k, 1.8 k, 2.2 k, 2.7 k, 3.3 k, 3.9 k, 4.7 k, 5.6 k, 6.8 k, 8.2 k, 10 k, 12 k, 15 k, 18 k, 22 k, 27 k, 33 k, 39 k, 47 k, 56 k, 68 k, 82 k, 100 k, 120 k, 150 k, 180 k, 220 k, 270 k, 330 k, 390 k, 470 k, 560 k, 680 k, 820 k, 1 M, 1.2 M, 1.5 M, 1.8 M, 2.2 M, 2.7 M, 3.3 M, 3.9 M, 4.7 M, 5.6 M, 6.8 M, 8.2 M, 10 M

If a manufacturer sold capacitors with all values in a range of 1pF to 10,000 μF, the available capacitance values for E3 and E6 would be:

E3

E6

1.0 pF, 2.2 pF, 4.7 pF, 10 pF, 22 pF, 47 pF, 100 pF, 220 pF, 470 pF, 1 nF, 2.2 nF, 4.7 nF, 10 nF, 22 nF, 47 nF, 100 nF, 220 nF, 470 nF, 1 μF, 2.2 μF, 4.7 μF, 10 μF, 22 μF, 47 μF, 100 μF, 220 μF, 470 μF, 1000 μF, 2200 μF, 4700 μF, 10000 μF

1.0 pF, 1.5 pF, 2.2 pF, 3.3 pF, 4.7 pF, 6.8 pF, 10 pF, 15 pF, 22 pF, 33 pF, 47 pF, 68 pF, 100 pF, 150 pF, 220 pF, 330 pF, 470 pF, 680 pF, 1 nF, 1.5 nF, 2.2 nF, 3.3 nF, 4.7 nF, 6.8 nF, 10 nF, 15 nF, 22 nF, 33 nF, 47 nF, 68 nF, 100 nF, 150 nF, 220 nF, 330 nF, 470 nF, 680 nF, 1 μF, 1.5 μF, 2.2 μF, 3.3 μF, 4.7 μF, 6.8 μF, 10 μF, 15 μF, 22 μF, 33 μF, 47 μF, 68 μF, 100 μF, 150 μF, 220 μF, 330 μF, 470 μF, 680 μF, 1000 μF, 1500 μF, 2200 μF, 3300 μF, 4700 μF, 6800 μF, 10000 μF

List of official values for each E series:^{[nb 1]}

E3 values

(40% tolerance)

1.0, 2.2, 4.7

E6 values

(20% tolerance)

1.0, 1.5, 2.2, 3.3, 4.7, 6.8

E12 values

(10% tolerance)

1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, 8.2

E24 values

(5% tolerance)

1.0, 1.1, 1.2, 1.3, 1.5, 1.6, 1.8, 2.0, 2.2, 2.4, 2.7, 3.0, 3.3, 3.6, 3.9, 4.3, 4.7, 5.1, 5.6, 6.2, 6.8, 7.5, 8.2, 9.1

E48 values

(2% tolerance)

1.00, 1.05, 1.10, 1.15, 1.21, 1.27, 1.33, 1.40, 1.47, 1.54, 1.62, 1.69, 1.78, 1.87, 1.96, 2.05, 2.15, 2.26, 2.37, 2.49, 2.61, 2.74, 2.87, 3.01, 3.16, 3.32, 3.48, 3.65, 3.83, 4.02, 4.22, 4.42, 4.64, 4.87, 5.11, 5.36, 5.62, 5.90, 6.19, 6.49, 6.81, 7.15, 7.50, 7.87, 8.25, 8.66, 9.09, 9.53

E96 values

(1% tolerance)

1.00, 1.02, 1.05, 1.07, 1.10, 1.13, 1.15, 1.18, 1.21, 1.24, 1.27, 1.30, 1.33, 1.37, 1.40, 1.43, 1.47, 1.50, 1.54, 1.58, 1.62, 1.65, 1.69, 1.74, 1.78, 1.82, 1.87, 1.91, 1.96, 2.00, 2.05, 2.10, 2.15, 2.21, 2.26, 2.32, 2.37, 2.43, 2.49, 2.55, 2.61, 2.67, 2.74, 2.80, 2.87, 2.94, 3.01, 3.09, 3.16, 3.24, 3.32, 3.40, 3.48, 3.57, 3.65, 3.74, 3.83, 3.92, 4.02, 4.12, 4.22, 4.32, 4.42, 4.53, 4.64, 4.75, 4.87, 4.99, 5.11, 5.23, 5.36, 5.49, 5.62, 5.76, 5.90, 6.04, 6.19, 6.34, 6.49, 6.65, 6.81, 6.98, 7.15, 7.32, 7.50, 7.68, 7.87, 8.06, 8.25, 8.45, 8.66, 8.87, 9.09, 9.31, 9.53, 9.76

E192 values

(0.5% and lower tolerance)

1.00, 1.01, 1.02, 1.04, 1.05, 1.06, 1.07, 1.09, 1.10, 1.11, 1.13, 1.14, 1.15, 1.17, 1.18, 1.20, 1.21, 1.23, 1.24, 1.26, 1.27, 1.29, 1.30, 1.32, 1.33, 1.35, 1.37, 1.38, 1.40, 1.42, 1.43, 1.45, 1.47, 1.49, 1.50, 1.52, 1.54, 1.56, 1.58, 1.60, 1.62, 1.64, 1.65, 1.67, 1.69, 1.72, 1.74, 1.76, 1.78, 1.80, 1.82, 1.84, 1.87, 1.89, 1.91, 1.93, 1.96, 1.98, 2.00, 2.03, 2.05, 2.08, 2.10, 2.13, 2.15, 2.18, 2.21, 2.23, 2.26, 2.29, 2.32, 2.34, 2.37, 2.40, 2.43, 2.46, 2.49, 2.52, 2.55, 2.58, 2.61, 2.64, 2.67, 2.71, 2.74, 2.77, 2.80, 2.84, 2.87, 2.91, 2.94, 2.98, 3.01, 3.05, 3.09, 3.12, 3.16, 3.20, 3.24, 3.28, 3.32, 3.36, 3.40, 3.44, 3.48, 3.52, 3.57, 3.61, 3.65, 3.70, 3.74, 3.79, 3.83, 3.88, 3.92, 3.97, 4.02, 4.07, 4.12, 4.17, 4.22, 4.27, 4.32, 4.37, 4.42, 4.48, 4.53, 4.59, 4.64, 4.70, 4.75, 4.81, 4.87, 4.93, 4.99, 5.05, 5.11, 5.17, 5.23, 5.30, 5.36, 5.42, 5.49, 5.56, 5.62, 5.69, 5.76, 5.83, 5.90, 5.97, 6.04, 6.12, 6.19, 6.26, 6.34, 6.42, 6.49, 6.57, 6.65, 6.73, 6.81, 6.90, 6.98, 7.06, 7.15, 7.23, 7.32, 7.41, 7.50, 7.59, 7.68, 7.77, 7.87, 7.96, 8.06, 8.16, 8.25, 8.35, 8.45, 8.56, 8.66, 8.76, 8.87, 8.98, 9.09, 9.20, 9.31, 9.42, 9.53, 9.65, 9.76, 9.88

• Electronic color code – color-code used to indicate the values of axial electronic components, such as resistors, capacitors, inductors, diodes (also seeIEC 60062)
• Geometric progression
• Preferred number
• Renard series – used for current rating of electric fuses
• Three-character marking code for resistors – for (E48/)E96 values (see EIA-96 and IEC 60062:2016)
• Two-character marking code for capacitors – for (E3/E6/E12/)E24 values (see ANSI/EIA-198-D:1991, ANSI/EIA-198-1-E:1998, ANSI/EIA-198-1-F:2002 and IEC 60062:2016/AMD1:2019)
• Reference designator – Location identifier for a circuit component

Wikimedia Commons has media related toE12 values.

• Calculate the closest component value to any E-series with anExcel User Defined Function.
• Calculate standard resistor values in Excel – EDN magazine
• OEISsequence A072198 (E12)
• OEISsequence A072554 (E24)

Printable E series tables

• E6 to E96 Table – Servenger
• E3 to E192 Table – Vishay

• Electrical components
• Numbers
• Industrial design
• Logarithmic scales of measurement

• Articles with short description
• Short description is different from Wikidata
• Use dmy dates from August 2021
• Use list-defined references from December 2021
• Commons category link is locally defined