E-series of preferred numbers

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This graph shows how almost any value between 1 and 10 is within ±10% of an E12 series value, and its difference from the ideal value in a geometric sequence
Two decades of E12 values, which would give resistor values of 1 Ω to 82 Ω

The E-series is a system of preferred numbers (also called preferred values) derived for use in electronic components. It consists of the E1, E3, E6, E12, E24, E48, E96 and E192 series, where the number after the 'E' designates the quantity of value "steps" in each series. 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).

History[edit]

World War II military production was a major influence for establishing common standards across many industries. Later, Post–World War II baby boom and invention of the transistor kicked off demand for consumer electronics goods during the 1950s. As transistor radio production migrated towards Japan during the 1950s, it was critical for the electronic industry to have international standards.

In the early 20th century,[1][2][3][4] resistor and capacitor value increments were much different than today.[5] Over time, products evolved towards common values and eventually was documented to become an official standard, such as 1963 IEC Publication 63 (IEC 63),[6] created by the International Electrotechnical Commission (IEC). Later IEC 63 was renamed, amended, revised into the current version known as IEC 60063:2015.[7]

IEC 60063 release history:

  • 1952 – 1st edition.[8]
  • 1963 – 2nd edition.[6]
  • 1967 – Amendment 1.[6]
  • 1977 – Amendment 2.[6]
  • 2015 – 3rd edition.[7]

Overview[edit]

E-series preferred numbers were chosen such that when a component is manufactured that it will end up in a bin of roughly equally spaced values on a logarithmic scale. Each E-series subdivides the interval from 1 to 10 (decade) into steps of 1, 3, 6, 12, 24, 48, 96, 192. Subdivisions of E3 to E192 ensure the maximum error will be divided in the order of 40%, 20%, 10%, 5%, 2%, 1%, 0.5%. Also, the E192 series is used for 0.25% and 0.1% tolerance resistors.

Currently, the E-series is split into two major groupings: up to E24 is one group, and E48 and higher is the other group. The two main differences between each major group is the number of significant digits (2 digits for E3 to E24, 3 digits for E48 to E192) and different rounding rules. Since lower E-series up to E24 were defined and established long before the IEC standards were written, older series were not redefined when E48 to E192 series were created, otherwise it would have created problems in production and servicing of established products. It should be noted that some values in the E24 series don't exist in E48 to E192 series.

Example[edit]

The E3 series is defined as three numbers consisting of 1.00, 2.20, 4.70. If a manufacturer sold resistors with E3 series values in a range of 1 ohm to 10 megaohms, then the available resistance values (in ohm (Ω)) would be: 1, 2.2, 4.7, 10, 22, 47, 100, 220, 470, 1K, 2.2K, 4.7K, 10K, 22K, 47K, 100K, 220K, 470K, 1M, 2.2M, 4.7M, 10M.

Obsolete[edit]

The E1 series exists only for historical reasons. The E3 series is rarely used, except for some components with high variations like electrolytic capacitors, where the given tolerance is often unbalanced between negative and positive 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 (310 − 1) ÷ (310 + 1) = 36.60%. 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 likely obsolete.

E24 vs E48, E96, E192[edit]

Since some values in the E24 series do not exist in the E48, E96 and E192 series, resistor manufacturers have added the missing E24 values to some of their 1%, 0.5%, 0.25%, 0.1% tolerance families. This allows easier purchasing migration between different tolerance parts. This type of combination is noted on resistor datasheets and webpages as "E96 + E24" and "E192 + E24".[9][10][11]

Comparison of E24 vs E48 values:

  • matching – 1.00, 1.10, 7.50
  • missing – 1.20, 1.30, 1.50, 1.60, 1.80, 2.00, 2.20, 2.40, 2.70, 3.00, 3.30, 3.60, 3.90, 4.30, 4.70, 5.10, 5.60, 6.20, 6.80, 8.20, 9.10

Comparison of E24 vs E96 values:

  • matching – 1.00, 1.10, 1.30, 1.50, 2.00, 7.50
  • missing – 1.20, 1.60, 1.80, 2.20, 2.40, 2.70, 3.00, 3.30, 3.60, 3.90, 4.30, 4.70, 5.10, 5.60, 6.20, 6.80, 8.20, 9.10.

Comparison of E24 vs E192 values:

  • matching – 1.00, 1.10, 1.20, 1.30, 1.50, 1.60, 1.80, 2.00, 4.70, 7.50
  • missing – 2.20, 2.70, 3.00, 3.30, 3.60, 3.90, 4.30, 5.11, 5.60, 6.20, 6.80, 8.20, 9.10

Lists[edit]

A decade of the E12 values shown with their electronic color codes on resistors.

List of values for each E-series:

  • E1 value
    • 1.00
  • E3 values (>20% tolerance)
    • 1.00, 2.20, 4.70
  • E6 values (20% tolerance)
    • 1.00, 1.50, 2.20, 3.30, 4.70, 6.80
  • E12 values (10% tolerance)
    • 1.00, 1.20, 1.50, 1.80, 2.20, 2.70, 3.30, 3.90, 4.70, 5.60, 6.80, 8.20
  • E24 values (5% tolerance)
    • 1.00, 1.10, 1.20, 1.30, 1.50, 1.60, 1.80, 2.00, 2.20, 2.40, 2.70, 3.00, 3.30, 3.60, 3.90, 4.30, 4.70, 5.10, 5.60, 6.20, 6.80, 7.50, 8.20, 9.10
  • E48 values (2% tolerance) - (see notes in previous section)
    • 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) - (see notes in previous section)
    • 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) - (see notes in previous section)
    • 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

Table[edit]

E3 E6 E12 E24 E48 E96 E192
1.00 1.00 1.00 1.00 1.00 1.00 1.00
1.01
1.02 1.02
1.04
1.05 1.05 1.05
1.06
1.07 1.07
1.09
1.10 1.10 1.10 1.10
1.11
1.13 1.13
1.14
1.15 1.15 1.15
1.17
1.18 1.18
1.20
1.20 1.20 1.21 1.21 1.21
1.23
1.24 1.24
1.26
1.27 1.27 1.27
1.29
1.30 1.30
1.32
1.30 1.33 1.33 1.33
1.35
1.37 1.37
1.38
1.40 1.40 1.40
1.42
1.43 1.43
1.45
1.50 1.50 1.50 1.47 1.47 1.47
1.49
1.50 1.50
1.52
1.54 1.54 1.54
1.56
1.58 1.58
1.60
1.60 1.62 1.62 1.62
1.64
1.65 1.65
1.67
1.69 1.69 1.69
1.72
1.74 1.74
1.76
1.80 1.80 1.78 1.78 1.78
1.80
1.82 1.82
1.84
1.87 1.87 1.87
1.89
1.91 1.91
1.93
2.00 1.96 1.96 1.96
1.98
2.00 2.00
2.03
2.05 2.05 2.05
2.08
2.10 2.10
2.13
E3 E6 E12 E24 E48 E96 E192
2.20 2.20 2.20 2.20 2.15 2.15 2.15
2.18
2.21 2.21
2.23
2.26 2.26 2.26
2.29
2.32 2.32
2.34
2.40 2.37 2.37 2.37
2.40
2.43 2.43
2.46
2.49 2.49 2.49
2.52
2.55 2.55
2.58
2.70 2.70 2.61 2.61 2.61
2.64
2.67 2.67
2.71
2.74 2.74 2.74
2.77
2.80 2.80
2.84
3.00 2.87 2.87 2.87
2.91
2.94 2.94
2.98
3.01 3.01 3.01
3.05
3.09 3.09
3.12
3.30 3.30 3.30 3.16 3.16 3.16
3.20
3.24 3.24
3.28
3.32 3.32 3.32
3.36
3.40 3.40
3.44
3.60 3.48 3.48 3.48
3.52
3.57 3.57
3.61
3.65 3.65 3.65
3.70
3.74 3.74
3.79
3.90 3.90 3.83 3.83 3.83
3.88
3.92 3.92
3.97
4.02 4.02 4.02
4.07
4.12 4.12
4.17
4.30 4.22 4.22 4.22
4.27
4.32 4.32
4.37
4.42 4.42 4.42
4.48
4.53 4.53
4.59
E3 E6 E12 E24 E48 E96 E192
4.70 4.70 4.70 4.70 4.64 4.64 4.64
4.70
4.75 4.75
4.81
4.87 4.87 4.87
4.93
4.99 4.99
5.05
5.10 5.11 5.11 5.11
5.17
5.23 5.23
5.30
5.36 5.36 5.36
5.42
5.49 5.49
5.56
5.60 5.60 5.62 5.62 5.62
5.69
5.76 5.76
5.83
5.90 5.90 5.90
5.97
6.04 6.04
6.12
6.20 6.19 6.19 6.19
6.26
6.34 6.34
6.42
6.49 6.49 6.49
6.57
6.65 6.65
6.73
6.80 6.80 6.80 6.81 6.81 6.81
6.90
6.98 6.98
7.06
7.15 7.15 7.15
7.23
7.32 7.32
7.41
7.50 7.50 7.50 7.50
7.59
7.68 7.68
7.77
7.87 7.87 7.87
7.96
8.06 8.06
8.16
8.20 8.20 8.25 8.25 8.25
8.35
8.45 8.45
8.56
8.66 8.66 8.66
8.76
8.87 8.87
8.98
9.10 9.09 9.09 9.09
9.20
9.31 9.31
9.42
9.53 9.53 9.53
9.65
9.76 9.76
9.88

See also[edit]

References[edit]

  1. ^ "1930 Catalog - Page 139 - Capacitors (Condensers)". Allied Radio. Archived from the original on 11 July 2017. Retrieved 11 July 2017. 
  2. ^ "1940 Catalog - Page 54 - Capacitors (Condensers)". RadioShack. Archived from the original on 11 July 2017. Retrieved 11 July 2017. 
  3. ^ "1930 Catalog - Page 141 - Resistors". Allied Radio. Archived from the original on 11 July 2017. Retrieved 11 July 2017. 
  4. ^ "1940 Catalog - Page 60 - Resistors". RadioShack. Archived from the original on 11 July 2017. Retrieved 11 July 2017. 
  5. ^ "2017 Catalog - Pages 29 to 41 - Passives" (PDF). Jameco Electronics. Archived from the original (PDF) on 11 July 2017. Retrieved 11 July 2017. 
  6. ^ a b c d IEC 60063:1963 - Preferred number series for resistors and capacitors. International Electrotechnical Commission (IEC). 1963. Archived from the original on 11 July 2017. Retrieved 11 July 2017. 
  7. ^ a b IEC 60063:2015 - Preferred number series for resistors and capacitors. International Electrotechnical Commission (IEC). 2015. Archived from the original on 11 July 2017. Retrieved 11 July 2017. 
  8. ^ IEC 60063:1952 - Series of preferred values and their associated tolerances for resistors and capacitors. International Electrotechnical Commission (IEC). 1952. Archived from the original on 11 July 2017. Retrieved 11 July 2017. 
  9. ^ "Standard Values Used in Capacitors, Inductors, and Resistors". Bourns. Archived from the original on 11 July 2017. Retrieved 11 July 2017. 
  10. ^ "D/CRCW e3 - Standard Thick Film Chip Resistors - Datasheet" (PDF). Vishay Intertechnology. Archived from the original (PDF) on 11 July 2017. Retrieved 11 July 2017. 
  11. ^ "TNPW e3 - High Stability Thin Film Flat Chip Resistors - Datasheet" (PDF). Vishay Intertechnology. Archived from the original (PDF) on 11 July 2017. Retrieved 11 July 2017. 

External links[edit]