Preferred number#E series: Capacitors and resistors

An E- series is a standardized sequence of property values ​​of electrical components. The values ​​of the E- series arising from the Renard series. Commercially available resistors, capacitors or coils usually have nominal values ​​of a E- series. An E- series covers the range of values ​​down so that the ratio of successive values ​​is as large as possible. In addition, the values ​​are chosen so that a repeat of the digits in each decade.

The standard DIN IEC 60063 seven E- series are defined: E3, E6, E12, E24, E48, E96 and E192. Here are the number of behind the E, how many values ​​on the series within a decade. The standard came in December 1985 under the title preferred series for the nominal values ​​of resistors and capacitors in power. It is, in substance consistent with the international standard IEC 60063, 1963.

Calculation

The number of E- series describes the number of denominations within a decade. The first row is E3 with three values ​​per decade. The cards of the larger series has twice as many nominal values ​​per decade. Other rows are E6, E12, E24, E48, E96 and E192. In the E- series, the values ​​are distributed is not linear but logarithmic within a decade. The individual values ​​are within an e- series, by the same principle as the Renard series, described by the following mathematical result:

The terms of the sequence are rounded to three significant digits and that also arise in the ranks E3 to E24 and the E48 two rows to E192 between adjacent sequence elements minimal differences. The cards of the precise resistance range is obtained by doubling the number and halving the tolerance. The higher E series each containing all the values ​​of the child rows.

Since the series E3, E6, E12 and E24 in 1948 and 1950 and thus IEC 63 were set before the emergence of standard DIN, search in the E24 series not the rounding rules, the values ​​from 2.7 to 4.7 and 8.2 what has been changed but not more due to the large spread.

Example

The series resistance E3 has three resistance values ​​per decade. Therefore, the following applies: n = 3

Thus arise from the decade:

It is seen that the value per step always (rounded ) increases by a factor. Since the E3 series consists of only three values ​​within a decade, the calculation is therefore at an end; The next numbers are 10, 22, 47, etc..

Values

Following the committed value of the decade are listed from m = 0:

Tolerances

The greater the E- series, the lower the tolerances of the components must be, as these values ​​might otherwise adjacent superimposed:

In the standard, but only the tolerances for the series E3 to E24 and the maximum permissible deviations are indicated. For the production in particular of the unbalanced resistance resulting from the contacting tolerances that any values ​​can be assigned to resistors produced and sold a value.

In fact, the values ​​of the corresponding rows are also closer tolerances available. Good available is the series E12 with 1% tolerance and the series E96 with 0.1% eg resistors.

Demarcation

Decadal voltage divider can not be realized exactly with individual resistors of the E- series. Therefore, for this purpose there different series resistance, eg with the numerical values ​​1, 9, 99, 999 combinations are available, such resistance in particular, with coordinated temperature and voltage coefficients, in order to realize a voltage divider to whose division ratios are defined much more accurately than the individual resistances.