Working with the E-series of preferred numbers used for electronic components, such as resistors and capacitors

Project description

The E-series is a system of preferred numbers used with electronic components such as resistors and capacitors. For example, the E6 series contains six values (10, 15, 22, 33, 47, 68) which cover a one-order of magnitude range of values (one decade) from 10 to 99. These base values repeat again to cover the next decade from 100 to 999, as 100, 220, 330, 470, and 680.

This eseries library is useful for selecting values from the standard E3, E6, E12, E24, E48, E96 and E192 decades.

Python Interface

For example, to find the nearest E24 value to 319 use:

>>> from eseries import find_nearest, E24
>>> find_nearest(E24, 319)
330

To find the next value greater-than or equal-to 184 in the E96 series use:

>>> from eseries import find_greater_than_or_equal, E96
>>> find_greater_than_or_equal(E96, 184)
187


To find a few values around the specified value, use:

>>> from eseries import find_nearest_few, E24
>>> find_nearest_few(E24, 5000)
(4700, 5100, 5600)


Command-Line Interface

There’s also a handy command-line interface. Run eseries --help to see a list of commands:

$eseries --help eseries Usage: eseries [options] <command> [<args> ...] Options: -h --help Show this screen. -v --verbose Use verbose logging Available commands: ge gt help le lt nearby nearest range series tolerance See 'eseries help <command>' for help on specific commands. To find a nearby value, use: $ eseries nearest E24 37726
39e3

If you prefer an SI exponent symbol, supply --symbol or -s:

$eseries nearest E24 37726 -s 39 k To show values around the given value, use the nearby command:$ eseries nearby E48 52e6 -s

48.7 M 51.1 M 53.6 M

To show the smallest value greater than or equal to the given value, use the ge command:

\$ eseries ge E48 52e3 -s
53.6 k

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