Basic Examples (3) 

Find the E6-series value closest to a desired value:

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Find the E192-series value closest to a desired value:

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Find a three element solution in the E6-series for a desired value:

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Scope (4) 

An optimal solution might not always be found:

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Multiple solutions with equal performance can be found:

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Some elements might be superfluous (neutral element in serial combination is 0) in series:

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Some elements might be superfluous (neutral element in parallel combinations is ∞) in parallel:

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Specifying All as the first argument always returns the full specified series-factors:

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Options (5) 

Some optimal values might only be found if "ExtraExponent" is increased:

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Increasing "ExtraExponent" also sharply increases computation time:

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Setting GenerateConditions to true yields all solutions to all element combinations sorted by accuracy:

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Allow smaller element values with "MinValue":

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Allow bigger element values with "MaxValue":

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Applications (2) 

Some voltage references need very specific resistance divider ratios to get to a desired output voltage. One such known ratio, for example is 13:1 for LT1000 style references. While 1kΩ resistors are plenty available with sub-ppm temperature slopes, 13k is way harder to get because low-ppm resistors are usually available only in low E-series like E12 or even E6/E3. A resistance of 13kΩ is however easy to compose with two E12, three E6 or four E3 resistors instead:

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The configuration strings can also be converted to expressions and used with Around to estimate uncertainties of the dividers for all resistance tolerances being 0.1%. This shows the first E6 solution to be the most precise:

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Properties and Relations (1) 

The user can supply a custom series as a list:

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Possible Issues (1) 

Non standard E-series specifications will yield a warning but will work:

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Neat Examples (2) 

Compare three E3 elements with two E6 and one E192 element all with 0.1% tolerance between 1k and 2k:

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The E-series are uniformly distributed in log-space:

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