Scheme module that allows to work with E Series preferred values.
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README

  --------------------------------
    E-Series Tools for GNU Guile
  --------------------------------

The E-Series are series of preferred numbers, commonly used to specify electro-
nic parts; mostly resistors, inductors  and capacitors. This library implements
two kinds of lookups: a) Given a value,  look up that value in all E-series and
return the values  surrounding the desired value; and b)  Given an integer that
identifies an E-Series  and a desired value, return combinations  of two parts,
that approximate the desired value as closely as possible.

For ease of use, the library impements the (e-series) module, that implements a
set of frontends (‘resistor’, ‘inductor’ and ‘capacitor’), that can all be used
in precisely the two ways described above. Examples:

(capacitor #e910e-6)
 ---------+--------------------------+-------------+--------------------------
  Series  |           Below (Error)  |      Exact  |           Above (Error)
 ---------+--------------------------+-------------+--------------------------
    E3    |  470.000µF  (-4.835E-1)  |             |  1.00000mF  (+9.890E-2)
    E6    |  680.000µF  (-2.527E-1)  |             |  1.00000mF  (+9.890E-2)
    E12   |  820.000µF  (-9.890E-2)  |             |  1.00000mF  (+9.890E-2)
    E24   |  820.000µF  (-9.890E-2)  |  910.000µF  |  1.00000mF  (+9.890E-2)
    E48   |  909.000µF  (-1.099E-3)  |             |  953.000µF  (+4.725E-2)
    E96   |  909.000µF  (-1.099E-3)  |             |  931.000µF  (+2.308E-2)
    E192  |  909.000µF  (-1.099E-3)  |             |  920.000µF  (+1.099E-2)
 ---------+--------------------------+-------------+--------------------------

(capacitor 12 #e910e-6)
 ------------+-------------------------+-------------+-------------+-----------
    Desired  |         Actual (Error)  |     Part A  |     Part B  |  Circuit
 ------------+-------------------------+-------------+-------------+-----------
  910.000µF  |  909.091µF (-9.990E-4)  |  1.00000mF  |  10.0000mF  |  series
  910.000µF  |  917.647µF (+8.403E-3)  |  1.20000mF  |  3.90000mF  |  series
  910.000µF  |  902.000µF (-8.791E-3)  |  820.000µF  |  82.0000µF  |  parallel
 ------------+-------------------------+-------------+-------------+-----------

To run the test-suite of the library, the following additional dependencies are
required:

    https://github.com/ft/scm-test-tap
    https://github.com/ft/test-dispatch