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PyResistorColorCode 0.1.0

Python module providing some tools to manage IEC 60062 marking codes for resistors.

PyResistorColorCode V0.1.0

The user and API documentation is hosted on the project homepage.

Written by Fabrice Salvaire.


PyResistorColorCode is a Python module that provides some tools to manage IEC 60062 marking codes for resistors.

The associated program resistor-decoder provides a graphical user interface to help user to decode a resistor colour-coding using an inference algorithm. This feature is an enhancement compared to a program like gresistor which is only a colour-coding calculator.

I started to develop this software a day where I had to sort a lot of unsorted resistors in a jumble. Resistors colour-coding using no more than 3 bands (2 digits and a multiplier) are no too difficult to decode when a person is experienced. But for more accurate resistors, it is more tricky. Another difficulty arises when it is difficult to recognise the colour of a band, due to an inappropriate colour contrast or tone. For strange colour-coding we can in last resort use an Ohmmeter to measure the resistance value. But it doesn’t respond to the question what is the specification of this resistor: tolerance, temperature coefficient, etc. For all theses reasons, I developed an inference algorithm coupled to an graphical user interface to help user to decode resistor colour-coding.

Inference Algorithm

The inference algorithm works as follow:

  • code orientation (left-right or right-left) doesn’t matter,
  • unset bands are not take into account,
  • at least 3 colours must be provided: 2 digits and the multiplier,
  • colour band are interpreted by priority as:
  1. resistance value,
  2. resistance tolerance,
  3. temperature coefficient,
  • the resistance value must exists in a IEC 60063 series: E6, E12, E48, E96, E192,
  • the resistance tolerance must be defined if there is a colour band assigned to it.

When there is more than one hypothesis for the given input, the hypotheses are sorted by ascending precision (series).


You can install from Pypy:

pip install PyResistorColorCode

but pip is unable to install PyQt. If you are on Linux then install the corresponding package else download the installer from PyQt download page.

Source Repository

The source code is licensed under GPL V3 and is hosted on GitHub. Also a Python package is available on PyPI. And the relative project page on is located on the ohloh project page.


  • Python 2.7
  • PyQt 4.8

Manual Installation

Alternatively you can download the source from Github or Pypi and run the following commands in a terminal within the source directory:

python build
python install


Set the terminal environment using:


then run the command:


Package for Linux

RPM .spec files are provided for Fedora (up to F18), see spec directory in the sources.

File Type Py Version Uploaded on Size
PyResistorColorCode-0.1.0.tar.gz (md5) Source 2014-04-08 156KB