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Color Code Decoder

A table with color abbreviations used for resistors.

    This solver decodes a resistor’s color bands. If you deal with this often, you might be better off reading the article Resistor Color Codes that discusses how it is done. With a little help from a mnemonic and a some practice, reading color codes is straight forward.

    This solver takes a different approach to entering the colors than most decoders. Rather than click a bunch of buttons, or select from a number of different menus, you type in the color values. Once you get used to it, it is a quicker than using drop down menus particularly if you are sorting though a lot of resistors.

    Resistor are marked with four, five, or six color bands. Some very old, now obsolete, resistors are marked with three color bands. If your resistor has three or four bands, you must enter a minimum of three colors. If your resistor has five or six bands, you must enter a minimum of four colors. When in doubt, simply enter all of the colors. NOTE: If you have a resistor with five or six bands and one of the bands is gold or silver, you MUST enter at least five bands to get the correct value.  If you are unsure, simply enter all of the bands.

    Colors can be entered using the full color name (for example “red”), a shortened abbreviation (in this case “r”), or the EIA abbreviation ( “rd”). After you type the colors or its abbreviations in the field, click solve. The graphic above the solver provides the available abbreviations.

    For example, suppose you had a resistor with four bands, three for the value and one for the tolerance. The resistor’s colors are yellow, violet, and orange followed by a gold band. You can type in the full color name in the field (yellow violet orange), the short abbreviation (y v o), or the IEC color abbreviations (ye vt og). For the optional tolerance you can enter gold, go, or gd. With the colors entered, click the “Solve” button.  If there is a band after the tolerance band, you must enter the tolerance band.  The easiest thing to do is enter all of the bands on the resistor and let the solver sort it out.

    On some resistors, it is hard to tell which end to start reading from. The solver lists if the resistor you entered is a standard value or not. If it is not, the odds are you entered the value backwards (you read it from the wrong end) or you got one of the colors wrong.

copyright © 2021 John Miskimins


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