Entering resistor values

I would like it very much if when I enter a value for a resistor the symbol on the schematic is updated to include the correctly placed coloured bands :crazy_face:

That might be problematic:

  1. Color banding depends upon whether you are using 5% or 1% resistors. There are other tolerances also but 5% and 1% are the most common in axial leaded resistors. Regarding tolerance only, it is perfectly OK to substitute a tighter tolerance in place of a wider one. I would not recommend replacing a 10% ceramic composition resistor (unusual type for high peak pulse duty) with a film type, regardless of its tolerance.
  2. Axial leaded color banded resistors are partially (not completely) obsolete. They are mostly replaced by SMT resistors. SMT is highly recommended, even for people like me whose hands are not the most steady. SMT resistors do not have color bands.
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The maintainer of the 3D viewer (maui?) once showed screenshots of experimental mods for colour banded resistors. I don’t think parametric models have made it into the main branch. It was in response to a t-i-c post of mine asking for 3D models of LEDs in colours other than red. Parameterised so not one model for every colour.

Then there was this project on Hackaday: The Great Resistor | Hackaday.io which might make a geeky coffee table piece.

I know it’s not serious but I don’t think it’s useful to have the colour codes on the schematic. When I go looking for a 68k THT resistor I look at the box or bandolier label, not for a blue-gray-black-red resistor, which is too small to read without a magnifying glass anyway.

you may lookup the color codes with Kicad invoking the “Calculator Tools” in the “Color Code” tabulator

In about 1970 as a college sophomore in EE, we were told to learn the resistor color codes. In EE there is not so much rote memorization but that was one exception. These days I wonder whether new EEs need to learn that. I think I have encountered some youngsters (any EE under 40?) who do not know it. Regardless of my advice above, leaded components such as axial resistors are particularly useful for kluges (hand wiring on perf board or even with no board) or for rework. I hand wired an e-load during the 1990s. It is hand wired on perf board and with sheets of aluminum for heatsinks. I am still using it.

I was taught the non-pc version (also in the 70s):
Bad Boys Rxxx Our Young Girls But Violet Gives Willingly.

And you can’t just put the color codes on axial resistors, without also putting the eia-96 three-letter codes on smt resistors :slight_smile:

I learned the colors at the beginning of the 80s and indeed all of my younger colleagues perceive this as some kind of oddity :crazy_face:.
This capability remains until today to the point that I am sometimes unconsciously relating colors to numbers though I am mostly using SMD-Rs today (1206 due to optical reasons).
But - color codes on THT-Rs would be sooo nice ! :upside_down_face:

What about THT capacitors?


I miss the days of THT capacitors cunningly disguised as liquorice allsorts.


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The last thing you want is colour codes on the schematic

Perhaps not in the schematic, but in the 3D viewer and in the html BOM plugin.

Here is a color-code and alphanumeric-code calculator that’s a kinda-fun throwback to 90’s html typically only seen today on ham radio sites:

color-code calculator

And the basic resistor color code still lives on in idc cable and all those ubiquitous dupont jumpers (where it starts at 1=brn, and 10=blk):

I just commented about an addon for FreeCad which makes 3D color bands on resistors.

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