Blue Rectangles

Why do some parts, like zener diodes and switches, have blue rectangles where the part symbol ought to be?

I’ve always had this question. Hopefully someone can throw light on this.

I believe the blue rectangle is a placeholder for “Digi-Key Catalog” parts that do not have a schematic symbol pre-assigned in the “Digi-Key Catalog” parts library.

When I encounter a part like this, instead of using the specific part, I use an appropriate symbol from the “Schematic Symbols” library instead of the “Digi-Key Catalog” part.

Then I use the “Catalog Assign” button in the “Part Properties” tab to assign the Digi-Key part information to the generic symbol.


Oh! Thank you very much.

It surprises me that even zener diodes do not have symbols assigned.

Even more surprising is that some have a basic diode symbol instead of one of the three different common Zener symbol variations.

Being only a user here I have no inside knowledge, but I’d guess as they went along trying to have symbols for their whole catalog of over 14.5 million parts they rapidly hit problems that were not solvable in any economically practical way. Given that there is no single standard for schematic symbols and Digi-Key now supplies a global market rather than just North America, I can imagine the database programming solutions can get way out of hand quickly.

I have no doubt about what you are suggesting. However, DigiKey is a world-class company. They have always accomplished things that no other company has been able to do (until the last few years). They absolutely have to resources to provide symbols for zener diodes. We’re talking basic parts. Other schematic providers have been able to do so.

The most economically viable solution is to open up the database to allow users to provide parts associations. Is that option available now?

I very much want a good schematic capture program. While I realize that most of them, such as Kicad, are good, the learning curves for the parts libraries are steep. My guess is that once you learn how to use one library creation tool, the rest will function similarly.

I’m not critical. I’m hopeful.