Check out the resistor color code reference cards I just whipped up. I was inspired by the PCB versions that Octopart has been crowdfunding this week. Those didn’t have the information I would normally be looking up, so I decided to whip up a few of my own and put them out there for inspiration or for you to print yourselves.

The story behind this is that we got several tips about the Octopart cards. Don’t get me wrong, It’s pretty cool to have a PCB refcard. But the information on the front is just the color code itself (three times). The back is a set of surface mount footprints. I don’t find those footprints useful unless its a way to test out custom outlines I designed myself. If I were to order something like this I’d lean more toward the µRuler which [Dave Jones] designed and recently did a small-run open order. I very nearly pulled the trigger on that one. Maybe next time.

Why let the information itself spoil the fun? I got to thinking about stuff I look up a lot. The resistor color code chart is always nice to have on hand, so I included that. Tolerance is one thing I just don’t have memorized (except for the gold 5% band, of course). I also like to look up some SI units to make sure I’m doing my math right. The four most common for me are included on the front just below the Ohm’s Law equation.

On the back is a cheat sheet for reading surface mount resistor codes. [Mathieu] already mentioned that codes with ‘R’ in them can sometimes include a multiplier. Oops! Next to that is a three digit capacitor code reminder which I almost always end up looking up. The power equation is one that I pretty much always know, but hey, there was space for it.

Make one of your own

I whipped this thing up in under an hour using The Gimp. Check out the XCF files, along with the PNG exports shown above (these actually have transparent backgrounds), and the PDF contact sheets I printed for the project. They’re up on our Github repo. I decided to try two different background colors. I’m a fan of the bisque shown above, but also ran half of them in white.

Color prints and laminating sheet Color prints cut and aligned for lamination Laminated cards after being cut apart

I went with my local Fedex Kinkos print shop. I was able to upload the PDF files in advance. They printed two double-sided copes (one of each color) for me. I feel that the $2.91 cost of this is a steal because it means I can get away with a super-cheap black and white laser printer at home. When I picked them up I also used their paper cutter to separate the cards from the sheets. After using the paper cutter’s grid table to align the cards I laminated twelve at once using an 8.5×11 laminating sheet. The finished cards were cut into singles using the same paper cutter. Lamination was $2.10, bringing the total project to $5.01 — that’s 42 cents per card which is a big break from the $9 the Octopart version is asking.

Of course if you want this on a PCB why not use spray adhesive to affix it to some copper clad, then top coat it with clear acrylic spray. Maybe that just sounds easy to me because I actually have all of those things on hand.

If you make your own reference cards we want to see them. Post them below (actual cards you’ve made… no mockups!). I recommend posting your picture to imgur and using HTML img tags in your comment. This should be fun!