Introduction: Make a Resistor Reference Card

Picture of Make a Resistor Reference Card

Way back when I very first started getting interested in electronics, and radio shack was more than a mini best buy, I picked up an invaluable learning aid / tool.

It was a simple piece of cardboard with 3 wheels inside of it, dial in the colors and it told you the values of resistors, capacitors, and on the backside 2 scales of inductors! (catalog number 271-1210)

While no replacement for proper education on the subject, it proved itself more than useful, so useful I still own the darn thing to this day 20 + years later, and even mention it in one of my Instructables as "the best darn piece of cardboard they don't make anymore".

The problem with it is, when radio shack changed from Archer brand stuff in brown packages to R (circle) stuff in blue and white packages, and eventually dwindled their electronic supply down to a couple of cabinets from 3 walls of the stuff, this handy device disappeared.

Without getting into too much RS / Tandy / Archer history, I would guess it had not been produced since the mid 1990's ... and thats a shame.

I have been meaning to make my own similar version of the card ever since I started Instructables, but ironically, I was going nuts trying to figure out a cardboard project for the "Gorilla Glue Cardboard Contest"...

Then one night, planning out how to shove a Cmoy amp into a 9volt battery, I was using this thing and all of a sudden all the DUH's came into place!

Welcome to my 6th Instructable.

Step 1: Tools and Materials

Picture of Tools and Materials

Tools:
Computer (which if your viewing this I have to assume you have access to at least one)

Color printer, one that you can feed the paper from the back in a direct line to the print heads and out again (I used my wifes horrid 5+ year old HP all in one inkjet), even if you have a printer with a 2 stroke weed eater motor attached, curling the cardboard around the typical paper feed rollers will ruin it

Ruler / Straight edge

Sharp scissors

Xacto / Hobby / Scalpel / Matt knife with a fresh sharp blade

Black felt tip marker (sharpie is what I used)

Wire cutters

Materials
Thin cardboard, mine was cut out of a thick presentation folder / box, but the same thickness is often found in packs of plain underwear type T-Shirts

1 inch long "paper fasteners", thats the best name I can seem to find for them, they are a thumb tack sized doo-dad with 1 inch long thin metal strips on one side, put them in a hole and bend the strips over to hold paper. They are really common, I found mine at K-mart, in a pack o 100 for $1.29, but anyplace you can find basic office supplies should have them. Just for reference heres a link to some more fancy ones on staples.com

http://www.staples.com/OIC-1-Brass-Fastener-3-8-Head/product_378814?cmArea=SC1:CG1036:DP4378:CL163582:SS975752

Step 2: Design of the Card (part 1)

Picture of Design of the Card (part 1)

I guess I could have just ripped apart my radio shack card and scanned it, and called it an Instructable ... but thats no fun (and possibly breaching copyright).

The original radio shack card shows color codes for resistors, capacitors, and inductors, but to be totally honest, I have never used the inductor side, and rarely have I ran across color coded capacitors (in some vintage radio equipment maybe), so I choose to not bother replicating those, My card will do resistance only.

Also the radio shack card, in accordance with standard resistor color codes shows gold (/10) and silver (/100) on the 3rd band, again something thats not really likely to come up in hobby electronics, so due to part lazyness and part "how am I going to print metallic colors on a inkjet" those 2 are not included in the multiplier section.

The card can show values from 10 ohms to 99 meg-ohms with no confusion , and that should be just fine for most applications, heck the Radio Shack card only does 99 meg- ohms ...

Now on to the design but!

IF you have no interest in how I actually made the graphics for the card, and just wish to print out an image and assemble it please skip ahead to step 7

Step 3: Design of the Card (part 2)

Picture of Design of the Card (part 2)

Now this Instructable is not really meant as a guide for Inkscape so I will only briefly touch on the basics of how I made the layout.

The first thing to do is get some basic measurements of the original, which is 4 inches long * 2 inches tall, and contains 3 2 inch diameter wheels.

Using those dimensions its time to hit the computer and fire up Inkscape (or Adobe Illustrator, or Corel draw or any other vector type drawing program), and lay out some guides.

Next, off to the side I want to lay out some more guides for the wheels, basicly making a 2 inch * 2 inch square, also on the part used for the wheels I marked the centers of the X and Y axis, and on the X centerline I added 2 more guides on either side about 1/8th inch from the centerline.

I then drew a 2 inch circle using the guides outlined only, copied and pasted it and shrunk it down to about 1.75 inches, in order to evenly divide the circle into 10 even sections I drew 2 pentagons, and flipped one upside down and scaled them so that the point of the pentagons were touching the inside circle.

I then drew a 1/4 inch solid (with no outline) circle, and placed it in between my center marks on the inside of the inside circle at the 12 o clock position, next I placed a 0 (zero) on the outside of the inner circle at the 6 o clock position.

Step 4: Design of the Card (part 3)

Picture of Design of the Card (part 3)

I went ahead and copied and pasted the black dot and the zero off to the side, to make things go abit faster.

Next I selected the black dot, and its zero and the outer circle and rotated the whole thing clockwise to the next point on the pentagons.

I then copied and pasted the black dot and zero thats now on the side of the drawing back into the center position on the circles, changed to brown and its value to 1.

keep doing this until you have all the colors and values all the way around the circle.

black = 0
brown = 1
red = 2
orange = 3
yellow = 4
green = 5
blue = 6
purple = 7
gray = 8
white = 9

Finally put a 1/8th inch black dot in the center of the wheel

Select everything you just did, group it together and move both out of the way for now.

Step 5: Design of the Card (part 4)

Picture of Design of the Card (part 4)

The next wheel we need to make is really the 3rd wheel, its the same process but instead of 10 segments we only need 8.

This is fairly easy to eyeball using the center point guides so thats what I did, the process is the same as before, place color, and value, then rotate and keep going until your done.

The colors and values on this wheel need to be

black = .0
brown = 0
red = 00
orange = 000
yellow = 0,000
green = 00,000
blue = 000,000

And don't forget to mark the center of the wheel with a black dot group everything on this wheel together and move off to the side

Step 6: Design of the Card (part 4)

Picture of Design of the Card (part 4)

Now we can return to the first set of boxes we made, grabbing our first circle line the wheel up against the edge of the card, and make it poke out of the top abit, once you have it lined up place another black over the black center dot on the wheel to mark the card.

Next draw a circle over the color circle at the 12 o clock position on the wheel, and a box around the number at the 6 o clock position, its now a good idea to rotate the circle to make sure all the numbers and color dots line up with what will be our windows in the final product.

Once we have everything nice and pretty, select everything you were just working on, copy it and paste it, position the copy where the outside of the second wheel is just to the left of the center dot on the first wheel also add another dot on top of the center dot of that circle to mark the hole on the card.

The 3rd wheel (the one with only 8 segments, or the second one we had to make) needs to be just to the left of the center dot of the second wheel, similar to the first wheel we will need to make a new box for the larger values, and rotate the whole thing to make sure it all lines up with the "windows", and add a dot on top of the center dot to mark the 3rd center hole of the card.

You will find that the third wheel sticks out of the side of the card, so what happened? When you use outlined shapes in most programs half of the outline is on the inside of the shape, the other half is on the outside, so our wheels are like 2.1 inches in diameter and our boxes are like 3.9 if your going by the outlines.

Don't worry were not precision machining something that our life depends on, just expand the side of the card a little bit, and since we will be cutting this all out by hand a little wiggle room is nice to have.

I then selected the whole lot, copied and pasted it in some open space flipped it horizontally and put it below for the backside, then deleted everything except the 3 center dots so we know where to cut on the back too.

Finally I moved the wheels back out of the card onto some open space, you can now see the 6 windows and the 6 hole markers we need to construct the card, along with the wheels in some free space, almost ready to print.

Step 7: Design of the Card (part 5)

Picture of Design of the Card (part 5)

Saving the file as a standard *.svg file (found attached in a zip below) I opened it back up in the gimp and started to "paint" the graphics for the card

Hopefully at this point in between my screen shots and loose instructions you should be able to construct this entire thing totally from scratch. BUT if you just want to change the graphics to your school, business, lab or whatever you should grab one of these files so you can just paint it

The gimp (and many other programs) can read svg files with no problem, but if your paint package does not, I have also included a png file that all image editors will open

For my card I choose to go with an Instructables.com design, featuring the site logo, the robot and color layout, and that is also included in the zip file

So download and get ready to print!

Step 8: Printer's, Man I Hate Printers

Picture of Printer's, Man I Hate Printers

The only printer we currently own is a old, cheap hp all in 1 inkjet, on the back of the printer there is a plastic panel that can be removed to pull out paper jams, but with that off you can also run heavy stock like cardboard, cardstock or photo paper from the back in a direct line out to the front

your printer will most likely differ but something along those lines is what we need, a way to feed paper from the back so this heavy cardboard does not have to go around the rollers.

On my particular piece of "magic" its not really designed to do this, so in order to get it to work I had to have paper in the front tray or it would trigger a jam condition.

Then I had to kinda push the cardboard in, then it would spit it out 4 or 5 times, and Finally print on it.

It took me about 15 min to get it to print the first time, but it started going at an angle at the last moment and skewed the card

The second time it did not take as long, but then my wife said, "you know the text on the back is backwards" and sure enough it was

SO about an hour of listening to this thing clunk about, clearing its software of paper jams, running the cardboard tru the dumb thing 4 or 5 times each print and really cheesing off the wife, (cause it was sitting about a foot from her head while all this was going on) I finally got the thing to print the card straight and proper on my last piece of scrap cardboard.

Depending on your printer and your penitence maybe your luck will be better, but In the end it DID do it and saved itself from me going "Office Space" on it

Worst case and you cannot print directly on the cardboard, you can always just print it out on paper and then glue the paper to the cardboard (but I was committed to the idea)

Step 9: Print It

Picture of Print It

This is pretty simple you want to print out the image provided in the zip file

you do not want any scaling rotation or anything, just plain and simple print

for you windows users out there you can use the picture and fax viwer included in windows and the print wizard thats in there

set your printer to its best quality, get the cardboard ready and let it go

Step 10: Cut It Out

Picture of Cut It Out

Using your sharp scissors cut out the card and the 3 wheels following the outlines.

Next using your knife cut out the centers of the 2 wheels, and the 6 black dots on the card.

Then cut out the "windows" in the cards, when it came to the 3 circular windows that the colors will show tru I kinda cheated and use a single hole, hole punch.

Go slow and take your time, make multiple passes with the knife to avoid slipping.

After cutting everything out I went around the edges with a black felt tip pin, to color the white edges but to also cover up where the bad printer + antialasing did not leave the outlines good and dark.

Step 11: Assemble

Picture of Assemble

Start by flipping the body of the card upside down, center your ruler over the middle part of the card and use it as a break.

bend upwards in a 90 degree angle, then remove the ruler, continue bending the card until both halves meet.

Next get your first 10 segment wheel and line it up inside of the card where the center hole of the wheel lines up with the leftmost hole in the card, and run a paper fastener through it, repeat for the second 10 segment wheel for the middle hole, and the 8 segment wheel on the rightmost hole.

Once all the wheels and fasteners are in place use your wire cutters to trim the ends of the fasteners down to about 1/4 inch long, then bend them down.

Make sure they are fairly tight, but not so tight that the wheels will not move, and enjoy!

Comments

hfxmakerspace (author)2017-03-19

I used 1/8 eyelets for the axles and added our Makerspace's logo. I lasercut the holes and card outline. I will likely redesign it a bit to get 2 cards per sheet, then make a bunch to give away at our classes, etc. Thanks for sharing your work!

nerd7473 (author)2013-10-06

does RadioShack still sell the cards?

osgeld (author)nerd74732013-10-07

nope

J-Five (author)2012-02-10

On a Commodore 64 simulator I made a program that asks if it's a 4 or 5 band resistor. You type in the color, then it matches it witch the right color (i.e. green then value would be 5) for the rest of the significant bands. Then it does the same thing for the multiplier band. (I.e. blue would be 10^6). And finally it asks for the tolerance value, and calculates the lowest to highest possible value.

Anonyomus Duck Ninja (author)2011-03-28

BTW Its a split pin. LOL

MacabreRob (author)2011-03-18

Very nice. Very handy. Just printed it out at work (they have the color printer) and going to assemble it tonight. I was teaching my son some basic electronics a couple weeks ago for a Boy Scout merit badge and had him looking up the color values from an index card taped up on the back of my electronics kit box. This will make it easier.

I just hope I don't lose it... :-)

mab0085 (author)2011-02-12

good one

wout smeets (author)2010-12-11

it works graet

thanks bro

osgeld (author)wout smeets2010-12-11

Your welcome!

zack247 (author)2010-11-10

THANK YOU! i have been killing myself having to figure out resistors! now thanks to this i can easily figure it out without having to search up a resistor color code chart on the internet.

osgeld (author)zack2472010-11-10

your welcome, and the more you use one of these the less you need to

zack247 (author)osgeld2010-11-10

yes, especially when im away from the internet! 5*s

DocAmpuT (author)2010-10-25

I was in dire need of using the like resistor calculator after our 9th grade teacher showed us those things a couple of years after teaching the politically incorrect version of the color bands memory aid that my father had used also.

The prime reason I did use the calc thing from Radio Shack was because I was lazy and it was a bit quicker than figuring values in my head. ** grin **

Oddly enough, I still have that thing in workable shape sitting in my office. Probably because it got a break after one of the first programs I ever wrote for any home computer served the same purpose in letting me put the bands in and having it quote a calculated resistance for me on an old Commodore Vic-20.

Did you resistance calculator look like the one in this uploaded image I'm including?

osgeld (author)DocAmpuT2010-10-26

Yes thats it!

you can see mine in a picture on step two, and I still have mine today also

fundash (author)2010-08-22

I must make this!

purposelycryptic (author)2010-06-14

I realize no one has posted here in almost a year, but since I just now came across this, and have been tearing my hair out over resistors for ages, I figured I'd say thank you:). Just now finished mine, I used photo-paper instead of cardboard, so it's probably slightly less sturdy, and used rivets to fasten it. Now I'm off to make a second one, since the first was more of a hasty prototype, as I was unsure if the wheels would still move after being riveted (They do). Thanks again!

kroq-gar78 (author)2010-04-23

relatively simple project. going to make one as soon as possible!
awesome idea!!

lunchboxslayer27 (author)2009-12-04

i just finished mine now, it oozes amazingness, lol

J-Five (author)2009-11-27

I am impressed!!!!

Osgeld you are a genius!!!

Very clever

mischka (author)2009-11-26

this is very useful, thanks a lot

osgeld (author)mischka2009-11-27

Thanks, and your welcome

jgscott987 (author)2009-08-13

I have many fond memories of the cardboard resistor wheels. I've found that a simple table is a lot easier and more straightforward however. I keep this chart above my bench and I can refer to it without even taking my hands off what I'm doing.

Goodhart (author)jgscott9872009-10-31
That is great, thanks. I have troubles with oranges and reds, and although they are clear on the chart, on a resister they sometimes are much less so.
 
osgeld (author)Goodhart2009-11-01

agreed

Goodhart (author)2009-10-31
Very nice.   At my workbench, I use a chart (as someone else mentioned) but when away from my bench, this would be a VERY valuable tool.
 
5tgb6yhn (author)2009-10-31

I used 1/4" brass grommets instead of brads for a cleaner look.  A lot stronger too.  Grommet kits, made by either Stanley or General, are readily available at most hardware stores.

mightywombat (author)2009-08-15

I have a friend who is colorblind, and now I kind of want to make him a little scanner device that can read the colors off a resistor and tell him what the resistance is... Hmm... *pondering*

ohm meter?

froggyman (author)joejoerowley2009-09-22

nawh, that would be too simple...

mightywombat (author)froggyman2009-09-22

Exactly!

froggyman (author)mightywombat2009-09-24

Why would you bother making something to read the colors off a resistor only for it to change it back to its resistance, or build something to read the colors and then tell him the colors so he can re-decode them? And that would require a lot more electrical work and be less accurate than a ohm meter. Also, what if he is working with a SMD resistor, then the color reader thing woulding work... (well, neither would the card here, but the ohm meter would read both through hole parts and SMD parts, resistance wise atleast) Or better yet, get a a MULTI-meter

Chromatica (author)mightywombat2009-09-22

hey so am i instructables is red to me

talk2myshirt (author)2009-08-31

Great little helper - exactly what I was looking for :)

Dipankar (author)2009-08-25

Sharing this with us is really great. It comes in very handy. Thanks.

osgeld (author)Dipankar2009-08-27

Thank you everybody for your kind comments!

knexsuperbuilderfreak (author)2009-08-23

ausome nice idea but what did you use to make the card

The card itself is made out of thin non corrugated cardboard, the graphics were done on Inkscape + The Gimp

static (author)2009-08-17

Far out man, slick work. I can see some one making a super sized version for wall art in the shop. 5 stars.

sharlston (author)2009-08-14

theres some free software that has a resistor thing for coputers :)

tundrawolf (author)2009-08-13

That's pretty slick! good idea, thanks! I'll give you $5 to print out another piece of cardboard and send it to me. Just kidding! :)

3vilnat3 (author)2009-08-13

This sounded like a good idea for college, so i made one in my college colors. i think it turned out really well. great idea!

osgeld (author)3vilnat32009-08-13

looks good! (I was wondering when I would see others artwork on this)

NEIN (author)2009-08-13

How awesome would this be as a BUSINESS CARD!!

conrad2468 (author)2009-08-13

great instructable, but i prefer the ipod app just cause its an ipod app.....worth 5 stars though!!

simplebeep (author)2009-08-13

I love this. I can never remember what those darn transistor colors mean; and even if I could, I would be constantly second-guessing myself.
It's so simple, yet such a great idea!

pravardhan (author)2009-08-13

My 1st PUC (Class - 11) teacher taught it as:
"B.B.Roy Of Great Britain had a Very Good Wife"

Very Good Idea, But where to find a Colour Printer. I have two B/W Laser Printers!!!!!

5 Stars from me. -

crazzzy1 (author)2009-08-13

lol 660 so close

pancho del rancho (author)2009-08-12

foo its been on the web for like 5 days and its featured already thats smart

D.L.H. (author)2009-08-12

The idea is very cool and helps in the long run.Glad that someone made this.

mdog93 (author)2009-08-11

Could i scale it down to fit between two credit cards (old gift cards or something similar)? mdog

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