Introduction: Resistor Color Wheel Tool

I made this paper reference tool to help us find the right resistor without having to look it up online. It's portable, colorful, and makes me happy.

Tools required:

(printer and glue stick) or (protractor and compass)

pencil with eraser

ball point pen

stapler

hole punch

scissors

ruler

crayons: black, white, grey, purple, blue, green, yellow, orange, red, brown

Materials required:

white cardstock paper or standard printer paper and thin cardboard from the recycling bin

brad fastener or a paperclip with a small bead

Step 1: Print or Draft 3 Circles

If using a printer: Print one page of the Resistor_Color_Wheel.pdf on cardstock. If you don't have cardstock, print on plain paper and glue the printout to thin cardboard from the recycling bin. We used a cereal box. :)

If using a protractor and compass:

Draw circles and mark the centers. The exact sizes can vary. Here are the dimensions of a set I made.

  • large circle (14.5 cm diam)
  • middle circle (10 cm diam)
  • small circle (5 cm diam)

In all 3 circles, use a compass to draw ten equal segments, 36 degrees each.

In the middle and large circles, draw two more circles around 1.5 cm and 3 cm from the edge. Color the outermost ring segments clockwise by color order: black, white, grey, purple, blue, green, yellow, orange, red, brown.

In the small circle, draw one circle around 1.5 cm from the edge. Color the center segments clockwise by the same color order.

Step 2: Color Code

In the large circle, write the multiplier in the second ring and fill the outermost ring segments with the corresponding color. Do this in clockwise order.

x 1 ........... black

N/A ........... white

x 100M ...... grey

x 10M ........ purple

x 1M .......... blue

x 100K ........green

x 10K ..........yellow

x 1K ............orange

x 100 ...........red

x 10 .............brown


In the middle circle, write the number in the second ring and fill the outermost ring segments with the corresponding color. Do this in clockwise order.

0 ........... black
9 ............ white

8 ............ grey

7 ............ purple

6 ............ blue

5 ............ green

4 ............ yellow

3 ............ orange

2 ............ red

1 .............brown

In the small circle, color the center segments clockwise and write the number in the outer ring. Use the same numbers and corresponding colors as the middle circle.

Step 3: Cut Out Disks

Cut out all three disks and poke a hole in the center with a ball point pen. Wiggle around the hole until it is wide enough for a brad fastener to turn. Stack the disks on the bard fastener with the smaller disks on top. The color bands and blank number areas should be visible on each disk. Dismantle the assembly and use a hole punch to create semi circle holes along the circumferences in between colors. Later you will use these divets to spin disks with your fingers.

Step 4: Make a Mini Folder

Cut from cardstock or thin cardboard a square (15 cm x 15 cm) and a rectangle (15 cm x 6 cm). Find the center of the rectangle and square by drawing two straight pencil lines from the corners. At the intersection of the straight lines, poke holes and re-stack all the parts on the brad fastener with the square on the bottom and the rectangle on top. Erase the diagonal lines.

On the rectangle, cut a window on the right to show the color bands and numbers and cut a small area on the center bottom so you can turn the smallest circle. If everything lines up and moves ok, staple the rectangle to the edges of the square and bend the ends of the brad fastener flat.

Write these variable names in pencil above the window and indicate with arrows: "First Color Band","First #", "Second Color Band", "Second #", "Multiplier", "Third Color Band". Once happy with the spacing, trace over with pen and erase pencil marks.

Label your new paper tool with your name and "Resistor Color Wheel". Decorate it how you like and write down useful information, such as:

K = x 1,000

M = x 1,000,000

Fourth band gold = 5% tolerance

Fourth band silver = 10% tolerance

No fourth band = 20% tolerance

V = I x R

I = V / R

R = V / I

Step 5: Use Your Resistor Color Wheel

Solving for the resistor value

Oh no! You've found a random resistor, and you don't know it's value. The same thing happens to me all the time. Here's how to figure out the resistance value.

  • Turn the disks on your your Resistor Color Wheel so the same colors of the random resistor show in your viewing window.
  • Write down the corresponding numbers and multiplier. Then do the math.

Let's test with my random resistor, which has these color bands: brown, green, orange, and gold. When I turn the disks, I get 1 for the first number, 5 for the second number, and x1K for the multiplier. My random resistor is 15K ohms. The gold band means the exact resistance could be + or - 5% of 15,000 ohms. Since 5% of 15,000 is 750, my resistor will fall between 14,250 and 15,750 ohms.

When Jack and I test the resistor with a multimeter, we got 14.94 K ohms, which is well within the 5% tolerance.

Solving for the color bands

A more likely scenario is that a circuit calls for a specific resistor value, such as 1K ohm, and you don't know the corresponding color bands. Turn the disks on your Resistor Color Wheel to match the numbers. In the case of a 1K resistor, the first number is 1 and the second number is 0. Now the multiplier is whatever number you need to multiply 10 by to get 1K or 1,000.

10 x (multiplier ) = 1,000

multiplier = 1,000 / 10

multiplier = 100

Turn the large disk until you see x 100. The three color bands showing in the viewing window are brown, black and red.

Comments

author
Nuonaton (author)2017-03-21

This is great! Making one to go in my project!

author
leseagle made it! (author)2017-02-04

I updated the back with your credits and added some other information...

Hope you like it.

Ohm Wheel.pdf
author
JackANDJude (author)leseagle2017-02-19

Les, I printed and assembled your pdf. It all lines up perfectly. :) Thanks again!

resistor color wheel les.jpeg
author
leseagle (author)leseagle2017-02-05

Thanks, but it is Les...

If you want to send me the the other basic plan, I can make one of these up for you as well.

Les@LesLaMotte.com

author
JackANDJude (author)leseagle2017-02-05

WOW! Thanks Lee! That looks so cool. :) I really appreciate you sharing your graphic design skills this way.

The reasons I made this... 1) Looking up resistors on random online charts is a hassle. I wanted a low tech, portable method that I could use in my kitchen or with kids during workshops. 2) Drafting and coloring this by hand is an engaging way to brush up on geometry, following instructions, and introduce resistors. For me it was an exercise in writing directions others could follow. 4) I like making color wheels for various purposes. ;) Here's a paint mixing color wheel Jack and I made last summer:

https://www.instagram.com/p/BI3dbNnAEb0

color wheel paint.jpg
author
leseagle made it! (author)2017-02-04

Great idea you two... I decided to make one and so I will share with you my graphic design skills with a finished printable PDF and then laminate. Hope you enjoy it as well as your first attempt... thanks for sharing.

I hope I did it right let me know if I messed up...

Curious as to why you make this? Are you beginning to learn how to do electronics? So what have you made? Leseagle Minneapolis, Minnesota USA

Ohm Wheel.pdf
author
KISELIN (author)2017-02-03

Actually You should start with black.... = 0 . Black isn't actually a colour at all.... black is black.. as they sing in them 60's, but there's a dilemma, Don't use the third ring as a multiplier, (black is zero multiplied with.... gives you zero), the third ring ONLY says how many zeros you put there.... after them 2 ring's,

e.g. brown, brown, brown will make: 2, 2, +1 = 220

Note! It mearly is a symbolic , (not a mathematical ), way to show it's value

author
KISELIN (author)2017-02-03

The oreder isn't right

author
KISELIN (author)2017-02-03

Gee nice job You've done. Anyway, I try to help You with thi dilemma of them colour-codes. I sort them by a system developed by/for me only. The first 3' rings, (there are resistors with 4 ring's + the tolerance ring = 5 rings), on a resistor tell you; ( don't mind the 4' th ring, which is allways marked "wider" as to be the tolarance of the resistor, 1 to 20% ),

Try this, (with 3 rings ending with a colour of):

Black will be in a class of just ohm's

Brown will be in a class of 100's ohms

Red in a class of kiloohm's

Orange in a class of 10's of kiloohms

Etc... mega... giga.. tera.. atto..

author
KISELIN (author)2017-02-03

Colour codes

author
KISELIN (author)2017-02-03

Gee you got my vote, sure. The magic behind them colour-codes lays in the spectrum for a human kind to see. We; (humans), only see a wery narrow spectrum of colours. So we have to adapt ourselves in that. So, the colour-code goes like a rainbow, from dark black through brown to red, to be a mixture of red and yellow, to transfer ower to all yellow, to go ower to a mixture of yellow and blue, that will be green, and finaly turn in blue.... after that comes röntgen, UV, Laser/red, Laser/blue.. and then comes them of humanoids developed spectums

author
KISELIN (author)2017-02-03

Just them colours

author
maggierp (author)2017-02-03

Great idea! Simple and Practical.

author
Left-field Designs (author)2017-01-31

Nice little instructable, I wished I'd thought of something like this, nearly 15 years reciting "Better Be Right Or Your Great Big Venture Goes Wrong"

author
sandilya.anisetty (author)2017-01-30

Nice idea. I liked it.

author
kode1303 (author)2017-01-29

I love it! I might use the idea in my own teaching.

About This Instructable

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Bio: Hi, I'm Jude. I make toys and electronic gadgets.
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