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Wed 2nd Feb 2011

I set up the studio flash to take pictures of the butterfly from the previous post. One of them made an interesting pzzzt sound and gave off a thin plume of smoke before I could pull the plug.

I took it apart to see what was going on and found the offending resistor in the space arrowed.

Urgh! Definitely the source of the pzzzt!

Resistors use coloured bands to show their value. There are usually four bands, the first two code for the first two digits of the resistors value, the third is the multiplier, basically the number of zeroes on the end of the number. The final band shows the tolerance of the resistor, how accurate it is.

I thought I'd make a code wheel to help find the value of resistors by dialing in their colour bands.

Download the file from the link and print out the parts onto thin card (230 gram / 230 micron) Cut out the holes the cut out the parts. Lift up the three tabs in the largest disk. Thread the other two disks into place as shown above.

Fold the tabs flat. Dab a small amount of glue on each tab and glue the cover into place. Make sure the disks are free to turn.

Flip the disk over and glue the guide on the back.

To use the Resistor Code Calculator, dial in the colours and read off the number - simple!

So for example a yellow, purple, orange resistor, would have a value of 47k ohms.

Paper engineering meets electronic engineering.

Other projects you might be interested in:

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Thursday 3rd Feb 2011 17:49

### maxlrainer

Thank you Rob. My son has got an electronic experimental kit as a Christmas gift. So the Colour Wheel is very useful for him (an much more plausible than the table which was included).

Thursday 3rd Feb 2011 20:31

### hugo leandro

I didn't know Rob was good at electricity and resistor, as well. It is well done, and it moves. Helpful for electronic engineering students and for mechanical automata ones. Congratulations, also!

Tuesday 15th Feb 2011 05:35

### drinkumbrella

Having now built the resistor wheel, my brain is now churning on similar wheel constructions, like seekrit message decoder wheels. Star charts. Stuff like that. The mechanism worked well, and the double-thick back makes it feel like I'm not about to bust the wheel when spinning the pieces.

Tuesday 15th Feb 2011 09:48

### robives

I know, there all sorts of things you can do. Check out the Nuclear Bomb Effects Calculator mentioned in the Make Blog post mentioning this post.

Friday 18th Feb 2011 06:24

### RashieCoat

Looks to me as if Rob is good at EVERYTHING!

Saturday 30th Jul 2011 00:43

### DobbyKnits

This is such a marvelous and useful tool that I laminated each of the pieces with 5 mil laminating film so I can keep it in my electronics kit without damaging it.  It is a wonderful item and I can't believe I ever worked without it! ★★★★★

Saturday 30th Jul 2011 09:04

### Smelter

And you are not the only one!

http://www.robives.com/blog/electronics_weekly

Thursday 19th Jan 2012 14:29

### gerald

Nice idea, I printed it at once. Too bad it doesn't take resistors with 5 bands into account.

Good work anyway.

Regards,

Gerald

Monday 23rd Apr 2012 16:42

### Dragonnize

Hello,

Thank you, it's very good.