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I'm a developer who has always had a love of the low-level electronis, but I have always been intimidated by it since resistors all seem to be color based and as a color-blind person, this is difficult to work with.

So my question to everyone here is if they know a good, practical way, to work with resistors (mark them, shelve them, etc). This is the one thing that keeps me from doing more electronics hobby stuff since I hate spending an hour trying to find a 10K resistor in my collection of a few hundred.

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    \$\begingroup\$ This is begging for an over-engineered computer vision based solution! (not a serious suggestion) \$\endgroup\$ – Jon L Nov 15 '11 at 2:48
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    \$\begingroup\$ @JonL: Everyone's got a smartphone nowadays and they have vision reconnection software on smartphones that automatically translates text into other languages and pastes them on the screen...why not resistor bands? (serious suggestion) \$\endgroup\$ – Faken Nov 15 '11 at 4:15
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    \$\begingroup\$ I'm not colorblind, have good eyesight, and I still can't tell the difference between resistor bands sometimes. \$\endgroup\$ – endolith Nov 15 '11 at 16:27
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    \$\begingroup\$ All russian-made resistors (that I have seen) have proper text markings on them. I really wonder why the band system became so widespread; is it really any cheaper at all? I also prefer their method for coding the magnitude: 47K instead of 473, 4K7 instead of 472, etc. \$\endgroup\$ – Roman Starkov Nov 16 '11 at 19:51
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    \$\begingroup\$ @romkyns: The issue isn't just aesthetics, but also relates to things like visual inspection. If one has a board which is supposed to have eight 10K resistors next to a 4.7K resistor, someone inspecting boards can observe the color pattern at a glance, and can easily notice any board where it differs. If parts were labeled with text but all were oriented consistently (as might be the case with hand-inserted parts), inspection could still be pretty fast. Combine text labeling with random orientation, though, and inspection would be slow. \$\endgroup\$ – supercat Apr 19 '12 at 23:03

10 Answers 10

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Try not to be intimidated by the colours, I think it should be easy to get round this. Certainly I wouldn't let it put you off electronics, too much fun to be had :-)

You would ideally have them sorted into separate marked drawers anyway. For example these storage cabinets are what we use. It has 44 separate drawers that can be divided themselves into three parts with dividers, and a slot at the front for a label card. There are many types/sizes around so find something that suits your needs.

That gets you "pretty certain" that the resistor you take out of the drawer will be the right one.
To make sure though, I would maybe buy a cheap multimeter (or repurpose one) and set it up as a value tester. If you make a little frame to set the probes just the right distance apart, you can quickly place the resistor between them and double check it's value.

This is more for loose resistors, but another option is to keep them in their packets in the drawers until needed, then take out as necessary. Though you can get errors in the packaging/component it's very very rare, and if you test one you can be even more sure all the rest will be the same anyway.

This should ensure you have very little chance of making a mistake (probably about as much as anyone else, many don't go by the colour bands anyway)

Most other components nowadays have values/codes marked on them, and if you are working with SMD (most) resistors do too - it's the unmarked capacitors that are the pain (for everyone) there :-)

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    \$\begingroup\$ Thanks for the detailed answer, I really like the cabinets you linked but will need to find something similar here in the US. \$\endgroup\$ – Mike Nov 15 '11 at 15:29
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    \$\begingroup\$ Places like Farnell/Newark, RS, Digikey, Mouser,etc do stock these cabinets also (the same Raaco range) However the price is significantly higher (about double IIRC) which is why we got them from Rapid. There are plenty on eBay though, here is an example... \$\endgroup\$ – Oli Glaser Nov 15 '11 at 15:50
  • \$\begingroup\$ ...and the list it came from. The dividers on that page can be used to separate the drawers (as mentioned above) \$\endgroup\$ – Oli Glaser Nov 15 '11 at 15:51
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    \$\begingroup\$ As far as a little tester goes - there's this :) robotroom.com/Minifigure-Multimeter.html \$\endgroup\$ – rfusca Nov 15 '11 at 16:16
  • \$\begingroup\$ @rfusca - nice! I wish I had one of those... \$\endgroup\$ – Oli Glaser Nov 15 '11 at 19:06
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I use only surface mount resistors. Most 0603 and larger resistors are marked in high-contrast silkscreen with the numerical value of the resistor:

enter image description here

You may need magnification to read 0603 and 0805 markings.

The smaller ones are not marked at all. You get used to dealing with them. Just keep the different values in separate bags or bins. It is no different than leaded resistors when you can't read the color bands.

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    \$\begingroup\$ +1, I have not relied on the markings on a resistor in years, I just keep them bagged/taped by value in clearly labelled bags. Obviously not applicable if you are big on re-use and salvaging ;) \$\endgroup\$ – drxzcl Nov 15 '11 at 10:08
  • \$\begingroup\$ Also, the larger ones (0603 or 0805 (depending on tolerance) and up) are marked with text indicating the resistor value, which can be read by a colorblind person. \$\endgroup\$ – Kevin Vermeer Nov 15 '11 at 17:04
  • \$\begingroup\$ @KevinVermeer Yes, they can be read by a colorblind person with otherwise very good eyesight! :) Those numbers are SMALL! \$\endgroup\$ – user3624 Nov 15 '11 at 20:31
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    \$\begingroup\$ @David - Or by someone with a microscope or loupe. That's practically required nowadays. \$\endgroup\$ – Kevin Vermeer Nov 15 '11 at 20:34
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If you search the net for these words: color recognition blind iphone software you get more then enough to start with. Add resistor to the words list and joy is all yours.

  1. Ohm sense is an iPhone app that will take a picture of a resistor and calculate the value based on the color bands.
  2. 20 iphone apps for color blind
  3. Someone else has the same problem as you do. Another one, too.

You can also search for android instead of iphone if that is your preferred mobile platform.

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  • \$\begingroup\$ Any suggestions for android apps? I tried Google Goggles, but it didn't work. \$\endgroup\$ – MBraedley Nov 15 '11 at 14:12
  • \$\begingroup\$ No, sorry. Nothing for Android that I am aware of. \$\endgroup\$ – avra Nov 29 '11 at 9:54
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If you're working with resistors you'll likely have a multimeter on hand. It only takes a moment to check the resistance with the meter. If it's something you need to do often, it might make sense to dedicate a cheap meter and build a jig to hold the probes in some convenient position.

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  • \$\begingroup\$ This is the way I was thinking to do it, it seems to work most of the time, but again can take a while if I keep grabbing the wrong ones. \$\endgroup\$ – Mike Nov 15 '11 at 15:20
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    \$\begingroup\$ @weijiajun As others have said, sort your resistors by value -- don't just keep them jumbled in a single container. There are about a million storage options. A case of 3x5" antistatic zip bags will last a lifetime and can organize all your components in a standard format. You can even use a heat sealer to create a seam in the middle: two compartments to hold two separate resistor values in one bag. Or, there are plenty of segmented parts boxes and tackle boxes on the market. \$\endgroup\$ – Caleb Nov 15 '11 at 15:45
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Have you tried looking at resistors through different color filters? I doubt that any one filter would allow you to distinguish all ten colors, but would think it likely that you could find a pair that would work. Alternatively, it might be possible to build a "resistor reader" light which would have two or three colored LEDs that blink in different patterns. This would cause the bands on the resistor to blink in patterns that would vary with their color. Some experimentation would be required to determine the best combination of LED colors and blink patterns.

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    \$\begingroup\$ The filters did actually work much better then I would have thought. \$\endgroup\$ – Mike Apr 19 '12 at 22:33
  • \$\begingroup\$ @weijiajun: What sorts of filters did you use? \$\endgroup\$ – supercat Apr 20 '12 at 15:00
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The 1% resistors we have at work are marked with printed digits instead of stripes. The digits work the same as the colors: ABCD is (A * 100 + B * 10 + C) * (10 ^ D). I'm not sure if this is some military thing, but you should be able to see from data sheets if the 1% resistors you're looking at are marked with colors or digits.

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  • \$\begingroup\$ Every SMD that I have used that is large enough to have printing has had printing. I thought most of ours were 3 digit, but they were not precision, and the situation is still a simple ABD. \$\endgroup\$ – Kortuk Nov 15 '11 at 7:38
  • \$\begingroup\$ SMD resistors are still a lot harder to handle than leaded types. \$\endgroup\$ – Mike DeSimone Nov 15 '11 at 9:58
  • \$\begingroup\$ Yeah where I'm using a breadboard to learn thing surface mount seemed to not really fit in. however I did notice that some of them have letter or numbers, both of which are better for me. \$\endgroup\$ – Mike Nov 15 '11 at 15:23
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At a company I used to work for we used Dale/Vishay parts that had the value printed numerically on the body.

Resistors

The data sheet had a table that showed how to read the value and tolerance. (I downloaded the example data sheet from TTI, but you can buy the parts from lots of different vendors.)

Data Sheet

The parts we used were pretty pricey because we needed low tolerance, but if you shop around and buy in volume you should be able to find them at an affordable price. The vendors we bought from supplied them in boxes of 100 or reels of 1000.

One additional advantage to the numerically coded values is that they're easier to learn. We used to hire high school students to solder boards over summer breaks, and we found that they learned how to read these resistor values much more quickly than they learned the color code.

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I tend to either tape 'strips' of resistors to an index card, and cut them off as needed, or have them in a small bag taped to an index card. When starting in projects, i do the same with all the resistors and other components needed, though i often tape them to a circuit diagram - this makes it a lot easier, even if you're not colour blind.

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Friends,

1-27-2017 - As a colorblind person with this problem, I looked for but could not find 'OhmSense'; it seems to have disappeared. I DID, however, find a resistor-valuation app for the color-blind, though it has a couple of limitations.

You might check out an iOS app called 'ResistorVision' by Jera Design; you can find it at the app store. Focusing on a resistor against a pale background will allow it to read the bands and give you the values. It does not, however, work with resistors with a blue body or with resistors below 10 Ohms, though they are working on both these issues. Another limitation is that it has trouble working against dark, complex or visually-confused backgrounds, so reading the value of a resistor 'in situ' may be problematic. Seems to work well on the workbench, though, within the limits described above.

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I have linked a cheap USB microscope (20x setting) to my laptop. Gives a good fullscreen picture of resistors with colour codes. I have tried searching for a program that will output the colour of the bands as text, i.e. Red, Black etc. when placing the cursor over the band. I had one some years back but cannot find it now or anything suitable for Windows 10. Plenty that will give information as percentages of R, G and B though. Many of these apps are now for Android or IOS but even with a closeup lens the bands are not large enough to work. A real luxury would be one that actually read the bands from the screen automatically but that is perhaps just being greedy!

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