Learning Aid - resistors

[Enzo]

I found this in Embedded Electronics Journal, and it may help you learn the resistor color codes.

Graphical Resistance Calculator

Set the colors on the resistor image and it tells you the resistance.

Very simple.

[Steve Conner]

There are dozens of mnemonics for remembering the colour code, most of them un-PC or even unprintable.

Electronic color code - Wikipedia, the free encyclopedia

The one I remember ends "... But Virgins Go Without"

[mike_mccue]

thanks for the link.

Now if I could just tell what color the bands on the resistors really are? The bands mostly all look blurry and sort of mud colored to my eyes these days.

best,
mike

[Enzo]

Yep there are lots of memory aids. I Have hired and fired technicians over the years, and at interview, one of the first things I do is check the general knowledge, "Here, read this color code." I had a guy once looked at the resistor I handed him them started reciting aloud, "Our bad boys..."

When A was a kid, I just learned them, I never had a mnemonic. I remember yellow/purple was the first pair I managed to internalize. I knew that was 47 even when I couldn;t quite remember what blue/gray was. And it didn;t take long for the others to fill in, until one day I just knew them.

But I did have - aside from the chart in a book - a little cardboard resistor calculator things that worked just like this thing I have linked to above. You turned three little cardboard wheels so the right color appeared in an opening in a picture of a resistor. Then numbers appeared in other openings. I used to look up the ones I was not sure of. Like green. What is that darn green anyway?

[Old Tele man]

The one I remember ends "... But Virgins Go Without"

...ours (USN) ended with "...Violet Gives Willingly..." and the tolerances were: "...Get Some Now..." for Gold(5%), Silver(10%), None(20%).

...not PC, but VERY rememberable, for sure!

[Robert M. Martinelli]

...ours (USN) ended with "...Violet Gives Willingly..." and the tolerances were: "...Get Some Now..." for Gold(5%), Silver(10%), None(20%).

...not PC, but VERY rememberable, for sure!

Well, according to what you and Steve said, Sigmund Freud was definitely right !!

Cheers

Bob

[dumbassbob]

Thought I would bring this up to the top again. Great for a dumbass like me

[JHow]

Started out with a wheely thing like Enzo mentioned. Then just learned the codes, which was great until I got older and now can't read them very well, so I pretty much measure them all anyway before soldering.

[jrfrond]

Yep there are lots of memory aids. I Have hired and fired technicians over the years, and at interview, one of the first things I do is check the general knowledge, "Here, read this color code." I had a guy once looked at the resistor I handed him them started reciting aloud, "Our bad boys..."

When A was a kid, I just learned them, I never had a mnemonic. I remember yellow/purple was the first pair I managed to internalize. I knew that was 47 even when I couldn;t quite remember what blue/gray was. And it didn;t take long for the others to fill in, until one day I just knew them.

But I did have - aside from the chart in a book - a little cardboard resistor calculator things that worked just like this thing I have linked to above. You turned three little cardboard wheels so the right color appeared in an opening in a picture of a resistor. Then numbers appeared in other openings. I used to look up the ones I was not sure of. Like green. What is that darn green anyway?

LOL! Same here. I didn't have a funny mnemonic to recite either, though a couple of them ARE hysterical! Back then, you just kinda learned it verbatim. And I believe I STILL have that cardboard wheel thing from Radio Shack around somewhere. You know how techs are. We NEVER throw anything away!

Here is a cool site with a lot of Javascript calculators for electronics. It's always good to have them available:

Bowden's Hobby Circuits

[Enzo]

I am a sucker for all the various little cardboard sliderule sorts of things.

[CraigW]

I still have my original RS calculator with the 3 wheels, I bet it is close to 30 years old now.

[Sock Puppet]

now can't read them very well, so I pretty much measure them all anyway before soldering.

Ha Ha - me too.

Body Tip Spot.

[Ronsonic]

One of our counter wenches decided that this being the 21st Century and all there should be a more polite mnemonic, Beautiful Begonias Rise Over Your Garden But Violets Grow Wild. Which apparently I could remember. She never did cure us of some of our job titles.

I'm somewhat color vision impaired. Which is actually a bit more trouble reassembling mixers than dealing with resistors.

Solder Monkey

[Axtman]

I wish that I could find an online resistor color quiz...especially one with a timer. I know the code pretty good but still have to resort to the color code poster on the wall.

BTW As procedure I always check the reistor with a VOM before installing it. I find many resitors that are out of tolerance.....and I have no tolerance for that! ;-) Yesterday I check a 2 watt carbon comp that should have been 220 ohms (red red brown) it tested out at 458 ohms!

[jrfrond]

I wish that I could find an online resistor color quiz...especially one with a timer. I know the code pretty good but still have to resort to the color code poster on the wall.

BTW As procedure I always check the reistor with a VOM before installing it. I find many resitors that are out of tolerance.....and I have no tolerance for that! ;-) Yesterday I check a 2 watt carbon comp that should have been 220 ohms (red red brown) it tested out at 458 ohms!

That's not out-of-tolerance, that is plain mismarked. It was probably meant for the 470 ohm bin.

As far as fluency in the color code goes, just practice it yourself. Get out a bunch of resistors and blow through them, reading them as fast as you can. Eventually, it will become a second language to you. BTW- if you haven't noticed this yet, once you get past black and brown (0-1), you are roughly into the spectral (rainbow) colors (2-3-4-5-6-7), until you get to grey and white (8-9). Don't know if this helps.

My wife recently purchased this rainbow-themed set of Tupperware bowls. I think she wonders why, when I put them away, they are stacked in "order" every single time. Then again, I line up my shoes too.

[Enzo]

What is this "shoes" you speak of? I make a technician's wage.

A lot of times you find the little inline connectors within a product - you know, 6 or 8 wires in a rowe. MAny of them have the one on the end one color, and the rest all a different color. Like the end one is black, and the rest white or gray. The odd one indicated pin 1. But some companies use the color code. so the wires across your connector would be brown-red-orange-yellow, etc. Find one of those cables in some piece of junk and tack it to the wall in front of you. Visual reminder.

One thing helped me learn was the number sequence. There are standard values of resistors. The numbers are in a series of 10, 15, 22, 33, 47, 68, 100. That is the 20% series. 20% parts were the most common when I was growing up, and you find them in old fenders. SO for example 10k, 15k, 22k, etc. There was no point in values between those since the tolerance ranges overlapped as it was.

SO when learning, there were certain combinations. Other than the 1 in 10 and 15, the colors didn;t repeat. blue and gray went together as 68. You were not going to find 64 or 58. SO yellow-purple was a common pair and orange-orange. ANd so on. To me this was easier than just learning them as individual numbers. I knew yellow-purple was 47, which made 4 and 7 individually that much easier to recall.

10% sequence added a few:
10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82, 100. The tighter tolerance ranges needed numbers between the others.

5%, well, by now, you pretty much just need to know all your numbers.
10, 11, 12, 13 ,15, 16, 18, 20, and so on.

But even in this day of 1% parts all over, we still tend to use the old common values. Yes, I do see such things as 243k plate resistors in a preamp circuit, but mostly I still see 220k or 100k. SO even using 5% parts, most designs still reach for the 1.5k cathode resistor rather than the equally valid 1.3k or 1.6k. SO most parts you see will still have the common color pairs.


I gotta say, it MAY not be a deal breaker, but when I hire a tech, count on the first test question I ask being some color codes. This color code bit of knowledge is so basic, universal, and all over, that I expect a man to know it. If you are plpanning to get yourself hired in electronics, do yourself a favor and take the time and make the effort to make it second nature. I tend to think when assessing an individual, that if he doesn;t know the colors, chances are his experience is limited.

[jrfrond]

What is this "shoes" you speak of? I make a technician's wage.

Well, ONE pair of shoes anyway! The others are sneakers, which for me, are EVERYDAY shoes!

I gotta say, it MAY not be a deal breaker, but when I hire a tech, count on the first test question I ask being some color codes. This color code bit of knowledge is so basic, universal, and all over, that I expect a man to know it. If you are plpanning to get yourself hired in electronics, do yourself a favor and take the time and make the effort to make it second nature. I tend to think when assessing an individual, that if he doesn;t know the colors, chances are his experience is limited.

And after that, ask him/her to read a numerically-coded capacitor. You'll have them talking to themselves!

[dumbassbob]

This has been a big help

[madkatb]

A friend of mine just bought a pedal kit and found he was missing a 150K resistor. He described it to me as brown, green, black, orange. Threw me for a loop. I guess everything I see on my bench is "old school".

[zero cool]

I skipped over so many simple things that to this day I don't have the resistor codes memorized. I still use my radio shack 3 wheeled resistor decoder ring! But i find it funny that for some reason the Yellow Purple 47 is the easiest one to remember? The colors are starting to sink in now that my hobby has become my full time job as I have been laid off again. and as i go along i find that the colors are just sort of getting memorized as i go.

I like that Link you posted Enzo, that's a nice calculator. I wish it could be downloaded.

Zc

[dumbassbob]

That why I keep bringing it back to the top of forum I can't download it.I forgot where it was,D-assBob

[trevorus]

This has been my go to guide for code calculators. http://www.electronics2000.co.uk/ It's installed on my laptop and my desktop, and I take the laptop to the work bench. Tube Data Sheet Locator is great for looking up specs, tube sheets, etc.

[m-fine]

I know what colors correspond to what numbers, but the thing I am missing is the color conversion chart for 40-60 year old resistors where what may have been violet or brown in decades past now are different shades of grey. Either the colors fade, or every resistor in my wah pedal is 880 Mohms!

[trevorus]

I know what colors correspond to what numbers, but the thing I am missing is the color conversion chart for 40-60 year old resistors where what may have been violet or brown in decades past now are different shades of grey. Either the colors fade, or every resistor in my wah pedal is 880 Mohms!

Then it's time to hit them with a multi-meter. And that's fun when there are 900 resistors... Blech!

[jrfrond]

A friend of mine just bought a pedal kit and found he was missing a 150K resistor. He described it to me as brown, green, black, orange. Threw me for a loop. I guess everything I see on my bench is "old school".

It's a precision metal film resistor, which usually employ a five-band code. In that case it's:

- First digit, second digit, third digit, number of zeros, tolerance (the 5th band should be there). For example, while you COULD express 150K with a traditional four-band code, you couldn't express 155K. Anything requiring more precision usually has silk-screened numbers.

[rockin roy]

I just remember what a rainbow looks like, that is where this all comes from. I also recomend useing an ohm meter (always). Parts can be bad straight from the manufacturer.

[defaced]

^Same here. Black - Brown - ROYGBV - Gray - White. And after a while, you just kinda get used to seeing the same values and you start to remember what is what. The only thing that kills me are multipliers on 5 band resistors. Those I still haven't internalized.

[Enzo]

Don't think of them as multipliers - regardless of the number of bands. Instead of multipliers, think of it as "number of zeros." So, red-red-yellow-orange would be 2243 or 224 000 = 224k. A plain old 220k was red red yellow in three band = 2-2-4 = 22-0000. In four band it becomes red red black orange, or 2-2-0-000. Same thing.

Example: orange means 3, or it means x1000. But x1000 is the same thing as adding three zeros to a number.