Can you tell the value of a resistor from the color bands? - Page 1
Forum section: electronics / beginners

author: Seekonk
author_rank: Super Contributor
timestamp: February 22, 2018, 03:52:30 pm
content: I can't. No, it is not what you think. I've been in electronics over 50 years. Started by cuttingresistors out of old TV's. Had a drawer with a couple thousand and I could not only quickly findthe value I wanted at a glance, but one that was pretty close. Now I can't figure them out with amagnifying glass. I have to use a meter. Brown, red and orange are about the same. Even when nextto each other it is hard to tell the difference. Same with green and black sometimes along withviolet and grey. A variety of background colors doesn't help with minimized ink. I have to get outa meter to be sure and some times I am pretty shocked at what the value is. Am I just getting tooold? Basic colors ought to have a standard.

author: Paul Rose
author_rank: Regular Contributor
timestamp: February 22, 2018, 03:59:32 pm
content: It has gotten harder as my eyes have gotten older ( I'm 47 ).I've found that a bright light helps quite a bit. A nice full spectrum incandescent light is best. I have a lot of trouble distinguishing color bands using an LED flashlight, for example.

author: grumpydoc
author_rank: Super Contributor
timestamp: February 22, 2018, 04:37:07 pm
content: +1For some reason it has got much harder.As you observe all the colours are muddy, indistinguishable and just "meh"; the band spacing is usually totally even as well meaning you can't tell which end to start.Buff coloured bodies seem easier than blue (which seems to predominate today).

author: rstofer
author_rank: Super Contributor
timestamp: February 22, 2018, 05:08:49 pm
content: I have always had defective red-green color vision. In the '50s, I could read the color bands quite well. Why? Well, the Heathkits I was building tended toward 1/2W resistors and larger. Today, 1/8 watt is more common and they are much smaller. 1W resistors are EASY!I gave up on color bands for anything other than sorting on the 3rd band many years ago. I use a meter for every application.

author: ataradov
author_rank: Super Contributor
timestamp: February 22, 2018, 05:53:54 pm
content: I grew up with resistors that had their value printed on them. I think this system is way more superior. Color bands may be easier for machines, but as a human, I'd rather rotate the resistor around a bit, and read an actual number.And I don't bother learning even basics of color codes. Just store resistors in marked bags, and use multimeter when not sure.

author: Muttley Snickers
author_rank: Unknown
timestamp: February 22, 2018, 06:35:02 pm
content: I did an amateur radio course back when I was 16 and the first thing we learnt was the saying below along with the phonetic alphabet, the teacher added a bit on the end for the tolerances but I could never remember what it was, anyway I never forgot the rest and I'm sure that there would be variations on the theme.0. Black/ Big1. Brown/ Boys2. Red/ Race3. Orange/ Only4. Yellow/ Young5. Green/ Girls6. Blue/ But7. Violet/ Violet8. Grey/ Generally9. White/ Wins

author: lordvader88
author_rank: Frequent Contributor
timestamp: February 22, 2018, 06:54:21 pm
content: For years I couldn't remember the order, and didn't notice its just the spectrum of colors , starting at contrast black=0 and ending with white=9. So now its easy.Yeah the 4 band blue resistors are tricky under bad lights. And why not use a pattern or something for the tolerance band.

author: rrinker
author_rank: Super Contributor
timestamp: February 22, 2018, 07:16:22 pm
content: The one I learned it similar to Muttley's but, ahem, not suitable to a family forum.I have the same problem as the OP. In part I might say it's because I've gotten older and my eyesight has gotten worse - actually only about half there in my right eye. But I do have some old stock resistors from the 80's and I have no problem seeing the color bands on those. The new ones though, especially tighter tolerance ones with 4 bands, it's very difficult. The colors are washed out compared to the fairly distinct colors used years ago. It's to the point where I don;t even bother, I just always have a meter set on ohms and check each one. Size doesn't help, 1/2 and 1/4 watt resistors are huge compared to 1/8.

author: grumpydoc
author_rank: Super Contributor
timestamp: February 22, 2018, 07:43:05 pm
content: Quote from: rrinker on February 22, 2018, 07:16:22 pmThere was a stink a couple of years ago in the UK when a teacher taught a very non PC mnemonic for the colour code - something about people of race and questionable parentage.Pretty certain he got sacked for it.I learnt Black Beetles Running On Your Garden Bring Very Good WeatherYes, I learnt the other one above as well but itisn'tsuitable for today's world.

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: February 22, 2018, 07:51:35 pm
content: Colour codes were really useful when they were the standard two digits and multiplier, plus tolerance. Unfortunately, few metal film types adhere to this any more. Thus the first problem you have is the identify the scheme they are using. Then you have to identify which end to read from. This is often impossible due to red or brown being both a tolerance and a value. It's become such a mess that it's easier to whip the meter out.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 22, 2018, 08:00:57 pm
content: I wonder if a factor might be poorer CRI (colour rendering index) of LED lighting ?Not much red, so this may make it harder to distinguish resistor colours

author: AndyC_772
author_rank: Super Contributor
timestamp: February 22, 2018, 08:25:25 pm
content: I can't possibly post the aide-memoire that I was taught to help remember the colour code sequence.#1 was 'bastards'.'Thank' this post if you also grew up before political correctness, and think you may know the same sequence.

author: grumpydoc
author_rank: Super Contributor
timestamp: February 22, 2018, 08:28:19 pm
content: Quote from: AndyC_772 on February 22, 2018, 08:25:25 pmThat sounds like one I mentioned above.......It's the one which goes0 = ***1 = bastards2 = ***3 = ***4 = ***5 = ***6 = but7 = ***8 = ***9 = without.I think that's as close as I can get without being banned.

author: grumpydoc
author_rank: Super Contributor
timestamp: February 22, 2018, 08:29:48 pm
content: Quote from: mikeselectricstuff on February 22, 2018, 08:00:57 pmThat thought crossed my mind as well.

author: Dubbie
author_rank: Unknown
timestamp: February 22, 2018, 08:55:10 pm
content: Quote from: AndyC_772 on February 22, 2018, 08:25:25 pmI think you meant to say, "Thank this post if you grew up when I and everyone I knew was racist as fuck"

author: hamster_nz
author_rank: Super Contributor
timestamp: February 22, 2018, 10:05:07 pm
content: Quote from: grumpydoc on February 22, 2018, 08:29:48 pmI use a LED desk lamp magnifier lamp and am convinced that it is a size / age of eyes thing. With a little magnification identification is easy. Sorting loose parts into different containers for decades helps heaps.Anyhow, I only ready need to know black = 0, brown = 1, red = 2, orange = 3. yellow = 4. That is enough to get pretty much any value I use - eg 330 for LED current limiters, 10k and 100k pullups.

author: drussell
author_rank: Super Contributor
timestamp: February 22, 2018, 10:28:15 pm
content: I still have no problem with resistors (and I still use mostly incandescent lighting) but yes, I do really notice the lack of spectrum width in anything except bright incandescent or sunlight in today's lighting. (Not that standard old-school 40-watt florescent are very good either, and that's way older than me... but I've always known about CRI because of them, even way back when I was a kid...)You can see it in many places, you don't need to be looking at a Pantone chart or dfull spectrum, even seemingly simple craft-work threads, yarn, etc. Just try looking at a DMC thread color chart under most of today's trendy lighting!...

author: Wimberleytech
author_rank: Super Contributor
timestamp: February 22, 2018, 10:51:49 pm
content: Quote from: grumpydoc on February 22, 2018, 07:43:05 pmBetter Be Right Or Your Great Big Voltage Goes West.

author: Richard Crowley
author_rank: Super Contributor
timestamp: February 22, 2018, 10:57:19 pm
content: I wish I still had some of those resistors from when I was a kid. Nice brown molded bodies with crisp bright color bands. Easy to read the codes back then.These days, we have murky or weird body colors on dipped (or conformally coated) "dumbell-shape" bodies.And horrible band colors that are nearly impossible to read anymore.I increasingly rely on using my little $10 "Transistor Diode Triode Capacitance LCR Meter" to confirm component values.

author: tautech
author_rank: Super Contributor
timestamp: February 22, 2018, 11:01:33 pm
content: Quote from: Richard Crowley on February 22, 2018, 10:57:19 pmYeah, that's what I first learn on too.Dad's 'little' ones were 1" long and 1/4" dia.

author: Brumby
author_rank: Unknown
timestamp: February 22, 2018, 11:45:25 pm
content: I learned the colour codes from a chart on my own - black, brown, rainbow(most of), grey, white - courtesy of my Philips EE20 kit.After a while, I could 'see' a 47K, quarter watt, 4 band carbon film resistor from its colour codes even if it was far enough away that I had to lean over to reach it. In fact, everything from 10ohms to 1M in the E12 range didn't require any thought at all.The eyes aren't quite as acute these days and the range tops out at about 2 ft ... for quarter watt carbon film - BUT the blue bodied metal film are quite something else. For starters, the darker blue body really kills the contrast which just makes things harder. Then we have the smaller size of resistor and the bands which, coupled with aging eyesight (though I don't need glasses) makes unassisted viewing more difficult.I've always had good lighting, so these problems are overcome by using my headband magnifier - but one still remains a challenge: Which direction to read. With 1% and 2% tolerance bands and values outside E12, I find myself reaching for the meter more often these days. With some of the stock I have, the tolerance band is spaced out a bit more - but it's just not consistent and/or obvious.I used to be able to pick out a value from a fistful of resistors dumped on the bench - but with the smaller blue bodied beasts, those days are gone.

author: Dubbie
author_rank: Unknown
timestamp: February 22, 2018, 11:58:37 pm
content: I find I just keep my LCR meter next to me and jam them in to quickly tell me the value, even if I bother to try and read the value, I never quite trust myself and end up measuring anyway.

author: sibeen
author_rank: Frequent Contributor
timestamp: February 23, 2018, 12:01:42 am
content: rushes inI hope I'm not late to this meeting of the grumpy old bastards clubI actually had to look at a colour code just a few days ago. Looked at it under a light, then got out the newer glasses with higher magnification, then put it under a magnifying glass and then got out the multimeter.Mine started "Bad boys..."

author: ArdWar
author_rank: Frequent Contributor
timestamp: February 23, 2018, 12:42:41 am
content: It's always brown-red or red-orange that gives me the most problem, much more if it's old fading part. Some use better, easily discernible paint than others. Some use certain shade of base paint that exacerbate things.My other problem is with 1% resistors. I always not sure if it's read one way or the other way around.

author: ikrase
author_rank: Regular Contributor
timestamp: February 23, 2018, 02:04:49 am
content: I find it remarkably difficult to tell which end of a resistor is the most significant digit and I'm pretty young.

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: February 23, 2018, 09:28:49 am
content: Quote from: grumpydoc on February 22, 2018, 08:28:19 pmOh come on, we want to know!

author: grumpydoc
author_rank: Super Contributor
timestamp: February 23, 2018, 09:40:36 am
content: Quote from: GeorgeOfTheJungle on February 23, 2018, 09:28:49 amGoogle is your friend (Wikipedia is your friend as well).

author: AndyC_772
author_rank: Super Contributor
timestamp: February 23, 2018, 09:47:15 am
content: I'm surprised it's posted anywhere; it already had shock value even when I heard it in the early '90s.

author: grumpydoc
author_rank: Super Contributor
timestamp: February 23, 2018, 09:51:00 am
content: Quote from: AndyC_772 on February 23, 2018, 09:47:15 amNo, it's there in all its "glory" on the Wikipedia page.Of course the fact that it has some shock value probably helps one remember it - many offensive or ribald mnemonics exist for this reason - oh and the fac that it's usually college students who come up with them

author: ikrase
author_rank: Regular Contributor
timestamp: February 23, 2018, 10:05:56 am
content: On a related note, does anybody notice that integrated circuit labels have gotten *impossible* to read in the last 10-15 years? Even for large DIP/PLCC/TQFP/BGA parts where there is plenty of room to print the label in large size?In the old days, it was common for the part number to be printed in highly visible white paint (esp. on some LM-numbered linear ICs). Today, it seems like you need both a microscope and very careful application of high intensity raking light to see the vague printing against a shimmering plastic background.

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: February 23, 2018, 10:11:22 am
content: Quote from: grumpydoc on February 23, 2018, 09:40:36 amFound it:https://en.wikipedia.org/wiki/List_of_electronic_color_code_mnemonics#Offensivelol. Thanks!

author: Seekonk
author_rank: Super Contributor
timestamp: February 23, 2018, 12:24:50 pm
content: Quote from: ikrase on February 23, 2018, 10:05:56 amA USB scope is always at hand these days for laser etch plastic. I swear they are now even turning down the laser to save electricity.

author: LeoTech
author_rank: Regular Contributor
timestamp: February 23, 2018, 12:45:20 pm
content: Well, I might as well ad my two cents............I am most likely the youngest person in this thread and I have most likely the best eyevision - no offense. But to be honest, i have a very hard time reading the color codes as well.When I started with electronics I tried to memorize the color codes and to read instead of measure the resistance, but I quickly gave up on that, as it proved to be fatale more than once.Even with good sight, only slightly color blind, I still can't read the color bands on metal film resistors (blue background) with 100% accuracy, so I do not trust myself when it comes to those. But when it comes to carbon resistors (light colored background) I have an accuracy of almost 100%.As most of my resistors are metal film ones I use my DMM when in doubt, but most of the time I just reach into the bag/rack for the given value and pick one.Leo

author: Howardlong
author_rank: Super Contributor
timestamp: February 23, 2018, 12:55:52 pm
content: Quote from: ArdWar on February 23, 2018, 12:42:41 amBoth of these, although mine is more to do with brown-orange.Keep in mind for us oldies that parts are smaller nowadays and five band codes are way more common, that might have an affect on ease of recognition.For example, I keep a selection of a couple of hundred resistors in the E3 series ready for solderless breadboarding from 1 ohm to 10M ohm in a transparent ziplock bag, some are four band and some five band. Some are 1/4W and some are 1/8W size. The four band I have no problem at all recognising just by glance, it’s the five banders, in both sizes, that I seem to have a slight recognition dyslexia with, I have to think a bit unlike the four banders.The only thing I struggle with memory-wise is the gold and silver multiplier, I mix thise up, that’s the only time I find myself resorting to a meter.I learned the rainbow based way when I was a kid, figuring that out by myself. Just like riding a bicycle, I found that you don’t forget. The resistor colour codes were also often used in ribbon cables back in the 80s but I haven’t seem this as much recently. On wiring jobs in the microprocessor era I tended to follow bus signal numbers with the resistor colour code when wiring up stuff off the board.The EIA96 SMD resistor codes on 0603 and larger that don’t follow the rainbow code I have little clue about and have to refer to the datasheets on the odd occasion I need to figure out a value: often a meter is faster in that instance especially out of circuit.

author: Brumby
author_rank: Unknown
timestamp: February 23, 2018, 01:25:27 pm
content: As a slightly off-topic tangent, I once worked at a company that went through a major "Filing System" change. As well as new racking and folders, there were file trolleys, project boxes and ..... colour coded stickers.The colours for the alphabetic ones didn't seem logical - but they didn't bother me too much. It was the numeric ones that had me crying on the inside. A perfectly good numeric colour coding system that had been in widespread use for several decades,completely ignored.This is a sample of what was used:ARRRRGHHH!!!!

author: tooki
author_rank: Super Contributor
timestamp: February 23, 2018, 03:25:17 pm
content: Quote from: mikeselectricstuff on February 22, 2018, 08:00:57 pmI suspect it's the combination of LED and CFL lighting with poor CRI; poorer quality paints for the color bands; those darned blue resistor bodies providing a poor background for said cheap paints; and the bands getting smaller thanks to smaller components and higher tolerances requiring extra bands.

author: dmills
author_rank: Super Contributor
timestamp: February 23, 2018, 04:29:27 pm
content: Quote from: sibeen on February 23, 2018, 12:01:42 amThat **was** the PC version!The real question is "Gives Willingly" or "Goes Without"...But yea, it is harder then it once was, and not just colour codes, the modern chip makings are more or less illegible a lot of the time, which is fine for the SMT shooter, rather less so for building prototypes. Silkscreen beats laser marking for readability on chip packages.Regards, Dan.