Rant: why resistor colors are so difficult to read - Page 1
Forum section: electronics / general

author: zapta
author_rank: Super Contributor
timestamp: November 02, 2013, 06:48:59 pm
content: Reading resistor values by color used to be a simple thing to do. A beige background and bright stripe colors provided very good color identification.I recently tried to order a resistor assortment kit and all I found was new style dark resistors with hard to read colors like this onehttp://amzn.com/B007L3I1ZAIts even more stranger with this kit where the color table has the easy to read beige style colors but the actual resistors are darkhttp://digistump.com/products/76What is the reason for this change?

author: mcinque
author_rank: Unknown
timestamp: November 02, 2013, 06:53:13 pm
content: Those are metal 1% film resistors, afaik those kind of discrete component uses that color to better identify the type. Beige background is only for carbon 5/10% resistors. Am I wrong?

author: David_AVD
author_rank: Super Contributor
timestamp: November 02, 2013, 09:15:34 pm
content: Quote from: wilfred on November 02, 2013, 09:03:15 pmI don't have any problem decoding the values on the darker backgrounds, but I do find myself looking over the top of my glasses for close up stuff these days!

author: rexxar
author_rank: Frequent Contributor
timestamp: November 02, 2013, 10:00:39 pm
content: I hate it when companies use inks where the blue looks almost exactly like green. I have a batch from Radio Shack, and I can't tell them apart at all, I have to check with a multimeter.

author: westfw
author_rank: Super Contributor
timestamp: November 02, 2013, 10:08:37 pm
content: A more interesting question is "WHY are TH resistors still marked this way, given that the technology has advanced to the point where they can put legible printing on much smaller SMT packages, most companies don't even bother marking SMT caps, and it's got to be the case that dealing with 12 colors of ink is more difficult and expensive than printing single color text?"

author: rexxar
author_rank: Frequent Contributor
timestamp: November 02, 2013, 10:15:27 pm
content: Quote from: westfw on November 02, 2013, 10:08:37 pmI've got some .01% resistors here that actually have the value printed on them. I think the main reason for not going this route is that manufacturers already have the equipment to paint bands on the resistors, it would be massively expensive to change all that machinery out. I don't think anyone would really want to do it just because the convention is old and a bit annoying.

author: grumpydoc
author_rank: Super Contributor
timestamp: November 02, 2013, 10:16:13 pm
content: QuoteYeah, but they dealt with that one by making brown, red and orange the same colour and I think they probably did the same for grey, white and yellow as well!

author: zapta
author_rank: Super Contributor
timestamp: November 02, 2013, 10:35:22 pm
content: Quote from: wilfred on November 02, 2013, 09:03:15 pmWhat about beige resistors, is it just as hard to read them?Looks like that with the dark resistors, they don't really expect anybody to reliably read them, but when it is in a circuit, a DMM does not help much.

author: steve30
author_rank: Frequent Contributor
timestamp: November 02, 2013, 10:48:03 pm
content: I usually find that the blue resistors are 1% types.I don't have any trouble reading them (provided the light is OK), but I do find the beige ones easiest to read.

author: Alex
author_rank: Regular Contributor
timestamp: November 02, 2013, 10:59:49 pm
content: Quote from: westfw on November 02, 2013, 10:08:37 pmI'm sure the answer lies within the manufacturing process. My feeling is it has something to do with the axial symmetry of these components, but also reusing older equipment as stated. Anyone know how the bands are applied?The benefit of having rings is that you don't have to worry about orientation. Imagine having to align the text upwards during population...Quote from: grumpydoc on November 02, 2013, 10:16:13 pmIt's funny cause it's true.With 1% resistors and their darker background being the standard throw-around value now, it is better to just stick with a multimeter. That is less error prone.For the guys in my signature ? we did away with the colour column (e.g. 'black-brown-orange-black') in the parts list and instead suggest to use a multimeter. Testing populated resistors is problematic, but knowing what the first two digits offers a quick check. Having said that, one customer used a 47k in place of a 470k, so that is not bullet-proof either.

author: con-f-use
author_rank: Unknown
timestamp: November 03, 2013, 09:32:27 am
content: Quote from: westfw on November 02, 2013, 10:08:37 pmThis, a thousand times this!

author: G7PSK
author_rank: Super Contributor
timestamp: November 03, 2013, 11:00:06 am
content: I have noticed that the colour is not as deep as it used to be and the base colour bleeds through in many instances so the resistor has bands of various shades of shit, Bad maintenance in the factory in order to cut costs I guess. Oh for the days when the body was one colour with separate colour on one end and a dot in the middle and all burnt the same brown once used.

author: chibiace
author_rank: Regular Contributor
timestamp: November 03, 2013, 11:56:42 am
content: i also just use the multimeter. at least one band on every resistor i seem to have trouble telling which colour it is. though i can tell patterns apart for the few values i use often.

author: apelly
author_rank: Unknown
timestamp: November 03, 2013, 12:15:22 pm
content: Fuck! I thought it was just me!I can't even tell half of them end-for-end these days

author: grumpydoc
author_rank: Super Contributor
timestamp: November 03, 2013, 12:19:57 pm
content: Quote+1

author: SeanB
author_rank: Super Contributor
timestamp: November 03, 2013, 01:44:02 pm
content: Did sort some resistors yesterday. Did it the easy way and used a LCR meter to sample a resistor inside each package and then wrote the value on the plastic bag they were in. As well sorted out a few capacitors and a few inductors. Also demo'd to other hams how useful it can be, showing the changing values of a random trimmer as you turn the shaft, along with the odd variable resistor. Had one ask if i was going to donate it to the club, gave him Frankie's eBay store name, so we will see if there are some LCR meters moving from this. Not too likely as hams are pretty tight with money........

author: GEuser
author_rank: Frequent Contributor
timestamp: November 03, 2013, 02:56:38 pm
content: Who's noticed on a populated board when using a LED flashlight or whatever that Red is brown , brown is brown and violet is brown , in other words nearly all brown!I'm gunna rant too on that subject of colors and leds so thereI use a fairly good pocket LED torch(flashlight) , it throws out to 200m , the LED has good binning but its certainly not a natural light for sure , anyway , 100m away all by itself in the open is a bit ofrustyvertical 6ft length of railway line embedded in the ground/grass thatwasused for a anchor support for a power pole ,,,,If I scan over in that direction with the area lit up real well with the LED at night that 6ft bit of steel just disappears from vision even though I know its there , someone else who would not know it was thereactuallywould not see it/know it was there!So those LED's on the front of cars/4wd's(spotlights?) would be in big trouble if there was a 6ft vertical bit of railway line embedded in the road right at the drivers position sitting on 100kph aye!Rant'o over

author: M0BSW
author_rank: Frequent Contributor
timestamp: November 03, 2013, 03:22:13 pm
content: And if you buy cheap ones, the colours don't matter as they don't relate to the actual value at all.

author: SeanB
author_rank: Super Contributor
timestamp: November 03, 2013, 05:04:10 pm
content: LED's are not going to be both high efficiency and a good light source. High efficiency means a peak in the green spectrum where the eye is most sensitive, a little blue to blend with to make white and a touch of red to balance. You need a blend that emits in a lot more of the colour spectrum, and which emits a lot more red light as well, and this drops efficiency down a lot.Warm white is dimmer for an identical cool white product, but gives a much better colour rendition. Guess which one wins in production from a cheaper to make phosphor blend and a higher apparent light output......... RGB led units can make a white light as well, but you need 2 different colours of each of the primary colours RGB to get a decent spectral spread so that materials look the same under them as they look under a continuous spectrum source like daylight or incandescent/halogen light.This shows up the best by taking a whle batch of paint sample chips and looking at them under the LED, where you will find a lot of the colours are the same, but are discernible easily in daylight.

author: zapta
author_rank: Super Contributor
timestamp: November 04, 2013, 01:22:29 am
content: Quote from: mcinque on November 02, 2013, 06:53:13 pmIt's the 1 percenters' fault ;-)

author: olsenn
author_rank: Frequent Contributor
timestamp: November 04, 2013, 01:28:44 am
content: I haven't looked at a color code since I was in university! I use either a multimeter or my LCR meter to determine the precise resistance. However, since I organize my resistors by value, I typically just grab one from a pre-labelled bin and trust it is accurate

author: free_electron
author_rank: Super Contributor
timestamp: November 04, 2013, 02:21:31 am
content: switch to surface mount. easy to read numbersi'm colorblind. i don;t see green so resistors have always been a bit of a problem. Luckily Georg Ohm invented the Ohm Meter ..

author: GEuser
author_rank: Frequent Contributor
timestamp: November 04, 2013, 07:25:06 am
content: Quote from: SeanB on November 03, 2013, 05:04:10 pmHey that's funny that's what I said!back to the topic>>>>>>>>>>

author: ivaylo
author_rank: Frequent Contributor
timestamp: November 04, 2013, 08:20:00 am
content: Certainly not a technology limitation. Eastern Europe, 30 years ago I don't remember color bands, it was all printed digits down to 1/8W.

author: hedgewallace
author_rank: Contributor
timestamp: November 04, 2013, 08:26:56 am
content: Yes, i agree with you. Sometimes the red, orange and sometimes yellow seems to look identical, when printed on cheap resistors.And then there is the challenge of figuring out which way to read it. I have read them backwards a few times, and seen the magic smoke release of of them!I think there needs to be a clearer way to read them. Perhaps a small arrow or mark to indicate which is first?Or perhaps they should just use numbers like SMD, or larger resistors.

author: DavidDLC
author_rank: Frequent Contributor
timestamp: November 04, 2013, 08:33:45 am
content: Quote from: wilfred on November 02, 2013, 09:03:15 pmExactly the same here now at 45, I use a multimeter or use the microscopeDavid

author: Neilm
author_rank: Super Contributor
timestamp: November 04, 2013, 03:07:04 pm
content: Quote from: free_electron on November 04, 2013, 02:21:31 amOnly on the larger packages. Anything smaller than 0603 isn't labelled. Not only that, one of the big manufacturers announced recently that they were going to discontinue printing the value on all their SMD resistors regardless of the package size.

author: AndersAnd
author_rank: Frequent Contributor
timestamp: November 12, 2013, 11:05:31 pm
content: Quote from: mcinque on November 02, 2013, 06:53:13 pmYou are right, beige resistors are 5% carbon resistors. Metal film resistors tend to use blue or green backgrounds.But it's not just beige background that make 5% resistors easier to read. There's only 4 stripes instead of 5 and each stipe is usually wider because of this. Which makes it much easier to read 5% resistors. Besides the fact you only need to decode 3 color stripes instead of 4 which makes it simpler and quicker. After working with 5% resitors for a while you learn to recognise the most common values without even thinking about each individual stipe and what the multiplier is.With 1% resistors I've never really recognised values without decoding the stripes individually and there a lot more different values.But I've never really worked much with 1% leaded resistors. When most components were leaded, most resistors were still 5%. A lot more resistors tend to be 1% now, often without an actual need for 1%, but most of it is SMD now.

author: AndersAnd
author_rank: Frequent Contributor
timestamp: November 12, 2013, 11:13:14 pm
content: Quote from: Neilm on November 04, 2013, 03:07:04 pmOh no, what manufacturer is that?I always hate there's no print on SMD capacitors when repairing or reverse engineering a PCB. But isn't that because the print itself affects the capacity of tiny ceramic capacitors? OR maybe it's because the print won't stick to the ceramic material. It's often very hard to get anything to stick to smooth ceramic surfaces. They even use anti stick surfaces on many frying pans now as replacement for the very toxic Teflon, which melts if the pan gets too hot.

author: GreyWoolfe
author_rank: Unknown
timestamp: November 14, 2013, 03:18:51 am
content: My bench mounted 5 diopter lighted magnifying glass helps me read the resistors including 1/4 watt. Only rarely have I had to use a multimeter to read the colour (a nod to our friends on the other side of the pond) codes.Tom, NW0LF

author: olsenn
author_rank: Frequent Contributor
timestamp: November 14, 2013, 03:20:50 am
content: I never read the colors. I pick them from a labelled bin when designing, and I read them with a DMM when repairing

author: David_AVD
author_rank: Super Contributor
timestamp: November 14, 2013, 05:29:03 am
content: Quote from: olsenn on November 14, 2013, 03:20:50 amThat's fine until the wrong part is in the labelled bin.

author: grumpydoc
author_rank: Super Contributor
timestamp: November 14, 2013, 08:20:02 am
content: On thing I find always gets me the change in "multiplier" as you go from three band to four band because when I started any interest in electronics everything was pretty much three band (which is good to E24, after all) - consequently my brain is too hardwired to look for eg a red multiplier band when searching for a resistor in the range 1-9.9k or an orange in the range 10-99kIt would have been better to have designed the colour code so as to be<first-band> "point" <second-band> [<third-band>] x 10<multiplier-band>rather than have the "multiplier" specify the number of zeros to add to the end. That way a 1-9.9k resistor would always have an orange multiplier, no matter how many bands were used for the value.Too late to change now though

author: TMM
author_rank: Frequent Contributor
timestamp: November 14, 2013, 10:41:51 am
content: Red looks like brown on a lot of metal film resistors because the bands are applied thin and translucent.Quote from: M0BSW on November 03, 2013, 03:22:13 pmYou have to be buying really nasty resistors for them not to meet spec. Even the cheapo multicomp 1% metal films (which are barely more expensive than wun-hung-low's from ebay) are mostly within 0.1%.Worst i've seen were some '1%' 1/4W metal films from ebay where a few were 1.5%-2% out.

author: zapta
author_rank: Super Contributor
timestamp: November 17, 2013, 04:02:31 am
content: Quote from: olsenn on November 14, 2013, 03:20:50 amHere is an idea for DMM vendors. Have a 1% and 5% standard resistors and instead of 45.986k show 47K - 2.2%.