Recognising resistor values

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Ocap Regals

Joined Jan 7, 2017
1
Hello,
I just bough a mix pack of resistor and I am trying to figure out what is their value. I followed the color table but I am still not sure wether I am getting them right. Firstly because I'm never 100% sure which side to start reading the color from and secondly because there seems to be different shades of the same color...Kind of confusing :p Could someone double check to see if I got them right?
 

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dl324

Joined Mar 30, 2015
14,676
Firstly because I'm never 100% sure which side to start reading the color from
Most common resistors come in 1, 2, 5, and 10% tolerance. For them, the last band will be brown, red, gold, or silver, respectively.

Retry reading the values with that in mind and then post your results if you want them checked. I stopped counting after finding a couple incorrect values. It also helps if you're familiar with the standard values for each E (tolerance) family.

You can also use an ohmmeter to check your work...
 

Alec_t

Joined Sep 17, 2013
12,887
The chances are that each resistor is one with a standard (preferred) value. To work out which end is which, it helps to know (or look up) standard values in the E12 and E24 series of resistors. For example, a yellow band next to a mauve band is more likely to denote 47 (a standard value) than it is to denote 74 (which is not a standard value in those series).
 

ian field

Joined Oct 27, 2012
6,536
Hello,
I just bough a mix pack of resistor and I am trying to figure out what is their value. I followed the color table but I am still not sure wether I am getting them right. Firstly because I'm never 100% sure which side to start reading the color from and secondly because there seems to be different shades of the same color...Kind of confusing :p Could someone double check to see if I got them right?
The convention is to have 3 bands bunched together at one end and a 4th band on its own at the other..

Not everyone sticks to convention, all 4 bands may be bunched. Start from the end they're at; 1st digit, 2nd digit, multiplier and tolerance.

There are other variations; very old resistors may only have 3 bands which means tolerance is the next number higher - you probably won't find any of those nowadays.

Any resistor 1% or less is likely to have an extra band - 3 digits instead of 2 + the tolerance band. Those types can be harder to tell which end the bands are closest to - a DMM Ohms range is your friend.
 

hp1729

Joined Nov 23, 2015
2,304
Hello,
I just bough a mix pack of resistor and I am trying to figure out what is their value. I followed the color table but I am still not sure wether I am getting them right. Firstly because I'm never 100% sure which side to start reading the color from and secondly because there seems to be different shades of the same color...Kind of confusing :p Could someone double check to see if I got them right?
Looks good. Yes, confirm it with ammeter. Don't have a meter? Electronic Goldmine has a multi-meter with transistor tester and cable tester for small bucks.
 

MrAl

Joined Jun 17, 2014
9,151
Eh? Seriously? You will pay 18 USD plus shipping when 7 dollar harbor freight dmm will do the job.
Hi,

I get stuff from HF now and then so over the past years i've gotten quite a few things from them. With that in mind, their meters are the worst i have ever had. I'd buy anything else first.

It's known that HF has cheap quality stuff, but some stuff does not matter as much. The non electrical stuff works pretty well. I'e gotten wrenches i still use today, screwdrivers, files, clamps, magnets, other hand tools, some power tools, the power tools might be a little weak but still work pretty well. The exceptions are the two meters i got suck, and the soldering gun i got burnt the tips out after two or three uses so i had to get better tips myself and then the gun overheats.
So i'd get the hand tools, but nothing that has electronics inside it. Sorry to say, but that's the experience i have had and i dont see that changing.
I've also gotten screw sets, tie wraps, pliers, etc., no problems. Just the electronic stuff you have to watch out.
Oh yeah a long time back i got a 100 amp lead acid battery tester, works fine, but that's got an analog meter in it.

That said, testing resistors with a meter is almost mandatory as you dont know if they are marked wrong either.
 

Tonyr1084

Joined Sep 24, 2015
6,877
I'm in 100% agreement with the complaints against Harbor Freight. I've seen people buy stuff there for years and toss them in the garbage in short order. Chicago Electric is another name I've seen with poor results.

On to your question: Resistor color codes are dodgy at best. Depending on their manufacturer, colors do vary in tint and saturation (color and amount of it). It can be difficult for many. For ME ? ? ? It's hell, as I'm partially color blind. Red and green look a lot like brown to me. And purple and blue - the only way I can distinguish the difference between them is to look at the blue and analyze whether I can see any red in the blue. If I think I see red in it then it's violet (purple).

Now, it gets even worse: Buying these unreliable resistors from places that sell stuff, sometimes people buy up factory rejects and market them as new products. And by definition of law, yes, they're new. BUT they're not always going to be good. Not only resistors, but transistors, diodes, IC's - the list can cover just about all electronics. So what you buy at E-Bay or on Amazon, while often you get what you are looking for, I have gotten stuff that are in fact factory rejects. The radio in my wife's car is a factory reject. The volume goes from 0 to 1 to 2 to 2 to 2 to 2 to 8 to 8 to 8 to 9 to 10. From there it's pretty uniform, but if you want just a little louder or a little softer, there IS none. And radio reception is horrible. And I'm stuck with the junk.

I'll use color codes as best I can then use a meter to verify their value. And DVM's (Digital Volt Meters) are cheap enough that you don't have to look for the absolute cheapest. A $7 meter versus an $18 meter ? I'd opt for the more expensive meter just because it's a better meter. No, I wouldn't drop $50 for a meter unless I absolutely depend on it to be accurate and reliable. For the little stuff I mess with - $18 works just fine.

If you buy resistors from an outlet that specializes in these components then you're much more likely to get good resistors with good colors and you can rely on them being more accurate than not. I, too, have bought E-Bay resistors and Digikey resistors. Digikey was more expensive but the quality of the resistors is greatly appreciated. And for being a man who's made a living as an electronics inspector, resistor color codes have been my bane. But with enough light and magnification there was enough color for me to discern whether it was brown, red or green. Blue or purple. The other colors were never a problem. It's only when the color is weak (not bright) that I had to resort to verifying a resistor value on a board using a meter. And then once it's in circuit, you can pretty much forget about touching the leads and getting a reliable resistance. But I managed to be a pretty good inspector all these years.
 

ian field

Joined Oct 27, 2012
6,536
I'm in 100% agreement with the complaints against Harbor Freight. I've seen people buy stuff there for years and toss them in the garbage in short order. Chicago Electric is another name I've seen with poor results.

On to your question: Resistor color codes are dodgy at best. Depending on their manufacturer, colors do vary in tint and saturation (color and amount of it). It can be difficult for many. For ME ? ? ? It's hell, as I'm partially color blind. Red and green look a lot like brown to me. And purple and blue - the only way I can distinguish the difference between them is to look at the blue and analyze whether I can see any red in the blue. If I think I see red in it then it's violet (purple).

.
Sometimes yellow bands can vanish under certain kinds of light.

Up to 10% tolerance; the metallic colour band indicating that made life easy - nowadays less than 5% isn't uncommon, so no metallic band.
 
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