Color of tolerance band on resistors

[legend killer]

Hello everyone,
I was trying to learn about the color bands on resistors and how they can be decoded to find the value of resistance. I went through many websites and books and I've learnt quite a bit. One thing, though, is not quite clear- color of tolerance band.
In many color charts given on the web, the color of tolerance band given are only gold, silver, brown, red, orange, yellow and they show markings like "-" for all other colors, for which I assume those colors are not used to indicate tolerance bands.
On other websites and books, they also show tolerance values for blue, grey and violet and show "-" in front of orange and yellow.
So I am a little confused about what colors are used to indicate tolerance and what colors are not used.
Any one can throw some light on it, it would be really helpful
Regards
LK

 

[cowboybob]

I've always followed a chart like this:
https://www.digikey.com/en/resource...version-calculator-resistor-color-code-4-band
(note the 4, 5 and 6 band resistance/tolerance tools).

As a backup for the above, should I encounter a "weirdo" resistor:
https://webstore.iec.ch/webstore/webstore.nsf/artnum/033377!openDocument.

Honestly, though, if I'm putting together a circuit where tolerance is an issue (say, a bandpass filter or an RC oscillator), I measure the resistor. Otherwise, I don't really care.

The tolerance value(s) are "ballpark" because they are almost universally a + or - (i.e., a range).

 

[KeepItSimpleStupid]

No band is 20%. That's rare, but in vintage equipment it was common.

Once, only once did I see a Zener diode marked with color bands like a resistor.

 

[throbscottle]

I read an article a while ago saying that the author had discovered (years ago when 10% was common and 1% was rare) that 10% resistors do not include any values within 5% of the value - they were all between +/- 5% and +/- 10%. Obviously the mfr had graded their resistors and marked accordingly. There was no comment as to whether it's still done this way. But potentially it's something to bear in mind.

 

[throbscottle]

What also springs to mind is that quite often you will find inside equipment, inductors and capacitors that look like resistors. You get to recognise them after a while, but at first it's quite confusing.

 

[Nigel Goodwin]

Once, only once did I see a Zener diode marked with color bands like a resistor.

I've seen lot's, but only fitted in manufactured equipment - presumably ordered marked that way specifically?.

 

[KeepItSimpleStupid]

I actually got or bought one. Guys at a relatively local HP/Agilent (Not Keysight now) plant helped me figure out why a circuit would not work. It was in 1972, so I can't remember. It was about 20 miles away. Now it's down the road about 2 miles.

 

[Scotophor]

What also springs to mind is that quite often you will find inside equipment, inductors and capacitors that look like resistors. You get to recognise them after a while, but at first it's quite confusing.

These usually have a body color different than the usual beige resistor body. Look for components with a green body, perhaps shorter and fatter than a typical 1/4 watt resistor body, to be inductors. I believe the capacitors typically have dark red or orange bodies.

 

[throbscottle]

I have some axial capacitors in my junk box about the size of 1/8th watt resistors, beige bodies, but no distinguishable end caps. Body colour is no reliable indicator. I've also seen axial inductors on eBay with beige bodies, I think I've seen blue as well. Though I think yes, the vast majority are green. Usually they have different proportions to resistors, and fatter end caps.

 

[legend killer]

Hello everyone,
Thanks for your input.
Regarding the color of tolerance bands, I guess the following colors are used.

When the resistor has four bands, it indicates standard precision resistors. The tolerance of standard precision resistors range from 2% to 20%. Hence possible colors of tolerance band for four band resistors must be red, orange, yellow, gold, silver with their tolerance being 2,3,4,5,10% respectively.

If the resistor has five bands, it indicates high precision resistor. Its tolerance is less than 1%. Hence for five band resistors, the colors used in tolerance band must be green,blue, violet and gray with their respective tolerance being 0.5, 0.25, 0.1 and 0.05 respectively.

What do u say?

 

[Scotophor]

According to Wikipedia those numbers are mostly right, except there is no 3% or 4%, and yellow is only sometimes used as a substitute for gold at 5%. If you have a resistor with an orange tolerance band, it may be intended as either red or yellow -- sometimes the colors are remarkably far from standard, even for those of us with normal color vision. Or it may not be a tolerance code at all, but indicating a 15 ppm/K temperature coefficient.

Tolerance of 1% is available too, brown 5th band.

 

[KeepItSimpleStupid]

You might also note that there are "preferred" values in each series of precision. See https://www.logwell.com/tech/components/resistor_values.html

I learned something: There used to be a 50% tolerance.

 

[legend killer]

Thank you all for the replies.
Srry couldnt post earlier because I wasnt well

 

[legend killer]

I found this link very helpful. The tool also explains you the steps to calculate the resistance values.
**broken link removed**

 

[Paul_L]

I miss the days that I could pick up a resistor and tell you about the resistance, wattage and tolerance. The SMT resistors now I have to measure the resistance, and guess on the rest.

 

[Scotophor]

I thought SMT resistor wattage is fairly standardized based on form factor. (Get out your micrometer...)

 

[John Fairley]

I've always followed a chart like this:
https://www.digikey.com/en/resource...version-calculator-resistor-color-code-4-band
(note the 4, 5 and 6 band resistance/tolerance tools).

As a backup for the above, should I encounter a "weirdo" resistor:
https://webstore.iec.ch/webstore/webstore.nsf/artnum/033377!openDocument.

Honestly, though, if I'm putting together a circuit where tolerance is an issue (say, a bandpass filter or an RC oscillator), I measure the resistor. Otherwise, I don't really care.

The tolerance value(s) are "ballpark" because they are almost universally a + or - (i.e., a range).

Rather than use a chart, you can use a calculator and enter the colors for each band to determine resistance and tolerance. Example: https://www.newark.com/resistor-color-code-calculator

 

[Scotophor]

if I'm putting together a circuit where tolerance is an issue (say, a bandpass filter or an RC oscillator), I measure the resistor. Otherwise, I don't really care.

Sometimes, you should care. Hand-picking a 5% or 10% resistor when you need a value within 1% is asking for trouble. Tolerance ratings not only specify how close a resistor is to its nominal value NOW, they also have some bearing on how close they will remain to that value over temperature changes and after aging. So what happens when your hand-picked within 1% of design spec 10% resistor, drifts in value by +3% in the first year after you installed it?

 

[Willen]

And what about the tolerance of chip (surface mount) resistor? Never I have seen the marking of it in chip resistor.

 

[analog1]

1% are not rare at all in analog design most are 2% RL07 type with reliable temperature coefcient in PS it not uncommon to find resistors of .05% for current detection industries do not by anything higher then 5% and these days of laser trimming resistance the 10,20% will be forever gone