Funny business with 1% film resistors, not being close to 1%

tegendemuur

tegendemuur

Well-known member
It's not high end what we're doing here, so I thought buying at some adequate electronica shop would yield good components, but when 470k ends up being as low as 457K and as high as 483K (so about 3% tolerance I suppose) I guess I'll have to look elsewhere for my components... What a pain. But falls in line with the chore online purchases have become since the pandemic. Since there's not really a brand thing going on here, where should one look out for instead for good material?

Those Musikding components where super tight with their values...
 
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spi said:
which one?
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A Dutch one that's not really relevant for most here (Open Circuit). Figuring these came from a pack with 30 values, I thought they were cheaper because they consisted of the common values, but they should have just labelled them 3% or whatever. Guess I'll be buying the 10 pieces packs, as those seem to more in line (while looking exactly the same; same tint of blue, thickness of leads.)

(The Musikding one's have thicker leads, and are a bit "fatter" looking - Curious now which brand he uses. Same available at Banzai Music?)
 
Bringing this back to life. Bought a tester finally and seeing 10-20%+ on 1% resistor. 24k was coming in at 19k for 5 in a row. Read the markings and it was 24k. Checked 27k and it came in at 25 and change so used that.

Is this commonplace or did I just buy cheap parts?
 
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Anything bought from Amazon, in my experience, tends towards being out-of-spec with regards to tolerance. More like 5% on what is marked 1%.

I'd imagine that whomever supplies Amazon does a lot of business all over the place. Just bad QC. Or maybe they buy up all the rejected items from the larger manufacturers, repackage em, and send them along.

Royal Ohm from Tayda is good 'nuff. I'm a little bit superstitious, though. I like vishay dale rn55's and CMF55'S, cause they got the value printed on the side and have *really* thick leads.

I won't buy em if they're more than 15 bucks for 100 though. In that case I switch to KOA speers. Leads are nearly as think. Much cheaper too.

It's not the sort of thing that should have any real impact on a successful build, but given how cheaply resistors can be had, is say Chuck the stuff that's out it spec.
 
Stickman393 said:
Anything bought from Amazon, in my experience, tends towards being out-of-spec with regards to tolerance. More like 5% on what is marked 1%.

I'd imagine that whomever supplies Amazon does a lot of business all over the place. Just bad QC. Or maybe they buy up all the rejected items from the larger manufacturers, repackage em, and send them along.

Royal Ohm from Tayda is good 'nuff. I'm a little bit superstitious, though. I like vishay dale rn55's and CMF55'S, cause they got the value printed on the side and have *really* thick leads.

I won't buy em if they're more than 15 bucks for 100 though. In that case I switch to KOA speers. Leads are nearly as think. Much cheaper too.
Slice Master
It's not the sort of thing that should have any real impact on a successful build, but given how cheaply resistors can be had, is say Chuck the stuff that's out it spec.
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It is possible that some of the products are stock or rejected items from larger manufacturers, then repackaged and resold. This happens frequently, and it is the lack of quality control by Amazon sellers that is the main reason for the inconsistent quality of electronic components.
 
If you are holding the resistors against your meter probes with your fingers, you will act like a resistor in parallel and the readings will show as a lower value, especially on higher values resistors.
 
Good to know.

I use a tester I got off Amazon, for get the model, it was ~$30 on sale. Not sure if that could be inaccurate as well.


analogdevice said:
If you are holding the resistors against your meter probes with your fingers, you will act like a resistor in parallel and the readings will show as a lower value, especially on higher values resistors.
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CheapSuitG said:
Good to know.

I use a tester I got off Amazon, for get the model, it was ~$30 on sale. Not sure if that could be inaccurate as well.
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You might check to see if there’s a calibration routine on it as well, both of mine have one and it should be done before first use and periodically thereafter.
 
CheapSuitG said:
Good to know.

I use a tester I got off Amazon, for get the model, it was ~$30 on sale. Not sure if that could be inaccurate as well.
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Always worthwhile to question the accuracy of measuring equipment.

Every now and then I'm stuck at work on a seemingly insurmountable problem, then I check my probes for accuracy, re-calibrate, and feel real dumb cause the problem was just a mirage caused by sensor drift.
 
Digging more into this, doesn’t have a calibration mode.

It is on the latest update though

Still getting 24k at 20.1k

(I’m using that because I don’t remember the 10 others I used that were off)
 

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You're measuring -16.25% off from the stated value there.

Granted, those little multi testers are handy, but they're not always super accurate. My tc-1 has always done fairly well with resistance though.

That kind of deviation makes me suspect the component is at fault here.
 
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