Hi
I needed to look into distribution of accuracy of resistors.
Vendors don't have any info, but luckily some nice people online have
done measurements:
https://www.eevblog.com/forum/projects/smd-resistor-distributions/
https://lambdafox.com/resistor-tolerances/
Regards
Klaus
Hi
I needed to look into distribution of accuracy of resistors.
Vendors don't have any info, but luckily some nice people online have
done measurements:
<https://www.eevblog.com/forum/projects/smd-resistor-distributions/>
<https://lambdafox.com/resistor-tolerances/>
On Sat, 27 Apr 2024 00:54:41 +0200, Klaus Vestergaard Kragelund ><klauskvik@hotmail.com> wrote:
HiThe thing to be aware of is that resistor value distributions are
I needed to look into distribution of accuracy of resistors.
Vendors don't have any info, but luckily some nice people online have
done measurements:
<https://www.eevblog.com/forum/projects/smd-resistor-distributions/>
<https://lambdafox.com/resistor-tolerances/>
often wildly non-Gaussian. The classic example is where there are
grades, say 1%, 5%, and 20%. The 5% group will often have a hole that >happens to match the 1% distribution perfectly.
A lot of modern resistors are made with a relatively wide
distribution, and then machine-sorted into bins. In this case, many
of the bins will have uniform distributions. And so on.
Joe Gwinn
On Fri, 26 Apr 2024 20:16:48 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
On Sat, 27 Apr 2024 00:54:41 +0200, Klaus Vestergaard Kragelund >><klauskvik@hotmail.com> wrote:
HiThe thing to be aware of is that resistor value distributions are
I needed to look into distribution of accuracy of resistors.
Vendors don't have any info, but luckily some nice people online have >>>done measurements:
<https://www.eevblog.com/forum/projects/smd-resistor-distributions/>
<https://lambdafox.com/resistor-tolerances/>
often wildly non-Gaussian. The classic example is where there are
grades, say 1%, 5%, and 20%. The 5% group will often have a hole that >>happens to match the 1% distribution perfectly.
A lot of modern resistors are made with a relatively wide
distribution, and then machine-sorted into bins. In this case, many
of the bins will have uniform distributions. And so on.
Joe Gwinn
I suspect that they may laser trimmed and shipped, not binned.
One batch on a reel could be very close to one another.
On Sat, 27 Apr 2024 16:47:29 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
On Fri, 26 Apr 2024 19:38:07 -0700, John Larkin >><jjSNIPlarkin@highNONOlandtechnology.com> wrote:
On Fri, 26 Apr 2024 20:16:48 -0400, Joe Gwinn <joegwinn@comcast.net> >>>wrote:
On Sat, 27 Apr 2024 00:54:41 +0200, Klaus Vestergaard Kragelund >>>><klauskvik@hotmail.com> wrote:
HiThe thing to be aware of is that resistor value distributions are
I needed to look into distribution of accuracy of resistors.
Vendors don't have any info, but luckily some nice people online have >>>>>done measurements:
<https://www.eevblog.com/forum/projects/smd-resistor-distributions/>
<https://lambdafox.com/resistor-tolerances/>
often wildly non-Gaussian. The classic example is where there are >>>>grades, say 1%, 5%, and 20%. The 5% group will often have a hole that >>>>happens to match the 1% distribution perfectly.
A lot of modern resistors are made with a relatively wide
distribution, and then machine-sorted into bins. In this case, many
of the bins will have uniform distributions. And so on.
Joe Gwinn
I suspect that they may laser trimmed and shipped, not binned.
One batch on a reel could be very close to one another.
Also possible, and maybe a combination of both?
But the fundamental point is that one must measure to be sure, unless
one is a large enough customer that the manufacturer will simply tell
you.
Joe Gwinn
We just assume that all 1% resistors are within 1%.
We buy 0.1% and some 0.05% parts too. Since most of our products have >software-based calibration, we mostly care about resistor tempcos, not
so much tolerances.
On Sat, 27 Apr 2024 14:24:43 -0700, John Larkin ><jjSNIPlarkin@highNONOlandtechnology.com> wrote:
On Sat, 27 Apr 2024 16:47:29 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
On Fri, 26 Apr 2024 19:38:07 -0700, John Larkin >>><jjSNIPlarkin@highNONOlandtechnology.com> wrote:
On Fri, 26 Apr 2024 20:16:48 -0400, Joe Gwinn <joegwinn@comcast.net> >>>>wrote:
On Sat, 27 Apr 2024 00:54:41 +0200, Klaus Vestergaard Kragelund >>>>><klauskvik@hotmail.com> wrote:
HiThe thing to be aware of is that resistor value distributions are >>>>>often wildly non-Gaussian. The classic example is where there are >>>>>grades, say 1%, 5%, and 20%. The 5% group will often have a hole that >>>>>happens to match the 1% distribution perfectly.
I needed to look into distribution of accuracy of resistors.
Vendors don't have any info, but luckily some nice people online have >>>>>>done measurements:
<https://lambdafox.com/resistor-tolerances/><https://www.eevblog.com/forum/projects/smd-resistor-distributions/> >>>>>>
A lot of modern resistors are made with a relatively wide >>>>>distribution, and then machine-sorted into bins. In this case, many >>>>>of the bins will have uniform distributions. And so on.
Joe Gwinn
I suspect that they may laser trimmed and shipped, not binned.
One batch on a reel could be very close to one another.
Also possible, and maybe a combination of both?
But the fundamental point is that one must measure to be sure, unless
one is a large enough customer that the manufacturer will simply tell >>>you.
Joe Gwinn
We just assume that all 1% resistors are within 1%.
We buy 0.1% and some 0.05% parts too. Since most of our products have >>software-based calibration, we mostly care about resistor tempcos, not
so much tolerances.
Yes, and calibration will wash all those strange-distribution woes
away.
Joe Gwinn
On Fri, 26 Apr 2024 19:38:07 -0700, John Larkin ><jjSNIPlarkin@highNONOlandtechnology.com> wrote:
On Fri, 26 Apr 2024 20:16:48 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
On Sat, 27 Apr 2024 00:54:41 +0200, Klaus Vestergaard Kragelund >>><klauskvik@hotmail.com> wrote:
HiThe thing to be aware of is that resistor value distributions are
I needed to look into distribution of accuracy of resistors.
Vendors don't have any info, but luckily some nice people online have >>>>done measurements:
<https://www.eevblog.com/forum/projects/smd-resistor-distributions/>
<https://lambdafox.com/resistor-tolerances/>
often wildly non-Gaussian. The classic example is where there are >>>grades, say 1%, 5%, and 20%. The 5% group will often have a hole that >>>happens to match the 1% distribution perfectly.
A lot of modern resistors are made with a relatively wide
distribution, and then machine-sorted into bins. In this case, many
of the bins will have uniform distributions. And so on.
Joe Gwinn
I suspect that they may laser trimmed and shipped, not binned.
One batch on a reel could be very close to one another.
Also possible, and maybe a combination of both?
But the fundamental point is that one must measure to be sure, unless
one is a large enough customer that the manufacturer will simply tell
you.
Joe Gwinn
On Sat, 27 Apr 2024 17:41:10 -0400, Joe Gwinn <joegwinn@comcast.net>wrote
On Sat, 27 Apr 2024 14:24:43 -0700, John Larkin <jjSNIPlarkin@highNONOlandtechnology.com> wrote:
On Sat, 27 Apr 2024 16:47:29 -0400, Joe Gwinn <joegwinn@comcast.net> wrote: >>>> On Fri, 26 Apr 2024 19:38:07 -0700, John Larkin <jjSNIPlarkin@highNONOlandtechnology.com> wrote:
On Fri, 26 Apr 2024 20:16:48 -0400, Joe Gwinn <joegwinn@comcast.net> wrote:
On Sat, 27 Apr 2024 00:54:41 +0200, Klaus Vestergaard Kragelund <klauskvik@hotmail.com> wrote:
One could cal out tempcos, but test time would be outrageous.
We are bidding on one unit that might need that. Yuk. The alternative
is to, basically, ovenize the PCB.
| Sysop: | Keyop |
|---|---|
| Location: | Huddersfield, West Yorkshire, UK |
| Users: | 300 |
| Nodes: | 16 (2 / 14) |
| Uptime: | 94:17:58 |
| Calls: | 6,718 |
| Calls today: | 2 |
| Files: | 12,252 |
| Messages: | 5,359,270 |
| Posted today: | 1 |