Resistor distribution

[George Herold]

I was killing some time last night before going to my first maker
space meeting, watching some Dave videos.

http://www.eevblog.com/2011/11/08/eevblog-215-gaussian-resistors/
http://www.eevblog.com/2011/11/14/eevblog-216-gaussian-resistor-redux/

In the first video Dave finds that some Philips resistors have a ~
+/-0.5% distribution right around the ‘correct’ value.

In the second he finds that some cheaper (Xicon?) also have a 0.5%
‘spread’, but the average is a bit (~0.35%) lower than nominal.

This raises a bunch of interesting questions.
Do any resistor makers publish this sort of data?
Does buying resistors from a ‘better’ manufacturer lead to resistors
with a better mean.
I use mostly cheap Xicon 1%ers. A few times I’ve gone hunting through
the parts bin with an ohmmeter trying to find some particular value.
Though I don’t have any data I did strike me that the average seemed a
bit low. (When looking for a 10.0k ohm I found many more 9.9X k ohms
than 10.0X k ohms.)

So does anyone know how 1% resistors are made? I find it hard to
believe that they trim each one.
(Do they trim the 0.1% ers?)

George H.

[John Larkin]

On Tue, 8 Jan 2013 06:54:35 -0800 (PST), George Herold <ghe...@teachspin.com>
wrote:

Most 1% or better surface-mount resistors are laser trimmed. You can check them
under magnification and see the trim cuts. If it's done very quickly, the mean
could well be a bit off for any given reel.

Commodity thickfilms can cost under a penny each. I think - not sure - that 5%
thickfilms are generally manufactured without trimming, so a batch of them could
be a percent or two off.

We use the Susumu thinfilms for important stuff. They are very good, in
tolerance, TC, and aging.


--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

[George Herold]

On Jan 8, 10:49 am, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Tue, 8 Jan 2013 06:54:35 -0800 (PST), George Herold <gher...@teachspin.com>

OK Thanks, I guess I can believe the trimming, but do they measure
each one?

George H.

>
> Commodity thickfilms can cost under a penny each. I think - not sure - that 5%
> thickfilms are generally manufactured without trimming, so a batch of them could
> be a percent or two off.
>
> We use the Susumu thinfilms for important stuff. They are very good, in
> tolerance, TC, and aging.
>
> --
>

> John Larkin                  Highland Technology Incwww.highlandtechnology.com  jlarkin at highlandtechnology dot com

>
> Precision electronic instrumentation
> Picosecond-resolution Digital Delay and Pulse generators
> Custom timing and laser controllers
> Photonics and fiberoptic TTL data links
> VME  analog, thermocouple, LVDT, synchro, tachometer

> Multichannel arbitrary waveform generators- Hide quoted text -
>
> - Show quoted text -

[Michael A. Terrell]

John Larkin wrote:
>
> Most 1% or better surface-mount resistors are laser trimmed. You can check them
> under magnification and see the trim cuts. If it's done very quickly, the mean
> could well be a bit off for any given reel.
>
> Commodity thickfilms can cost under a penny each. I think - not sure - that 5%
> thickfilms are generally manufactured without trimming, so a batch of them could
> be a percent or two off.
>
> We use the Susumu thinfilms for important stuff. They are very good, in
> tolerance, TC, and aging.

I bought some Susumu thinfilms for under a buck a reel of 5000.

[Michael A. Terrell]

George Herold wrote:
>
> OK Thanks, I guess I can believe the trimming, but do they measure
> each one?

How can they trim them if they don't?

[John Larkin]

On Tue, 8 Jan 2013 09:02:15 -0800 (PST), George Herold <ghe...@teachspin.com>
wrote:

Sure; they laser cut until the value is right. It's often an L cut; the cross
axis is coarse trim, and the longitudinal cut is final fine trim.

--

John Larkin Highland Technology Inc

www.highlandtechnology.com jlarkin at highlandtechnology dot com

[John Larkin]

Good deal. They are usually about 30 cents each.

[George Herold]

On Jan 8, 12:14 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:

I could imagine that they measure a few to set the laser cut and then
only do spot checks. But I clearly have no clue how it's done!
It sorta blows my mind to think someone can make it, measure it, trim
it, and then sell it to me for under a penny.

George H.

[George Herold]

On Jan 8, 12:31 pm, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Tue, 8 Jan 2013 09:02:15 -0800 (PST), George Herold <gher...@teachspin.com>

Well I scrapped the silk screen off the surface of a few and an L cut
was exactly what I saw.

I think there is a Vishay resistor plant somewhere near me... I wonder
if I could get a tour?

George H.
>
> --
>
> John Larkin                  Highland Technology Incwww.highlandtechnology.com  jlarkin at highlandtechnology dot com

>
> Precision electronic instrumentation
> Picosecond-resolution Digital Delay and Pulse generators
> Custom timing and laser controllers
> Photonics and fiberoptic TTL data links
> VME  analog, thermocouple, LVDT, synchro, tachometer

[John Larkin]

A laser trimmer must be cool to see. The parts are flying through some
handler/measuring gadget and being laser blasted at some number per
second. Time matters, so there is probably some empirical
second-guessing of subsequent thermal and other creep-back.


--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com

http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators

Custom laser drivers and controllers

Photonics and fiberoptic TTL data links

VME thermocouple, LVDT, synchro acquisition and simulation

[Michael A. Terrell]

George Herold wrote:
>
> On Jan 8, 12:14 pm, "Michael A. Terrell" ?mike.terr...@earthlink.net?
> wrote:
> ? George Herold wrote:
> ?
> ? ? OK Thanks, I guess I can believe the trimming, but do they measure
> ? ? each one?
> ?

> ? How can they trim them if they don't?
>
> I could imagine that they measure a few to set the laser cut and then
> only do spot checks. But I clearly have no clue how it's done!
> It sorta blows my mind to think someone can make it, measure it, trim
> it, and then sell it to me for under a penny.

All done by machines.

[Fred Bartoli]

Michael A. Terrell a �crit :

Selling too?

--
Thanks,
Fred.

[Jeroen]

Sort of: Droids.

Jeroen Belleman

[Michael A. Terrell]

Fred Bartoli wrote:
>
> Michael A. Terrell a �crit :

> ? George Herold wrote:
> ?? On Jan 8, 12:14 pm, "Michael A. Terrell" ?mike.terr...@earthlink.net?
> ?? wrote:
> ?? ? George Herold wrote:
> ?? ?
> ?? ? ? OK Thanks, I guess I can believe the trimming, but do they measure
> ?? ? ? each one?
> ?? ?
> ?? ? How can they trim them if they don't?
> ??
> ?? I could imagine that they measure a few to set the laser cut and then
> ?? only do spot checks. But I clearly have no clue how it's done!
> ?? It sorta blows my mind to think someone can make it, measure it, trim
> ?? it, and then sell it to me for under a penny.
> ?
> ?
> ? All done by machines.
>
> Selling too?


By computer? Yes. I haven't bought electronics parts in person or
over the phone in over 20 years. :)

[Michael A. Terrell]

Jeroen wrote:
>
> On 2013-01-08 21:17, Fred Bartoli wrote:

> ? Michael A. Terrell a �crit :
> ?? George Herold wrote:
> ??? On Jan 8, 12:14 pm, "Michael A. Terrell" ?mike.terr...@earthlink.net?
> ??? wrote:
> ??? ? George Herold wrote:
> ??? ?
> ??? ? ? OK Thanks, I guess I can believe the trimming, but do they measure
> ??? ? ? each one?
> ??? ?
> ??? ? How can they trim them if they don't?
> ???
> ??? I could imagine that they measure a few to set the laser cut and then
> ??? only do spot checks. But I clearly have no clue how it's done!
> ??? It sorta blows my mind to think someone can make it, measure it, trim
> ??? it, and then sell it to me for under a penny.
> ??
> ??
> ?? All done by machines.
> ?
> ? Selling too?
> ?
>
> Sort of: Droids.


Ann & all her fellow machines?

[k...@attt.bizz]

More like six to a penny.

[k...@attt.bizz]

Have you ever seen an operation like DigiKey? ...or Amazon? ...or
NewEgg? Do you really think they have people chasing parts?

[Cydrome Leader]

In sci.electronics.design k...@attt.bizz wrote:
> On Tue, 08 Jan 2013 21:17:11 +0100, Fred Bartoli <" "> wrote:
>

>>Michael A. Terrell a ?crit :

>>> George Herold wrote:
>>>> On Jan 8, 12:14 pm, "Michael A. Terrell" ?mike.terr...@earthlink.net?
>>>> wrote:
>>>> ? George Herold wrote:
>>>> ?
>>>> ? ? OK Thanks, I guess I can believe the trimming, but do they measure
>>>> ? ? each one?
>>>> ?
>>>> ? How can they trim them if they don't?
>>>>
>>>> I could imagine that they measure a few to set the laser cut and then
>>>> only do spot checks. But I clearly have no clue how it's done!
>>>> It sorta blows my mind to think someone can make it, measure it, trim
>>>> it, and then sell it to me for under a penny.
>>>
>>>
>>> All done by machines.
>>
>>Selling too?
>
> Have you ever seen an operation like DigiKey? ...or Amazon? ...or
> NewEgg? Do you really think they have people chasing parts?

amazon sure has people doing the picking.

[Robert Baer]

Back in the "good old daze" '70s to '90s) 5% carbon comps ran
typically 2% high with a rather tight spread - maybe +/- 1% (to +/- 2%
at most).

[k...@attt.bizz]

The video I saw was all automated.

[George Herold]

On Jan 8, 1:30 pm, John Larkin <jlar...@highlandtechnology.com> wrote:
> On Tue, 8 Jan 2013 09:39:06 -0800 (PST), George Herold
>
>
>
>
>

> jlarkin at highlandtechnology dot comhttp://www.highlandtechnology.com

>
> Precision electronic instrumentation
> Picosecond-resolution Digital Delay and Pulse generators
> Custom laser drivers and controllers
> Photonics and fiberoptic TTL data links

> VME thermocouple, LVDT, synchro   acquisition and simulation- Hide quoted text -

>
> - Show quoted text -

Hey, I was scraping the blue coating off some through hole MF's
Do they laser trim those too, or something else?
I couldn't see much, but when I was done, 10k had become 10.5k.
(I could do in circuit, tweaking with an exacto knife.)

George H.

[George Herold]

On Jan 8, 7:32 pm, Robert Baer <robertb...@localnet.com> wrote:
> Michael A. Terrell wrote:
>
> > Fred Bartoli wrote:
>

> >> Michael A. Terrell a écrit :

> at most).- Hide quoted text -

>
> - Show quoted text -

Interesting, Don't CC's have a terrible tempco. (We used them as low
temp sensors, maybe better near RT.)

[Spehro Pefhany]

Spiral grinding of cheap leaded resistors:

http://www.mfrelectronics.com/cut.jpg

If I was them, I wouldn't be talking about the mercury contacts.



Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

[Spehro Pefhany]

On Tue, 08 Jan 2013 21:17:11 +0100, the renowned Fred Bartoli <" ">
wrote:

I recall one of the local disties back years ago decided to stop
carrying resistors-- their bean counters figured it was something like
80% of their costs for 20% of their volume, and they wanted to
concentrate on high-markup semiconductors. No longer around, natch.

[George Herold]

On Jan 8, 8:10 pm, Spehro Pefhany <speffS...@interlogDOTyou.knowwhat>
wrote:

> On Tue, 08 Jan 2013 13:39:13 -0500, the renowned "Michael A. Terrell"
>
>
>
>
>
> <mike.terr...@earthlink.net> wrote:
>
> >George Herold wrote:
>
> >> On Jan 8, 12:14 pm, "Michael A. Terrell" ?mike.terr...@earthlink.net?
> >> wrote:
> >> ? George Herold wrote:
> >> ?
> >> ? ? OK Thanks,  I guess I can believe the trimming, but do they measure
> >> ? ? each one?
> >> ?
> >> ?    How can they trim them if they don't?
>
> >> I could imagine that they measure a few to set the laser cut and then
> >> only do spot checks.  But I clearly have no clue how it's done!
> >> It sorta blows my mind to think someone can make it, measure it, trim
> >> it, and then sell it to me for under a penny.
>
> >   All done by machines.
>
> Spiral grinding of cheap leaded resistors:
>
> http://www.mfrelectronics.com/cut.jpg

Neat, Thanks. (I take it those are spitting out 1% metal film
resistors.)

>
> If I was them, I wouldn't be talking about the mercury contacts.

Hmm, how else are you going to make contact to the spinning lead?

(there's some indium gallium... ? tin? alloy that melts below 100C.)

Got it, Field's metal. (I assume named after our own John
Fields :^)

George H.

>
> Best regards,
> Spehro Pefhany
> --
> "it's the network..."                          "The Journey is the reward"
> sp...@interlog.com             Info for manufacturers:http://www.trexon.com

> Embedded software/hardware/analog  Info for designers:  http://www.speff.com- Hide quoted text -

[George Herold]

oops.. nope it is indium gallium and tin... Galinstan.

Geo

> George H.
>
>
>
>
>
> > Best regards,
> > Spehro Pefhany
> > --
> > "it's the network..."                          "The Journey is the reward"
> > sp...@interlog.com             Info for manufacturers:http://www.trexon.com

> > Embedded software/hardware/analog  Info for designers:  http://www.speff.com-Hide quoted text -
>
> > - Show quoted text -- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -

[Robert Baer]

George Herold wrote:
> On Jan 8, 7:32 pm, Robert Baer<robertb...@localnet.com> wrote:
>> Michael A. Terrell wrote:
>>
>>> Fred Bartoli wrote:
>>

>>>> Michael A. Terrell a �crit :

The more modern Ohmite carbon comps were about 5 times better that
the really old ones that had the leads spiral wrapped around the ends..
The 47 to 100 ohm Ohmites were very nice as fuses / overload
indicators when placed in the cathode of series power regulator tubes.
Discoloration "level" would indicate a certain amount of overload,
and next cracking to open, and then carbonizaton and finally "busted black".

[Michael A. Terrell]

Spehro Pefhany wrote:
>
> On Tue, 08 Jan 2013 21:17:11 +0100, the renowned Fred Bartoli ?" "?
> wrote:
>
> ?Michael A. Terrell a �crit :

> ?? George Herold wrote:
> ??? On Jan 8, 12:14 pm, "Michael A. Terrell" ?mike.terr...@earthlink.net?
> ??? wrote:
> ??? ? George Herold wrote:
> ??? ?
> ??? ? ? OK Thanks, I guess I can believe the trimming, but do they measure
> ??? ? ? each one?
> ??? ?
> ??? ? How can they trim them if they don't?
> ???
> ??? I could imagine that they measure a few to set the laser cut and then
> ??? only do spot checks. But I clearly have no clue how it's done!
> ??? It sorta blows my mind to think someone can make it, measure it, trim
> ??? it, and then sell it to me for under a penny.
> ??
> ??
> ?? All done by machines.
> ?

> ?Selling too?

>
> I recall one of the local disties back years ago decided to stop
> carrying resistors-- their bean counters figured it was something like
> 80% of their costs for 20% of their volume, and they wanted to
> concentrate on high-markup semiconductors. No longer around, natch.

That's like the distributors who tried a $50 minimum order for repair
parts. They claimed they couldn't afford to keep filling $20 minimum
orders. It didn't last very long before they either went back to $20,
dropped any minimum or closed their doors.

[Michael A. Terrell]

Robert Baer wrote:
>
> Back in the "good old daze" '70s to '90s) 5% carbon comps ran
> typically 2% high with a rather tight spread - maybe +/- 1% (to +/- 2%
> at most).

How accurate was your meter?

[Phil Allison]

"George Herold"

In the first video Dave finds that some Philips resistors have a ~
+/-0.5% distribution right around the �correct� value.

In the second he finds that some cheaper (Xicon?) also have a 0.5%
�spread�, but the average is a bit (~0.35%) lower than nominal.

This raises a bunch of interesting questions.
Do any resistor makers publish this sort of data?

** The tolerance percentage includes a nominal service life - so a nominal
1% tolerance part is usually much tighter when new. That is all that is
being claimed.

Does buying resistors from a �better� manufacturer lead to resistors
with a better mean.

** Pointless even reseching it as it would be a moving target.

So does anyone know how 1% resistors are made? I find it hard to
believe that they trim each one.

** That spiral cut does not get there by itself and the cutting machine
stops when the value is right.

Tighter tolerances ( than say 1%) requires slower operation and or the use
of a laser - so the parts cost more.


.... Phil

[Jasen Betts]

On 2013-01-09, George Herold <ghe...@teachspin.com> wrote:
> On Jan 8, 8:10 pm, Spehro Pefhany <speffS...@interlogDOTyou.knowwhat>
> wrote:
>> On Tue, 08 Jan 2013 13:39:13 -0500, the renowned "Michael A. Terrell"
>

> Neat, Thanks. (I take it those are spitting out 1% metal film
> resistors.)

carbon film also has a spiral cut.

>>
>> If I was them, I wouldn't be talking about the mercury contacts.
>
> Hmm, how else are you going to make contact to the spinning lead?
>

how about carbon, or copper, brushes: two each end so you can make a
kelvin measurement.

Whatever you use cutting is going to cause localised heating so you'll
have thermocouple effects messing with your measurements, for small
resistors you'll probably have to use AC to counter that.


--
⚂⚃ 100% natural

--- news://freenews.netfront.net/ - complaints: ne...@netfront.net ---

[Fred Bartoli]

George Herold a �crit :

> On Jan 8, 8:10 pm, Spehro Pefhany <speffS...@interlogDOTyou.knowwhat>
> wrote:
>> On Tue, 08 Jan 2013 13:39:13 -0500, the renowned "Michael A. Terrell"
>>
>>
>>
>>
>>
>> <mike.terr...@earthlink.net> wrote:
>>
>>> George Herold wrote:
>>>> On Jan 8, 12:14 pm, "Michael A. Terrell" ?mike.terr...@earthlink.net?
>>>> wrote:
>>>> ? George Herold wrote:
>>>> ?
>>>> ? ? OK Thanks, I guess I can believe the trimming, but do they measure
>>>> ? ? each one?
>>>> ?
>>>> ? How can they trim them if they don't?
>>>> I could imagine that they measure a few to set the laser cut and then
>>>> only do spot checks. But I clearly have no clue how it's done!
>>>> It sorta blows my mind to think someone can make it, measure it, trim
>>>> it, and then sell it to me for under a penny.
>>> All done by machines.
>> Spiral grinding of cheap leaded resistors:
>>
>> http://www.mfrelectronics.com/cut.jpg
>
> Neat, Thanks. (I take it those are spitting out 1% metal film
> resistors.)
>
>> If I was them, I wouldn't be talking about the mercury contacts.
>
> Hmm, how else are you going to make contact to the spinning lead?
>

Lots of ways. For ex, after a first meas, which you probably even can
infer from the previous bulk value(s) in the batch you go near the final
cut position, then make contacts with a wire/flex/whatever that have to
withstand limited rotation. Or maybe cover the full angle span with a
spiraled conductor, or brush contacts, or... or...


--
Thanks,
Fred.

[Fred Bartoli]

Spehro Pefhany a �crit :

> On Tue, 08 Jan 2013 13:39:13 -0500, the renowned "Michael A. Terrell"
> <mike.t...@earthlink.net> wrote:
>
>> George Herold wrote:
>>> On Jan 8, 12:14 pm, "Michael A. Terrell" ?mike.terr...@earthlink.net?
>>> wrote:
>>> ? George Herold wrote:
>>> ?
>>> ? ? OK Thanks, I guess I can believe the trimming, but do they measure
>>> ? ? each one?
>>> ?
>>> ? How can they trim them if they don't?
>>>
>>> I could imagine that they measure a few to set the laser cut and then
>>> only do spot checks. But I clearly have no clue how it's done!
>>> It sorta blows my mind to think someone can make it, measure it, trim
>>> it, and then sell it to me for under a penny.
>>
>> All done by machines.
>
> Spiral grinding of cheap leaded resistors:
>
> http://www.mfrelectronics.com/cut.jpg
>
> If I was them, I wouldn't be talking about the mercury contacts.
>
>
>

And that one is supposed to help the customer build confidence...

http://www.mfrelectronics.com/wel.jpg

Or that one that is just like the machines are in the living room...

http://www.mfrelectronics.com/capping.jpg

A friend of mine that once was in charge at Vishay for solving some
quality issues on a production line for high value resistors (in India
IIRC) told some horror stories that just reminds me some of those pics...


--
Thanks,
Fred.

[SoothSayer]

On 9 Jan 2013 08:00:40 GMT, Jasen Betts <ja...@xnet.co.nz> wrote:

>On 2013-01-09, George Herold <ghe...@teachspin.com> wrote:
>> On Jan 8, 8:10�pm, Spehro Pefhany <speffS...@interlogDOTyou.knowwhat>
>> wrote:
>>> On Tue, 08 Jan 2013 13:39:13 -0500, the renowned "Michael A. Terrell"
>>
>> Neat, Thanks. (I take it those are spitting out 1% metal film
>> resistors.)
>
>carbon film also has a spiral cut.

Not always.

>
>>>
>>> If I was them, I wouldn't be talking about the mercury contacts.
>>
>> Hmm, how else are you going to make contact to the spinning lead?
>>
>
>how about carbon, or copper, brushes: two each end so you can make a
>kelvin measurement.
>
>Whatever you use cutting is going to cause localised heating so you'll
>have thermocouple effects messing with your measurements, for small
>resistors you'll probably have to use AC to counter that.

Matching and culling mass production runs of resistor bodies is easy.

They can do (read it) it before coating, terminating and marking, or
they can make it whole, and read it and mark it afterward.

I am sure that for testing lot run values, they use a platinum faced
wiper.

[John Larkin]

He won it in a spelling bee.

[Phil Allison]

"SoothSayer"
>
> Jasen Betts

>
>>carbon film also has a spiral cut.
>
> Not always.

** What an idiotic remark.




.... Phil

[SoothSayer]

On Thu, 10 Jan 2013 18:07:55 +1100, "Phil Allison" <phi...@tpg.com.au>
wrote:

Yours? Yes, it was... your retarded crack was absolutely an idiotic
remark to make.

You grasp of manufacturing processes rests firmly at nil.

[Dennis]

On 8/01/2013 10:54 PM, George Herold wrote:
> I was killing some time last night before going to my first maker
> space meeting, watching some Dave videos.
>
> http://www.eevblog.com/2011/11/08/eevblog-215-gaussian-resistors/
> http://www.eevblog.com/2011/11/14/eevblog-216-gaussian-resistor-redux/
>

> In the first video Dave finds that some Philips resistors have a ~
> +/-0.5% distribution right around the ‘correct’ value.
>
> In the second he finds that some cheaper (Xicon?) also have a 0.5%
> ‘spread’, but the average is a bit (~0.35%) lower than nominal.
>
> This raises a bunch of interesting questions.
> Do any resistor makers publish this sort of data?

> Does buying resistors from a ‘better’ manufacturer lead to resistors
> with a better mean.

> I use mostly cheap Xicon 1%ers. A few times I’ve gone hunting through
> the parts bin with an ohmmeter trying to find some particular value.
> Though I don’t have any data I did strike me that the average seemed a
> bit low. (When looking for a 10.0k ohm I found many more 9.9X k ohms
> than 10.0X k ohms.)
>

> So does anyone know how 1% resistors are made? I find it hard to
> believe that they trim each one.

> (Do they trim the 0.1% ers?)
>
> George H.
>

http://www.youtube.com/watch?v=lEG5jHEMU4I

[George Herold]

> http://www.youtube.com/watch?v=lEG5jHEMU4I- Hide quoted text -

>
> - Show quoted text -

That's cool, Thanks! Looks like about one resistor every second or
two.
So maybe 3x10^7 per year. (I'm still amazed they can make a profit
selling them.)

I wonder how many resistors the average American 'consumes' in a year.

George H.

[Fred Bartoli]

George Herold a écrit :

And that one...
http://www.youtube.com/watch?v=C8mc6bKKkJQ

I particularly love the "spoon coating" at 3:31

--
Thanks,
Fred.

[Spehro Pefhany]

On Thu, 10 Jan 2013 18:22:13 +0100, the renowned Fred Bartoli <" ">
wrote:

Oh, man. All that touching, touching, touching with those henna and
curry-tainted hands. I think this kind of place only exists because of
historical 40% duties into India and non-tariff barriers such as
military procurement... otherwise the East Asians (especially China)
would put them out of business promptly. Their duty rate now is "only"
18% or so, according to http://www.cybex.in/.

[legg]

On Tue, 08 Jan 2013 20:11:47 -0500, Spehro Pefhany
<spef...@interlogDOTyou.knowwhat> wrote:

>On Tue, 08 Jan 2013 21:17:11 +0100, the renowned Fred Bartoli <" ">
>wrote:
>

>>Michael A. Terrell a écrit :
>>> George Herold wrote:
<snip>

>>> All done by machines.
>>
>>Selling too?
>
>I recall one of the local disties back years ago decided to stop
>carrying resistors-- their bean counters figured it was something like
>80% of their costs for 20% of their volume, and they wanted to
>concentrate on high-markup semiconductors. No longer around, natch.
>
>
>Best regards,
>Spehro Pefhany

And the distie???

You've got to get them into the store buying basics, before you can
flog the high-markup crap.

RL

[k...@attt.bizz]

On Thu, 10 Jan 2013 17:39:33 -0500, legg <le...@nospam.magma.ca> wrote:

>On Tue, 08 Jan 2013 20:11:47 -0500, Spehro Pefhany
><spef...@interlogDOTyou.knowwhat> wrote:
>
>>On Tue, 08 Jan 2013 21:17:11 +0100, the renowned Fred Bartoli <" ">
>>wrote:
>>

>>>Michael A. Terrell a �crit :

>>>> George Herold wrote:
><snip>
>>>> All done by machines.
>>>
>>>Selling too?
>>
>>I recall one of the local disties back years ago decided to stop
>>carrying resistors-- their bean counters figured it was something like
>>80% of their costs for 20% of their volume, and they wanted to
>>concentrate on high-markup semiconductors. No longer around, natch.
>>
>>
>>Best regards,
>>Spehro Pefhany
>
>And the distie???

The disty switches brands. They don't like selling what they can't
get, either.

>You've got to get them into the store buying basics, before you can
>flog the high-markup crap.

Loss leader.

[Spehro Pefhany]

Z*ntronics.. many, many years ago, before Bill Ford went off and
started Tech-Trek.

[Spehro Pefhany]

On Thu, 10 Jan 2013 19:19:51 -0500, the renowned k...@attt.bizz wrote:

>
>Loss leader.

That's pretty much it. The grocery store has to sell milk at a very
competitive price. So they stick it WAAAY in the back so you have to
walk past all kinds of high-margin stuff.

[Tim Wescott]

On Tue, 08 Jan 2013 06:54:35 -0800, George Herold wrote:

> I was killing some time last night before going to my first maker space
> meeting, watching some Dave videos.
>
> http://www.eevblog.com/2011/11/08/eevblog-215-gaussian-resistors/
> http://www.eevblog.com/2011/11/14/eevblog-216-gaussian-resistor-redux/
>
> In the first video Dave finds that some Philips resistors have a ~
> +/-0.5% distribution right around the ‘correct’ value.
>
> In the second he finds that some cheaper (Xicon?) also have a 0.5%
> ‘spread’, but the average is a bit (~0.35%) lower than nominal.
>
> This raises a bunch of interesting questions. Do any resistor makers
> publish this sort of data? Does buying resistors from a ‘better’
> manufacturer lead to resistors with a better mean.
> I use mostly cheap Xicon 1%ers. A few times I’ve gone hunting through
> the parts bin with an ohmmeter trying to find some particular value.
> Though I don’t have any data I did strike me that the average seemed a
> bit low. (When looking for a 10.0k ohm I found many more 9.9X k ohms
> than 10.0X k ohms.)
>
> So does anyone know how 1% resistors are made? I find it hard to
> believe that they trim each one.
> (Do they trim the 0.1% ers?)

I remember a prof of mine telling a story about how in the 1960's or
1970's he decided to save a bunch of money on 1% resistors by buying a
bunch of 5% (or maybe 10% -- I can't remember) resistors and sorting out
the ones that were close to the 1% values.

What he found was a batch of resistors whose distribution was a bell-
curve-with-holes. He concluded that the manufacturer had the same bright
idea before he did.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

[Greegor]

RESISTORS INDIA

http://www.youtube.com/watch?v=C8mc6bKKkJQ

[George Herold]

> Tim Wescott, Communications, Control, Circuits & Softwarehttp://www.wescottdesign.com- Hide quoted text -

>
> - Show quoted text -

Hi Tim, I’ve heard that story so many times. I wonder if it’s just an
urban legend?
(Has any one every seen for themselves the fabled ‘hole’ in the
resistor distribution?)
Hey I’ve got this old case of carbon comp resistors.
From a physics Prof. (RIP)
http://bayimg.com/kAiCFAaEH

The 4.7Meg drawer had a bunch in there so I measured those.
(4.7 Meg, 1/2 Watt, 10%)

About 30 resistors, values ranged from 4.36 to 4.71
Here’s the data,
http://bayimg.com/LaiCdAaeh

No obvious hole at 4.7... but not much data either.

George H.

[dca...@krl.org]

On Jan 11, 9:13 am, George Herold <gher...@teachspin.com> wrote:

> > What he found was a batch of resistors whose distribution was a bell-
> > curve-with-holes.  He concluded that the manufacturer had the same bright
> > idea before he did.
>

> Hi Tim, I’ve heard that story so many times.  I wonder if it’s just an
> urban legend?
> (Has any one every seen for themselves the fabled ‘hole’ in the
> resistor distribution?)

> George H.

Not an urban legend, but............... The manufacturers used to
make the best resistors that they could and then sort them. So you
could end up with a hole in a normal distribution. But as the
manufacturers got better, they had more 1 % resistors than they had a
market for them. So some of the 1 % resistors were sold as 5 %
resistors.

The same thing applies to semiconductors where one can buy say low
leakage diodes in different grades. The manufacturer makes the best
ones it can and then sorts for the higher grades.


Dan

[George Herold]

On Jan 11, 9:27 am, "dcas...@krl.org" <dcas...@krl.org> wrote:
> On Jan 11, 9:13 am, George Herold <gher...@teachspin.com> wrote:
>
> > > What he found was a batch of resistors whose distribution was a bell-
> > > curve-with-holes.  He concluded that the manufacturer had the same bright
> > > idea before he did.
>
> > Hi Tim, I’ve heard that story so many times.  I wonder if it’s just an
> > urban legend?
> > (Has any one every seen for themselves the fabled ‘hole’ in the
> > resistor distribution?)
> > George H.
>
> Not an urban legend, but...............  The manufacturers used to
> make the best resistors that they could and then sort them.  So you
> could end up with a hole in a normal distribution.  But as the
> manufacturers got better, they had more 1 % resistors than they had a
> market for them.  So some of the 1 % resistors were sold as 5 %
> resistors.

Hmm OK, do you have some personal knowledge? So maybe it was only for
a few years that there was a hole in the distribution? (My old
resitor box doesn't have any old 5% ers, Maybe there is no hole in
the 10% R's?)

Seems if you had a excess of 1% resistors then you should lower the
price.

George H.

[k...@attt.bizz]

The same applies to microprocessors, and I'm sure memory. As they get
better at producing the parts the yield of the higher speed/lower
power parts goes up. Of course the orders are for what they are. The
two have to match somehow. One can adjust price and specs to get them
in line over the long run but in the short run one goes into battle
with the weapons one has.

[josephkk]

On Fri, 11 Jan 2013 06:27:55 -0800 (PST), "dca...@krl.org"
<dca...@krl.org> wrote:

Suddenly, i suspect that this was/is a short term stopgap method to ship
sufficient quantity of the tighter tolerance units used by various
manufacturers as they got their processes under better control.

?-)

[Tom Del Rosso]

John Larkin wrote:
>
> Most 1% or better surface-mount resistors are laser trimmed. You can
> check them under magnification and see the trim cuts. If it's done
> very quickly, the mean could well be a bit off for any given reel.

But even if the mean is off, they are still in tolerance, right?


--

Reply in group, but if emailing add one more
zero, and remove the last word.

[John Larkin]

On Sat, 12 Jan 2013 13:43:40 -0500, "Tom Del Rosso"
<tom...@verizon.net.invalid> wrote:

>John Larkin wrote:
>>
>> Most 1% or better surface-mount resistors are laser trimmed. You can
>> check them under magnification and see the trim cuts. If it's done
>> very quickly, the mean could well be a bit off for any given reel.
>
>But even if the mean is off, they are still in tolerance, right?

Good ones are! I think all the 1% resistors that I checked lately were well
within 1%. A reel is usually clustered around some mean value that's a bit off.

But lots of people make cheap resistors. I sure somebody does it badly.




--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators

Custom timing and laser controllers

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