Silly resistor values
Raveninghorde
values used when a value from the E24 range would do just as well.
At the moment I am doing a BOM for a design originating in the US.
Again I note the liberal use of odd resistor values. For example 332k
1%. What is wrong with 330k? Or 102k 1% instead of 100k?
If the value needs to be 102k not 100k why specify 1%?
For production engineering I would always try to use E24 resistors and
always try and mimimize the number of different values.
Is this just a big company attitude that specifies any old vlaue the
calculator comes up with?
Joel Koltner
news:ps6c559ge680laovl...@4ax.com...
> At the moment I am doing a BOM for a design originating in the US.
> Again I note the liberal use of odd resistor values. For example 332k
> 1%. What is wrong with 330k? Or 102k 1% instead of 100k?
Some companies purposely don't use a value from the E24 series when requiring
1% accuracy because it tips off the folks assembling the board that you really
meant 1% resistors -- when just looking at a schematic, it's not always
obvious whether a 1% or 5% part was used. (Personally I try to label things,
e.g., 10.0k rather than 10k if I mean 1%... although this is a somewhat
imperfect approach since labeling a resistor 100.0k seems wrong as it would
imply 0.1% accruacy, but it's not like you're going to label a 5% 100k
resistor at 10e1 either...)
> For production engineering I would always try to use E24 resistors and
> always try and mimimize the number of different values.
There's been some discussion that it makes sense to just stock 1% resistors
rather than both 1% and 5% since these days the price difference is pretty
negligible -- this was the policy at one Very Big Company I once worked for.
(And one of the guys there was the biggest penny pincher you can imagine --
he'd give Joerg a run for his money :-) -- I probably should have paid more
attention to him!)
> Is this just a big company attitude that specifies any old vlaue the
> calculator comes up with?
Well, see above. Also note that while IC designers have it drummed into their
heads that as much as possible everything should be ratioed with no exact
values, in discrete design sometimes 102k really is better than 100k. If you
are just worried about ratios, you might as well use E12 or even E6 values,
regardless of the accuracy needed.
If you're completely confident your assembly guys won't inadvertently
subsitute 5% resistors on you when you mean 1%, I'd say that using 1% E24
values whenever possible makes a lot sense. (Although numerous 1% values
don't exist in the E24 line... e.g., 12k, 16k, etc... this web site has a nice
chart: http://www.logwell.com/tech/components/resistor_values.html).
---Joel
Tim Shoppa
> Whenever I see app notes I have always noted the strange resistor
> values used when a value from the E24 range would do just as well.
>
> At the moment I am doing a BOM for a design originating in the US.
> Again I note the liberal use of odd resistor values. For example 332k
> 1%. What is wrong with 330k? Or 102k 1% instead of 100k?
>
> If the value needs to be 102k not 100k why specify 1%?
>
> For production engineering I would always try to use E24 resistors and
> always try and mimimize the number of different values.
Yeahbut... if they really needed 1% parts, maybe they purposefully
chose some E48 or E96 values to avoid confusion with 5% or 10% values.
There are some specific lines of resistors where E48 and E96 are
available in 0.1%, 0.05% precisions. Digikey stocks many, for example.
So just knowing that it's an E48 value doesn't automatically tell you
that it must be 1%.
Tim.
Joerg
> "Raveninghorde" <raveninghorde@invalid> wrote in message
> news:ps6c559ge680laovl...@4ax.com...
[...]
>
>> For production engineering I would always try to use E24 resistors and
>> always try and mimimize the number of different values.
>
> There's been some discussion that it makes sense to just stock 1% resistors
> rather than both 1% and 5% since these days the price difference is pretty
> negligible -- this was the policy at one Very Big Company I once worked for.
> (And one of the guys there was the biggest penny pincher you can imagine --
> he'd give Joerg a run for his money :-) -- I probably should have paid more
> attention to him!)
>
That's exactly the point. I now do nearly all designs in E96. The lone
exceptions are surge-rated resistors, current sense and other situations
where specialty resistors are required and 5% or 10% really makes a
difference in cost. Or when I need carbon types for high pulse loads.
>> Is this just a big company attitude that specifies any old vlaue the
>> calculator comes up with?
>
> Well, see above. Also note that while IC designers have it drummed into their
> heads that as much as possible everything should be ratioed with no exact
> values, in discrete design sometimes 102k really is better than 100k. If you
> are just worried about ratios, you might as well use E12 or even E6 values,
> regardless of the accuracy needed.
>
You can't really have precise ratios in discrete designs unless you go
to trimmed or specially produced arrays.
> If you're completely confident your assembly guys won't inadvertently
> subsitute 5% resistors on you when you mean 1%, I'd say that using 1% E24
> values whenever possible makes a lot sense. (Although numerous 1% values
> don't exist in the E24 line... e.g., 12k, 16k, etc... this web site has a nice
> chart: http://www.logwell.com/tech/components/resistor_values.html).
>
Best is if the assembly guys get released part numbers and are never
allowed to switch types without at least a deviation signed by
engineering. Otherwise they might swap a surge rated 4.7ohms 5% against
a regular non-surge rated metal film type and one day ... tssss ... *phut*
--
Regards, Joerg
http://www.analogconsultants.com/
"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Sergey Kubushin
> Whenever I see app notes I have always noted the strange resistor
> values used when a value from the E24 range would do just as well.
>
> At the moment I am doing a BOM for a design originating in the US.
> Again I note the liberal use of odd resistor values. For example 332k
> 1%. What is wrong with 330k? Or 102k 1% instead of 100k?
1% resistors are usually made according to E96 range. Making 1% in E24
doesn't make sense because difference between consequtive values is way
bigger than 2% (1% down from the bigger value plus 1% up from the smaller
one) so your E24 1% set is full of holes. Every 5% resistor fits somewhere
in E24 but most of random values won't if you insist on 1%.
That means 332K is a _STANDARD_ value for 1% resistor when 330K is an
oddity.
> If the value needs to be 102k not 100k why specify 1%?
Because it might be 0.5% or 0.1% or something else.
> For production engineering I would always try to use E24 resistors and
> always try and mimimize the number of different values.
>
> Is this just a big company attitude that specifies any old vlaue the
> calculator comes up with?
It is not. E24 1% resistor in the BOM is a crime if this value doesn't exist
in E96. 332K 1% is a stock item while 330K is not.
See e.g. http://www.logwell.com/tech/components/resistor_values.html
---
******************************************************************
* KSI@home KOI8 Net < > The impossible we do immediately. *
* Las Vegas NV, USA < > Miracles require 24-hour notice. *
******************************************************************
Raveninghorde
Sort of makes sense. Someone must use 5% resistors, I haven't, ever.
5% have never offered a measurable cost saving. We pay about �3.50,
about $5.60, a reel for 5000 E24 1%.
Funny though, this design also uses 10k, 100k and 1M in 1%.
Rich Grise
It means the guy that designed the circuit used pots, and tweaked it
within a gnat's ass of the spec, then just ohmed out the pots.
Cheers!
Rich
Raveninghorde
wrote:
I would say that in the UK 330k 1% is standard and ex-stock, 332k 10%
is non standard and will take weeks to get hold of.
Sergey Kubushin
That's weird and makes no sense.
David L. Jones
> Whenever I see app notes I have always noted the strange resistor
> values used when a value from the E24 range would do just as well.
>
> At the moment I am doing a BOM for a design originating in the US.
> Again I note the liberal use of odd resistor values. For example 332k
> 1%. What is wrong with 330k? Or 102k 1% instead of 100k?
Maybe nothing, maybe something, depends on the design.
Just because a value is inside the nominal accuracy does not make it a good
choice, as you are permanately creating an offset bias. Potentially bad news
in say a voltage divider or gain setting network etc.
In the cases you just quoted, 102K 1% is outside the spec of 100K 1% which
most people would use.
> If the value needs to be 102k not 100k why specify 1%?
Because that's standard practice these days. Most people will only stock 1%
parts (regardless of the actual E range) because they are potentially more
useful than 5% or whatever, and probably cheaper and more readily available
depending on the source.
e.g times when I have specified say 5%, I've had purchasing come back often
and say "we can get 1% cheaper, is that ok?"
> For production engineering I would always try to use E24 resistors and
> always try and mimimize the number of different values.
A lot of people stick with E12 simply by habbit. Actually I'd go as far to
say most people, as the majority of designs I see, even today, still use E12
values - usually 1%.
Consolidataing parts in a design is worthwhile, and is often done as a
seperate design step.
> Is this just a big company attitude that specifies any old vlaue the
> calculator comes up with?
There can be many reasons.
For instance, at my current company for new designs we pick values based on
what stock we have and can get, and what parts are in our EDA database
(which includes schematic, verified footprint, 3D model, datasheet, internal
tracking number etc). Adding new parts is a pain, so we pick what's already
available. Almost all of thm are at least 1%, because that is more useful in
more designs.
E12 values are typically picked as a first choice, simply by habbit, because
we happen to have the full range of those in the database, not so with E24
or E96 etc, as parts have just been added "as needed".
Dave.
--
---------------------------------------------
Check out my Electronics Engineering Video Blog & Podcast:
http://www.alternatezone.com/eevblog/
Raveninghorde
wrote:
332k is weird and makes no sense:) That's why I started this thread.
I think it demonstrates the diference between the US and UK
distributors. The UK electronics industry is much smaller that the US.
Joerg
Ahm, reality check, 330K/1%:
Exactly one through-hole type and one 0603 size. No 0805. I wouldn't
exactly call that "popular". Both frigging expensive, my clients would
have me flogged if I squandered the BOM budget that way.
The thru-hole part is made by a little company in Northumberland. Ok,
such a device on a circuit board may be of some sentimental value to a
few folks north of Newcastle upon Tyne ;-)
life imitates life
wrote:
>
>If the value needs to be 102k not 100k why specify 1%?
Although most 1% suppliers include, make, and sell the 5% values in
their E24 1% list, they are not technically a part of the list in most
cases.
life imitates life
wrote:
>Is this just a big company attitude that specifies any old vlaue the
>calculator comes up with?
No. The values have a specific purpose.
You are doing a layout, or you are actually claiming to have
electronics educational background?
You should know why the values are what they are. Think decades.
life imitates life
wrote:
> and 5% or 10% really makes a
>difference in cost.
Only if you are making a million pieces and were stupid enough to buy at
per piece prices.
For anything less than 100 units, the difference is not that great, and
I would much rather stock my proto shop with 1% reels than 5% or jeez...
you said 10%.
Sorry, but you cannot even find 10% resistors in axial, much less SMD.
1% is also the most commonly purchased in short qty as well, so you are
going to find 100 pc bags at a cheaper rate than the "cheaper" resistor
because they charge more if they have to pop open a new spool just to
give you your 45 pcs of a resistor nobody else ever orders in popcorn
quantities.
life imitates life
wrote:
>I would say that in the UK 330k 1% is standard and ex-stock, 332k 10%
>is non standard and will take weeks to get hold of.
He did not say 332k 10% There is no such thing.
THREE significant digits. THINK.
nospam
>> I would say that in the UK 330k 1% is standard and ex-stock, 332k 10%
>> is non standard and will take weeks to get hold of.
>
>
>Ahm, reality check, 330K/1%:
>
>http://uk.farnell.com/jsp/search/browse.jsp?N=500006+1000291+372811+294896&Ntk=gensearch_001&Ntt=resistor&Ntx=&No=0&getResults=true&appliedparametrics=true&locale=en_UK&prevNValues=500006+1000291&originalQueryURL=http%3A%2F%2Fuk.farnell.com%2Fjsp%2Fsearch%2Fbrowse.jsp%3FN%3D500006%2B1000291%26Ntk%3Dgensearch_001%26Ntt%3Dresistor%26Ntx%3D%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Den_UK
>
>Exactly one through-hole type and one 0603 size. No 0805. I wouldn't
>exactly call that "popular". Both frigging expensive, my clients would
>have me flogged if I squandered the BOM budget that way.
>
>The thru-hole part is made by a little company in Northumberland. Ok,
>such a device on a circuit board may be of some sentimental value to a
>few folks north of Newcastle upon Tyne ;-)
Don't think you got the hang of the Farnell (clunky) search engine.
I find 41 330k 1%, in stock, ROHS, not from Newark, fixed resistors (a few
are reels of the same part available singly)
There are only 4 332k 1%, in stock, ROHS, not from Newark, fixed
resistors.
--
David L. Jones
Ah, no actually, you obviously checked the wrong box!
For 330K 1% there are only two as you say with "1%", but 61 items under
"+/-1%" (typical sorting by parameter trap on these websites):
http://uk.farnell.com/jsp/search/browse.jsp?N=500006+1000291+294896+570259&Ntk=gensearch_001&Ntt=resistor&Ntx=&No=0&getResults=true&appliedparametrics=true&locale=en_UK&prevNValues=500006+1000291+294896&originalQueryURL=http%3A%2F%2Fuk.farnell.com%2Fjsp%2Fsearch%2Fbrowse.jsp%3FN%3D500006%2B1000291%26Ntk%3Dgensearch_001%26Ntt%3Dresistor%26Ntx%3D%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Den_UK
11 x 0805, 10 x 0603, 5 x 0402 etc
E12 values in 1% are as common as mud, everyone uses them, mostly due to old
habits as everyone has the E12 range drilled into their head.
Dave.
--
================================================
Nick Cramer
> [ . . . ]
Thanks for the URL, Joel.
--
Nick, KI6VAV. Support severely wounded and disabled Veterans and their
families: https://www.woundedwarriorproject.org/ Thank a Veteran!
Support Our Troops: http://anymarine.com/ You are not forgotten.
Thanks ! ! ~Semper Fi~ USMC 1365061
sv07171024
"Raveninghorde" <raveninghorde@invalid> wrote in message
>
> I would say that in the UK 330k 1% is standard and ex-stock, 332k 10%
> is non standard and will take weeks to get hold of.
Aren't most (if not all) distributors operating worldwide these days?
Raveninghorde
typo. 332k 1%
Raveninghorde
<past...@thebarattheendoftheuniverse.org> wrote:
>On Thu, 09 Jul 2009 18:33:46 +0100, Raveninghorde <raveninghorde@invalid>
>wrote:
>
>>Is this just a big company attitude that specifies any old vlaue the
>>calculator comes up with?
>
> No. The values have a specific purpose.
Yeah, low voltage cut off point for a battery. 1.05V or 0.95V per cell
wouldn't make any difference.
>
> You are doing a layout, or you are actually claiming to have
>electronics educational background?
Left Uni in 1975 and spent my early years at STC working on high rel
amplifiers to pop at the bottom of the ocean for telephone systems
such as TAT-7. I've run my own electronics company since 79.
>
> You should know why the values are what they are. Think decades.
I prefer to think production. Too many different values is a
nuiscence. If I had designed it and need 332k I wold have used 330k
and 2k in series, standard values already in the system.
Robert Baer
JosephKK
<raveninghorde@invalid> wrote:
IME if you order 330k 1% you will get shipped 332k 1%. And unless you
really, really insist and want 1 million pieces, no one will sell you
332k 10% (even then you will still get 332k 1%). It is the on series
value at 1%.
nospam
>IME if you order 330k 1% you will get shipped 332k 1%.
I just checked some wired 330k 1% resistors from my stock and the average
value was around 329k5.
I checked SMT 330k 1% resistors from Panasonic and Neohm and got 329k5 and
328k5.
All the 330k 1% resistors I have were made as 330k resistors not 332k.
If you shipped 332k as 330k you waste 2/3rds of your tolerance and would
have to manufacture and test to 0.3%.
--
Joerg
> On Thu, 09 Jul 2009 14:21:40 -0700, Joerg <inv...@invalid.invalid>
> wrote:
>
>> and 5% or 10% really makes a
>> difference in cost.
>
Please don't quote out of context. This may be why you did not
understand what I wrote.
> Only if you are making a million pieces and were stupid enough to buy at
> per piece prices.
>
I was talking about _specialty_ resistors, not run of the mill stuff.
You may not have been involved in cost critical designs but many of us
must occasionally turn every penny on a design.
> For anything less than 100 units, the difference is not that great, and
> I would much rather stock my proto shop with 1% reels than 5% or jeez...
> you said 10%.
>
> Sorry, but you cannot even find 10% resistors in axial, much less SMD.
>
Huh? One example out of a bazillion:
If the link breaks it's Vishay P/N VR25000002005KA100. And there's more
where that came from ;-)
> 1% is also the most commonly purchased in short qty as well, so you are
> going to find 100 pc bags at a cheaper rate than the "cheaper" resistor
> because they charge more if they have to pop open a new spool just to
> give you your 45 pcs of a resistor nobody else ever orders in popcorn
> quantities.
Hint: Occasionally it is very educational to open a rock-bottom priced
gizmo with a phenolic board in there and take a look what's on that
board. You'll be surprised.
Jim Thompson
wrote:
>life imitates life wrote:
>> On Thu, 09 Jul 2009 14:21:40 -0700, Joerg <inv...@invalid.invalid>
>> wrote:
>>
>>> and 5% or 10% really makes a
>>> difference in cost.
>>
>
>Please don't quote out of context. This may be why you did not
>understand what I wrote.
>
>
[snip]
Pay attention, Joerg... you're debating NymNoNuts.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
Postings via gmail, yahoo, hotmail, aioe, uar or googlegroups, and
troll feeders, are now automatically kill-filed using Agent v5.0
To be white-listed, send request via the E-mail icon on my website
Joel Koltner
news:2o9e559ad5qdedufj...@4ax.com...
"IME if you order 330k 1% you will get shipped 332k 1%."
Not from any of the reputable manufacturers/distributors you won't.
Well, maybe if they know their 332k resistors are really 0.4%, in which case
it could be substituted... although it'd still be a sleazy practice.
Joerg
> On Thu, 09 Jul 2009 17:50:10 -0700, life imitates life
> <past...@thebarattheendoftheuniverse.org> wrote:
>
>> On Thu, 09 Jul 2009 18:33:46 +0100, Raveninghorde <raveninghorde@invalid>
>> wrote:
>>
>>> Is this just a big company attitude that specifies any old vlaue the
>>> calculator comes up with?
>> No. The values have a specific purpose.
>
> Yeah, low voltage cut off point for a battery. 1.05V or 0.95V per cell
> wouldn't make any difference.
>
>> You are doing a layout, or you are actually claiming to have
>> electronics educational background?
>
> Left Uni in 1975 and spent my early years at STC working on high rel
> amplifiers to pop at the bottom of the ocean for telephone systems
> such as TAT-7. I've run my own electronics company since 79.
>
TAT-7 sounds like an interesting project, good old coax. Are you doing a
lot of fiber-optics stuff nowadays?
>> You should know why the values are what they are. Think decades.
>
> I prefer to think production. Too many different values is a
> nuiscence. If I had designed it and need 332k I wold have used 330k
> and 2k in series, standard values already in the system.
I would flag that in a design review. 330K is not part of the E96
series, 332K is.
Benj
> For production engineering I would always try to use E24 resistors and
> always try and mimimize the number of different values.
>
> Is this just a big company attitude that specifies any old vlaue the
> calculator comes up with?
Well you sure don't have a proper "big company attitude" yet, do you?
Where do you suppose all those transistor types came from or all those
tube numbers before that? Why use a standard ANYTHING when you can
change whatever it is just enough that the standard one won't work in
your product anymore and force everyone to come to you for the parts
(with you setting the price, natch).
The idea is always use custom components that are given company part
numbers even when they are standard parts! All parts should always be
referred to on schematics by ONLY a company part number. The link
between any E24 resistors and the company part number (parts should
ONLY bear a part number, never anything else that may give away what
it actually is) should only be found in highly confidential part
specifications indexed only by part numbers and not distributed to
anyone in or outside the company. This secrecy outside the company is
called "extra profit" and inside the company it's called "job
security".
I hope you finally start to get it.
Baron
I smell Mickysoft tactics !
--
Best Regards:
Baron.
Tim Williams
news:h384pf$bve$2...@news.eternal-september.org...
> I smell Mickysoft tactics !
Tektronix has done that forever. They have internal part numbers for
transistors, diodes, resistors, etc. At least they list equivalents where
possible though (e.g., 2N3904).
I suppose Tektronix is the electronic Microsoft: dominated the quality
market for a while, then sold out to crummy equipment and products? ;-)
Tim
--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
Joel Koltner
news:3JN5m.22$Vg7...@newsfe06.iad...
> I suppose Tektronix is the electronic Microsoft: dominated the quality
> market for a while, then sold out to crummy equipment and products? ;-)
Tek's motto used to be, "Committed to excellence."
Now it's "Enabling innovation."
Hmm, OK, but I really think the old one was a stronger statement...
Anyone have a list of company mottos over the years? I would imagine Tek had
more than the two I've listed here, HP must have had a bunch, etc...
Dave Platt
In article <3JN5m.22$Vg7...@newsfe06.iad>,
Tim Williams <tmor...@charter.net> wrote:
>Tektronix has done that forever. They have internal part numbers for
>transistors, diodes, resistors, etc. At least they list equivalents where
>possible though (e.g., 2N3904).
In some cases (ICs and hybrids in particular) these were custom-fabbed
Tektronix-specific parts.
In others, I believe that they were specially tested or selected by or
for Tek - e.g. transistors binned for specific beta ranges or noise
levels, etc.
Some of the Tek schematics I've seen, indicate that certain resistors
were selected on a per-device basis... in effect, per-oscilloscope
trim parts.
--
Dave Platt <dpl...@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!
life imitates life
wrote:
>On Thu, 09 Jul 2009 17:50:10 -0700, life imitates life
><past...@thebarattheendoftheuniverse.org> wrote:
>
>>On Thu, 09 Jul 2009 18:33:46 +0100, Raveninghorde <raveninghorde@invalid>
>>wrote:
>>
>>>Is this just a big company attitude that specifies any old vlaue the
>>>calculator comes up with?
>>
>> No. The values have a specific purpose.
>
>Yeah, low voltage cut off point for a battery. 1.05V or 0.95V per cell
>wouldn't make any difference.
No. That is not the reason.
>
>>
>> You are doing a layout, or you are actually claiming to have
>>electronics educational background?
>
>Left Uni in 1975 and spent my early years at STC working on high rel
>amplifiers to pop at the bottom of the ocean for telephone systems
>such as TAT-7. I've run my own electronics company since 79.
Yet you have no understanding of decades and why the values are what
they are.
>> You should know why the values are what they are. Think decades.
>
>I prefer to think production.
I have been working in the industry for 35 years. I do not think that
ANY resistor value hinders ANYONE in both manufacturing or design.
Anyone that does have a problem with something so petty should not be
working in the industry, much less in a design capacity.
> Too many different values is a
>nuiscence.
No. An abject idiot, however, IS a nuisance.
> If I had designed it and need 332k I wold have used 330k
>and 2k in series,
Which costs more, uses up more precious PCB real estate, and is MORE
DIFFICULT to implement. Combining parts to create a value of resistance
when a single part is available is an order of magnitude more stupid.
> standard values already in the system.
Your company's lethargic, poorly stocked "system"?
The 'standard values' ARE in "the system" The system that the entire
rest of the world uses. D'oh!
I suggest you modify your "system" as well as your mindset.
You are only making things more difficult for yourself, trying to
re-think what the entire industry has already hashed over to oblivion
will not get you there.
life imitates life
wrote:
He listed tolerances for the mil parts, but left out the tempco's?
Oh, and there are 6 band striped axial parts out there as well.
life imitates life
wrote:
>life imitates life wrote:
>> On Thu, 09 Jul 2009 14:21:40 -0700, Joerg <inv...@invalid.invalid>
>> wrote:
>>
>>> and 5% or 10% really makes a
>>> difference in cost.
>>
>
>Please don't quote out of context. This may be why you did not
>understand what I wrote.
>
>
>> Only if you are making a million pieces and were stupid enough to buy at
>> per piece prices.
>>
>
>I was talking about _specialty_ resistors, not run of the mill stuff.
>You may not have been involved in cost critical designs but many of us
>must occasionally turn every penny on a design.
>
>
>> For anything less than 100 units, the difference is not that great, and
>> I would much rather stock my proto shop with 1% reels than 5% or jeez...
>> you said 10%.
>>
>> Sorry, but you cannot even find 10% resistors in axial, much less SMD.
>>
>
>Huh? One example out of a bazillion:
>
>http://www.mouser.com/Search/ProductDetail.aspx?qs=sGAEpiMZZMvhlCB8CTbT5MY5WW0CSN%2fe0p2G%2fHIPcds%3d
>
>If the link breaks it's Vishay P/N VR25000002005KA100. And there's more
>where that came from ;-)
Wink all you want, dumbass. That is a multi-megohm part. It is also a
bulk form power resistor. In fact ALL of them are either high voltage or
power resistors.
Now go find standard values and standard packaging, like SMT that are
less than 1Mohm. You know... part that we all DO use, not some obscure
crap (which I already was aware of).
Get back to me when you find even one.
>
>> 1% is also the most commonly purchased in short qty as well, so you are
>> going to find 100 pc bags at a cheaper rate than the "cheaper" resistor
>> because they charge more if they have to pop open a new spool just to
>> give you your 45 pcs of a resistor nobody else ever orders in popcorn
>> quantities.
>
>
>Hint: Occasionally it is very educational to open a rock-bottom priced
>gizmo with a phenolic board in there and take a look what's on that
>board. You'll be surprised.
Utter nonsense.
scorpius
<To-Email-Use-Th...@My-Web-Site.com> wrote:
>On Fri, 10 Jul 2009 07:54:22 -0700, Joerg <inv...@invalid.invalid>
>wrote:
>
>>life imitates life wrote:
>>> On Thu, 09 Jul 2009 14:21:40 -0700, Joerg <inv...@invalid.invalid>
>>> wrote:
>>>
>>>> and 5% or 10% really makes a
>>>> difference in cost.
>>>
>>
>>Please don't quote out of context. This may be why you did not
>>understand what I wrote.
>>
>>
>[snip]
>
>Pay attention, Joerg... you're debating NymNoNuts.
>
> ...Jim Thompson
Better than acting like a jackass by discussing trolldom with a trollish
retard like you, jerk.
RoyLFuchs
I see a Usenet retard. Again.
The electronics industry was around a lot earlier than Billy was, and
it is not a tactic, you stupid twit. Engineering drove manufacturing,
not some greedy bean counting twit, which is about all you would rate.
The space for the exclamation finalizes the retard moniker you now have
tagged onto yourself.
Good job, typical MS hating retarded asswipe.
RoyLFuchs
<tmor...@charter.net> wrote:
>"Baron" <baron....@linuxmaniac.nospam.net> wrote in message
>news:h384pf$bve$2...@news.eternal-september.org...
>> I smell Mickysoft tactics !
>
>Tektronix has done that forever. They have internal part numbers for
>transistors, diodes, resistors, etc. At least they list equivalents where
>possible though (e.g., 2N3904).
>
>I suppose Tektronix is the electronic Microsoft: dominated the quality
>market for a while, then sold out to crummy equipment and products? ;-)
>
>Tim
I think you are both idiots for giving it such a retarded analysis.
RoyLFuchs
wrote:
>
>In article <3JN5m.22$Vg7...@newsfe06.iad>,
>Tim Williams <tmor...@charter.net> wrote:
>
>>Tektronix has done that forever. They have internal part numbers for
>>transistors, diodes, resistors, etc. At least they list equivalents where
>>possible though (e.g., 2N3904).
>
>In some cases (ICs and hybrids in particular) these were custom-fabbed
>Tektronix-specific parts.
>
>In others, I believe that they were specially tested or selected by or
>for Tek - e.g. transistors binned for specific beta ranges or noise
>levels, etc.
>
>Some of the Tek schematics I've seen, indicate that certain resistors
>were selected on a per-device basis... in effect, per-oscilloscope
>trim parts.
Back then, the industry was younger and precision was a little less in
focus. So Tek would have had a LOT of custom manufactured parts, and a
lot of what is made custom is responsible for many of the innovations in
manufacturing we currently enjoy.
You MS hating retards are so funny to watch writhe.
Joerg
A 1/4 watt resistor is a "bulk form power resistor"? ROFL!
http://www.vishay.com/docs/28732/vr25.pdf
> Now go find standard values and standard packaging, like SMT that are
> less than 1Mohm. You know... part that we all DO use, not some obscure
> crap (which I already was aware of).
>
> Get back to me when you find even one.
>
You wrote, quote "but you cannot even find 10% resistors in axial", and
I found you one.
>>> 1% is also the most commonly purchased in short qty as well, so you are
>>> going to find 100 pc bags at a cheaper rate than the "cheaper" resistor
>>> because they charge more if they have to pop open a new spool just to
>>> give you your 45 pcs of a resistor nobody else ever orders in popcorn
>>> quantities.
>>
>> Hint: Occasionally it is very educational to open a rock-bottom priced
>> gizmo with a phenolic board in there and take a look what's on that
>> board. You'll be surprised.
>
> Utter nonsense.
Have you ever opened such stuff? Like X-10 modules, toys, remotes, cheap
radio controls? I guess not ...
Joerg
Question: did you even bother to look around? This whole series comes in
10% if you need cheap:
http://www.seielect.com/Catalog/SEI-rpc.pdf
> Get back to me when you find even one.
>
So, there :-)
What's next? That it must be RoHS? Rest assured, they are.
krw
<scor...@thewormholethatemptiesontheothersideoftheuniverse.org>
wrote:
>On Fri, 10 Jul 2009 08:02:32 -0700, Jim Thompson
><To-Email-Use-Th...@My-Web-Site.com> wrote:
>
>>On Fri, 10 Jul 2009 07:54:22 -0700, Joerg <inv...@invalid.invalid>
>>wrote:
>>
>>>life imitates life wrote:
>>>> On Thu, 09 Jul 2009 14:21:40 -0700, Joerg <inv...@invalid.invalid>
>>>> wrote:
>>>>
>>>>> and 5% or 10% really makes a
>>>>> difference in cost.
>>>>
>>>
>>>Please don't quote out of context. This may be why you did not
>>>understand what I wrote.
>>>
>>>
>>[snip]
>>
>>Pay attention, Joerg... you're debating NymNoNuts.
>>
>> ...Jim Thompson
>
>
> Better than acting like a jackass by discussing trolldom with a trollish
>retard like you, jerk.
Been raiding mommy's hamper again DimBulb?
Jim Thompson
Sucking on "rags" ?:-)
life imitates life
wrote:
No, idiot. The one you posted a link to was a 5 watt power resistor.
>
>http://www.vishay.com/docs/28732/vr25.pdf
And, as I stated, it is a High Voltage Resistor.
>> Now go find standard values and standard packaging, like SMT that are
>> less than 1Mohm. You know... part that we all DO use, not some obscure
>> crap (which I already was aware of).
>>
>> Get back to me when you find even one.
>You wrote, quote "but you cannot even find 10% resistors in axial", and
>I found you one.
You did not read what I wrote. These are not standard, everyday parts,
they are purpose specific.
>>>> 1% is also the most commonly purchased in short qty as well, so you are
>>>> going to find 100 pc bags at a cheaper rate than the "cheaper" resistor
>>>> because they charge more if they have to pop open a new spool just to
>>>> give you your 45 pcs of a resistor nobody else ever orders in popcorn
>>>> quantities.
>>>
>>> Hint: Occasionally it is very educational to open a rock-bottom priced
>>> gizmo with a phenolic board in there and take a look what's on that
>>> board. You'll be surprised.
>>
>> Utter nonsense.
>
>Have you ever opened such stuff? Like X-10 modules, toys, remotes, cheap
>radio controls? I guess not ...
I know what it smells like when it burns (the PCB media), so that alone
should tell you enough. That memory originally dates back to the late
sixties. Of course subsequent events indicates further experience.
life imitates life
wrote:
>
>Question: did you even bother to look around?
Answer: I have some experience in electronics manufacturing, including
the use of bulk media (not count, material of construction) and high
voltage types of resistors. I have seen a large array of what can be
expected in resistors. I am sure there are those I have not seen.
I have seen resistors that stop trains.
> This whole series comes in
>10% if you need cheap:
>
>http://www.seielect.com/Catalog/SEI-rpc.pdf
They are not as cheap as you might think. Those are "pulse
withstanding" thick film devices, and I'll bet that they ALL cost more
then the std Vishay stuff in the local catalogues.
>> Get back to me when you find even one.
>So, there :-)
So, maybe you should look closer... and again.
>What's next? That it must be RoHS? Rest assured, they are.
Piss on RoHS, I am exempt. I don' need no stinkin' compliance badges...
JosephKK
wrote:
Sorry about the typo i meant 330k 10%
JosephKK
<alt...@gmail.com> wrote:
>Joerg wrote:
>> Raveninghorde wrote:
>>> On Thu, 09 Jul 2009 21:30:15 GMT, Sergey Kubushin <k...@koi8.net>
>>> wrote:
>>>
>>>> Raveninghorde <raveninghorde@invalid> wrote:
>>>>> Whenever I see app notes I have always noted the strange resistor
>>>>> values used when a value from the E24 range would do just as well.
>>>>>
>>>>> At the moment I am doing a BOM for a design originating in the US.
>>>>> Again I note the liberal use of odd resistor values. For example
>>>>> 332k 1%. What is wrong with 330k? Or 102k 1% instead of 100k?
>>>> 1% resistors are usually made according to E96 range. Making 1% in
>>>> E24 doesn't make sense because difference between consequtive
>>>> values is way bigger than 2% (1% down from the bigger value plus 1%
>>>> up from the smaller one) so your E24 1% set is full of holes. Every
>>>> 5% resistor fits somewhere in E24 but most of random values won't
>>>> if you insist on 1%. That means 332K is a _STANDARD_ value for 1%
>>>> resistor when 330K is
>>>> an oddity.
>>>>
>>>>> If the value needs to be 102k not 100k why specify 1%?
>>>> Because it might be 0.5% or 0.1% or something else.
>>>>
>>>>> For production engineering I would always try to use E24 resistors
>>>>> and always try and mimimize the number of different values.
>>>>>
>>>>> Is this just a big company attitude that specifies any old vlaue
>>>>> the calculator comes up with?
>>>> It is not. E24 1% resistor in the BOM is a crime if this value
>>>> doesn't exist in E96. 332K 1% is a stock item while 330K is not.
>>>>
>>>> See e.g. http://www.logwell.com/tech/components/resistor_values.html
>>>>
>>>> ---
>>>> ******************************************************************
>>>> * KSI@home KOI8 Net < > The impossible we do immediately. *
>>>> * Las Vegas NV, USA < > Miracles require 24-hour notice. *
>>>> ******************************************************************
>>>
>>> I would say that in the UK 330k 1% is standard and ex-stock, 332k 10%
>>> is non standard and will take weeks to get hold of.
>>
>>
>> Ahm, reality check, 330K/1%:
>>
>> http://uk.farnell.com/jsp/search/browse.jsp?N=500006+1000291+372811+294896&Ntk=gensearch_001&Ntt=resistor&Ntx=&No=0&getResults=true&appliedparametrics=true&locale=en_UK&prevNValues=500006+1000291&originalQueryURL=http%3A%2F%2Fuk.farnell.com%2Fjsp%2Fsearch%2Fbrowse.jsp%3FN%3D500006%2B1000291%26Ntk%3Dgensearch_001%26Ntt%3Dresistor%26Ntx%3D%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Den_UK
>>
>> Exactly one through-hole type and one 0603 size. No 0805. I wouldn't
>> exactly call that "popular". Both frigging expensive, my clients would
>> have me flogged if I squandered the BOM budget that way.
>
>Ah, no actually, you obviously checked the wrong box!
>For 330K 1% there are only two as you say with "1%", but 61 items under
>"+/-1%" (typical sorting by parameter trap on these websites):
>http://uk.farnell.com/jsp/search/browse.jsp?N=500006+1000291+294896+570259&Ntk=gensearch_001&Ntt=resistor&Ntx=&No=0&getResults=true&appliedparametrics=true&locale=en_UK&prevNValues=500006+1000291+294896&originalQueryURL=http%3A%2F%2Fuk.farnell.com%2Fjsp%2Fsearch%2Fbrowse.jsp%3FN%3D500006%2B1000291%26Ntk%3Dgensearch_001%26Ntt%3Dresistor%26Ntx%3D%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Den_UK
>
>11 x 0805, 10 x 0603, 5 x 0402 etc
>
>E12 values in 1% are as common as mud, everyone uses them, mostly due to old
>habits as everyone has the E12 range drilled into their head.
>
>Dave.
Alas, i design to E24 by default. But back when i was starting i
found the premium for E24 parts to be worthwhile. The habit remains.
JosephKK
<past...@thebarattheendoftheuniverse.org> wrote:
>On Thu, 09 Jul 2009 23:03:41 +0100, Raveninghorde <raveninghorde@invalid>
>wrote:
>
>>I would say that in the UK 330k 1% is standard and ex-stock, 332k 10%
>>is non standard and will take weeks to get hold of.
>
> He did not say 332k 10% There is no such thing.
>
> THREE significant digits. THINK.
That is part of the point i was making.
JosephKK
<tmor...@charter.net> wrote:
>"Baron" <baron....@linuxmaniac.nospam.net> wrote in message
>news:h384pf$bve$2...@news.eternal-september.org...
>> I smell Mickysoft tactics !
>
>Tektronix has done that forever. They have internal part numbers for
>transistors, diodes, resistors, etc. At least they list equivalents where
>possible though (e.g., 2N3904).
>
>I suppose Tektronix is the electronic Microsoft: dominated the quality
>market for a while, then sold out to crummy equipment and products? ;-)
>
>Tim
Naw. Like all amerkan electronics vendors, manufacturing driven
offshore more an more until only corporate offices are left.
Raveninghorde
wrote:
>Raveninghorde wrote:
>> On Thu, 09 Jul 2009 17:50:10 -0700, life imitates life
>> <past...@thebarattheendoftheuniverse.org> wrote:
>>
>>> On Thu, 09 Jul 2009 18:33:46 +0100, Raveninghorde <raveninghorde@invalid>
>>> wrote:
>>>
>>>> Is this just a big company attitude that specifies any old vlaue the
>>>> calculator comes up with?
>>> No. The values have a specific purpose.
>>
>> Yeah, low voltage cut off point for a battery. 1.05V or 0.95V per cell
>> wouldn't make any difference.
>>
>>> You are doing a layout, or you are actually claiming to have
>>> electronics educational background?
>>
>> Left Uni in 1975 and spent my early years at STC working on high rel
>> amplifiers to pop at the bottom of the ocean for telephone systems
>> such as TAT-7. I've run my own electronics company since 79.
>>
>
>TAT-7 sounds like an interesting project, good old coax. Are you doing a
>lot of fiber-optics stuff nowadays?
>
I left that world behind when I left STC. I never got involved with
fibre though STC were working on it.
The high rel requirement led to conservative design approaches. PCBs
were only just being introduced in 1976, everything before then was
made on custom tag boards with tags mounted on perspex. The fear was
that chemicals could leach out of the pcbs over 25 years in a sealed
environment and lead to corrosion and failure. Even the resistors were
unmarked so that the paint dyes could not leach out.
>
>>> You should know why the values are what they are. Think decades.
>>
>> I prefer to think production. Too many different values is a
>> nuiscence. If I had designed it and need 332k I wold have used 330k
>> and 2k in series, standard values already in the system.
>
>
>I would flag that in a design review. 330K is not part of the E96
>series, 332K is.
Looking at the responses it is clear that E96 resistors are considered
standard in the US. In my experience that is not the case here in the
UK.
krw
<excret...@invalid.invalid> wrote:
>On Thu, 09 Jul 2009 11:46:53 -0700, Joel Koltner wrote:
>
>> If you're completely confident your assembly guys won't inadvertently
>> subsitute 5% resistors on you when you mean 1%
>
>They wouldn't be *my* assembly guys very long, if they did.
Does anyone's "assembly guy" stuff 1K 1% resistors, rather than
P/N 1234567? Why does the "assembly guy" even care if it's a
resistor?
Joerg
Quote from my link "0.25 Watt (1/4 Watt)"
What in that quote is it that you don't understand?
> And, as I stated, it is a High Voltage Resistor.
>
I have given you another example because it seems you haven't looked
around. From Stackpole, 10% resistors that I have designed in.
>>> Now go find standard values and standard packaging, like SMT that are
>>> less than 1Mohm. You know... part that we all DO use, not some obscure
>>> crap (which I already was aware of).
>>>
>>> Get back to me when you find even one.
>
>> You wrote, quote "but you cannot even find 10% resistors in axial", and
>> I found you one.
>
> You did not read what I wrote. These are not standard, everyday parts,
> they are purpose specific.
>
The Stackpole parts aren't everyday parts? And yeah, those 10% resistors
are purpose-specific like most everything else in life. Their purpose is
to shave off cost.
>>>>> 1% is also the most commonly purchased in short qty as well, so you are
>>>>> going to find 100 pc bags at a cheaper rate than the "cheaper" resistor
>>>>> because they charge more if they have to pop open a new spool just to
>>>>> give you your 45 pcs of a resistor nobody else ever orders in popcorn
>>>>> quantities.
>>>> Hint: Occasionally it is very educational to open a rock-bottom priced
>>>> gizmo with a phenolic board in there and take a look what's on that
>>>> board. You'll be surprised.
>>> Utter nonsense.
>> Have you ever opened such stuff? Like X-10 modules, toys, remotes, cheap
>> radio controls? I guess not ...
>
> I know what it smells like when it burns (the PCB media), so that alone
> should tell you enough. That memory originally dates back to the late
> sixties. Of course subsequent events indicates further experience.
Then you have probably never designed very cost-critical stuff. I have,
a lot.
Joerg
> On Fri, 10 Jul 2009 18:00:04 -0700, Joerg <inv...@invalid.invalid>
> wrote:
>
>> Question: did you even bother to look around?
>
>
> Answer: I have some experience in electronics manufacturing, including
> the use of bulk media (not count, material of construction) and high
> voltage types of resistors. I have seen a large array of what can be
> expected in resistors. I am sure there are those I have not seen.
> I have seen resistors that stop trains.
>
I am designing electronics for a living, for over 20 years. Oh, and
during a summer job between my time at the military and start of
university I actually built resistors that stop trains. Brazilian
freight trains, to be exact.
>> This whole series comes in
>> 10% if you need cheap:
>>
>> http://www.seielect.com/Catalog/SEI-rpc.pdf
>
> They are not as cheap as you might think. Those are "pulse
> withstanding" thick film devices, and I'll bet that they ALL cost more
> then the std Vishay stuff in the local catalogues.
>
Carbon resistors are cheap, in China. That plus Malaysia and a few other
countries is where all low-cost electroncis get produced. The trick is
this: You produced resistors with the least amount of process control
and preferably no trimming.
You cannot obtain much info about that from US sources. Datasheets like
the one I showed you, yes, but not Chinese pricing.
>>> Get back to me when you find even one.
>
>> So, there :-)
>
> So, maybe you should look closer... and again.
>
I have, starting around 1994 or so. That was the first time a client
came back to me with this request after I finished a design: "Our
Chinese contract manufacturer is asking which of those 5% resistors we
can ease off to 10% or more. Can you please identify those? Datasheet
comes via fax." (This was the day where not all companies had scanners).
My billed time for this effort was 1/4 hour. The cost savings were IIRC
around 5c per unit, times 50000/year, times 15 years, and counting (it's
still in production). That kind of ROI is stunning. Yet none of this
seems to be taught at universities or anywhere else and most people
don't bother to educate themselves about it, probably because it's
perceived as boring.
Someone who has ever designed with a team in Asia (I have) knows the
drill. They had reams of computer paper hung on hallway walls, updated
about weekly, with fresh commodity pricing of electronic parts. And yes,
all the way down to the lowly resistors and diodes. This wall is what
drove the design process, not elegance or whatever.
>> What's next? That it must be RoHS? Rest assured, they are.
>
> Piss on RoHS, I am exempt. I don' need no stinkin' compliance badges...
Same for most of my design. But not for all of them.
Joerg
> On Thu, 09 Jul 2009 14:21:40 -0700, Joerg wrote:
>
>> Best is if the assembly guys get released part numbers and are never
>> allowed to switch types without at least a deviation signed by
>> engineering.
>
> That's the way I've always done it.
>
It's the only way that works. One client's contract mfg violated this,
once, and promptly hit a brick wall. An expensive one, had to trash
thousands of units. A "more economical" electrolytic had x times the
leakage and they didn't notice that it was in a timing circuit ...
Joerg
[...]
>> E12 values in 1% are as common as mud, everyone uses them, mostly due to old
>> habits as everyone has the E12 range drilled into their head.
>>
>> Dave.
>
> Alas, i design to E24 by default. But back when i was starting i
> found the premium for E24 parts to be worthwhile. The habit remains.
Go to places like Shenzen and design consumer stuff, then you'll be back
to E12. But the 10% variety ;-)
Joerg
They didn't have PCBs before 1976? Wow. Phenolic was quite common then
and well known. For hi-rel stuff I really liked alumina. Much better
than perspex posts and so on. You could seal the whole thing, and we
usually did.
>
>>>> You should know why the values are what they are. Think decades.
>>> I prefer to think production. Too many different values is a
>>> nuiscence. If I had designed it and need 332k I wold have used 330k
>>> and 2k in series, standard values already in the system.
>>
>> I would flag that in a design review. 330K is not part of the E96
>> series, 332K is.
>
> Looking at the responses it is clear that E96 resistors are considered
> standard in the US. In my experience that is not the case here in the
> UK.
E96 is standard here. But only for prototyping and for gear where cost
doesn't matter, or where engineers think it doesn't matter. It always
amazes me when I see a circuit from engineers who aren't great cost
thinkers and then, after re-designing it, cost drops hugely.
Archimedes' Lever
wrote:
> "Our
>Chinese contract manufacturer is asking which of those 5% resistors we
>can ease off to 10% or more.
What a bunch of retards.
Sorry, I do not build cheap chinese crap, so I do not need to deal with
a customer that wants to dictate stupid part purchases to pare a penny
off his rip-off priced piece of shit product.
Contract manufacturers are supposed to build to the print (ours did).
If the retards were asking me if they could switch to other values, the
only other value I'd be switching to is a different contract
manufacturer.
Archimedes' Lever
wrote:
>. That kind of ROI is stunning. Yet none of this
>seems to be taught at universities or anywhere else and most people
>don't bother to educate themselves about it, probably because it's
>perceived as boring.
I know how to economize large volume production. I did not need to
have it taught in school.
I perceive that you thinking the rest of the world doesn't have your
grasp of the industry is pretty fucking boring. Nothing stunning about
that.
Archimedes' Lever
wrote:
>Someone who has ever designed with a team in Asia (I have) knows the
>drill.
Not all makers are turnkey that way. Some MUST and do make what was
designed.
> They had reams of computer paper hung on hallway walls, updated
>about weekly, with fresh commodity pricing of electronic parts.
Good for them.
> And yes,
>all the way down to the lowly resistors and diodes.
In the HV power supply industry, the maker builds what we design and
ONLY what we design. We do not need a batch made one way one month, and
then the next batch having entirely different operating characteristics
because some dope decided to make some substitutions.
If we want 104 C caps, that's what we got. If we wanted a particular
brand due to ESR or 'whatever', that is what we want. We do not need
some chump fuck trying to cut HIS costs compromising the quality of OUR
design. So NO, there will be NO substitution, including resistors and
diodes.
> This wall is what
>drove the design process, not elegance or whatever.
Elegance or whatever has nothing to do with it.
Joerg
It does help if assembly folks know what part is what kind. For
temperature profiles and such. The guys rigging the machines don't need
to know as long as they follow proper ESD procedure.
krw
wrote:
>krw wrote:
>> On Sat, 11 Jul 2009 06:40:45 -0700, Fred Abse
>> <excret...@invalid.invalid> wrote:
>>
>>> On Thu, 09 Jul 2009 11:46:53 -0700, Joel Koltner wrote:
>>>
>>>> If you're completely confident your assembly guys won't inadvertently
>>>> subsitute 5% resistors on you when you mean 1%
>>> They wouldn't be *my* assembly guys very long, if they did.
>>
>> Does anyone's "assembly guy" stuff 1K 1% resistors, rather than
>> P/N 1234567? Why does the "assembly guy" even care if it's a
>> resistor?
>>
>
>It does help if assembly folks know what part is what kind. For
>temperature profiles and such. The guys rigging the machines don't need
>to know as long as they follow proper ESD procedure.
Our "assembly guys" (mostly women, actually) know what process to use
on which products and how to profile them. They have no need to know
what's on the boards, other than inventory numbers. The "assembly
guy" doesn't decide which profile to use. The people doing rework
(sometimes the same people) need to know a little more, perhaps.
Joerg
Well, I meant the personnel at the assembler, not just the workers on
the floor. The foremen and similar folks do need to know IMHO. I would
not advice a client to use a shop where that wasn't the case.
krw
wrote:
Ah, you're including the "manufacturing engineering" people in the
"assembly guys" bucket. I was restricting the group to just those who
push the buttons and load the pick-n-place machines.
Joerg
Not always real engineering. But it does help if the line lead or at
least the foreman knows a thing or two about this stuff. Older ones can
be more knowledgeable than engineers assume. I was once called to a
serious production problem, nearly all boards failed final test. Asked
their engineers whether they had a sit-down with production people.
"Uhm, no, why?". So I had that sit-down. Problem looked like board
warpage. The foreman and I quickly figured out what could be done, for
lunch we headed to a place where there was a large hardware store.
Bought some lumber there, made a few "pre-stretch" frames, sent some
boards through -> all passed.
Jim Thompson
wrote:
Sometimes pisses managers off, but I often go around the manager and
talk to the "down-stream" people to sort out what a chip design
_really_ needs to do.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine Sometimes I even put it in the food
krw
wrote:
Warpage? Pre-stretch? Must be some warped boards to cause failures.
We have some fairly large boards (half-panel) with a lot of heavy
stuff (audio transformers) on them and haven't had too much trouble
with warpage. Certainly no big fallout in assembly.
Joerg
Best place for that chat is often the local tavern after dinner.
Joerg
> On Sun, 12 Jul 2009 09:16:10 -0700, Joerg <inv...@invalid.invalid>
> wrote:
>
[...]
>> Not always real engineering. But it does help if the line lead or at
>> least the foreman knows a thing or two about this stuff. Older ones can
>> be more knowledgeable than engineers assume. I was once called to a
>> serious production problem, nearly all boards failed final test. Asked
>> their engineers whether they had a sit-down with production people.
>> "Uhm, no, why?". So I had that sit-down. Problem looked like board
>> warpage. The foreman and I quickly figured out what could be done, for
>> lunch we headed to a place where there was a large hardware store.
>> Bought some lumber there, made a few "pre-stretch" frames, sent some
>> boards through -> all passed.
>
> Warpage? Pre-stretch? Must be some warped boards to cause failures.
> We have some fairly large boards (half-panel) with a lot of heavy
> stuff (audio transformers) on them and haven't had too much trouble
> with warpage. Certainly no big fallout in assembly.
>
This was a design with tons of RF challenges, there was no way to keep
the copper areas even remotely symmetrical to center. Buried
impedance-controlled traces, umpteen channels, dense as heck, size of an
oven pan, early days of SMT manufacturing and this was all SMT. Oh, and
double-sided.
Joel Koltner
news:nrhh551bsr2k9k735...@4ax.com...
> Sorry, I do not build cheap chinese crap
If the cheap Chinese "crap" is just as good as what you prefer to build (e.g.,
the Chiense stuff has various 10% resistors whereas yours are all 5%), why
not?
Would it change your mind if you were a stockholder and could garner the
company couple a couple million bucks extra each year by going through the
designs and making sure nothing was specified any more tightly than it
actually had to be?
You can bet that Apple, who has everything built in China these days, to very
high specs, is keeping a close watch on exactly how much it costs to build an
iPhone, an iMac, etc... they want to keep their profit margins up! :-)
> Contract manufacturers are supposed to build to the print (ours did).
I would welcome a contract manufacturer who mentioned that they had sources
for cheaper parts if looser tolerances were OK, and if I wanted to they'd be
happy to hook me up.
---Joel
Joel Koltner
news:pan.2009.07.11....@invalid.invalid...
> On Thu, 09 Jul 2009 11:46:53 -0700, Joel Koltner wrote:
>> If you're completely confident your assembly guys won't inadvertently
>> subsitute 5% resistors on you when you mean 1%
> They wouldn't be *my* assembly guys very long, if they did.
I'd give a guy at least one or two strikes on that before showing him the
door, as I'm willing to believe he really was trying to help and didn't
realize the potential pitfall (hence, "inadvertent").
While there are people out there who just don't ever seem to "get it" -- and
their efforts to "help" unfortunately more often than not create problems --
in general my experience is that people who'll at least take a bit of
initiative and *try* to fix a problem (even if *on occasion* they unwittingly
create a bigger problem in the process) are more valuable than those who are
almost robotic and just immediately give up and wait for someone else to come
and tell them what to do the moment they encounter anything that deviates even
the slightest from their prescribed procedure.
You do need people who are circumspect, of course: If a guy is trying to get
some old VW Bug running, by all means, using balling wire and chewing gum and
anything else that might help... but if a guy is trying to get the GE90-115B
jet engine on a Boeing 777 running, it's an entirely different matter.
As engineers we have a responsibility to help assembly people make as few
mistakes as possible. This includes obvious stuff like clear (and correct)
labeling/assembly documentation, but also things like using polarized
connectors (unless you just don't have the budget for it), not putting two
mechanically-identical-but-electrically-vastly-different connectors side by
side (particularly if mis-plugging said connectors blows something up), etc.
---Joel
Rich Grise
> "Tim Williams" <tmor...@charter.net> wrote in message
> news:3JN5m.22$Vg7...@newsfe06.iad...
>> I suppose Tektronix is the electronic Microsoft: dominated the quality
>> market for a while, then sold out to crummy equipment and products? ;-)
>
>
> Now it's "Enabling innovation."
>
> Hmm, OK, but I really think the old one was a stronger statement...
>
> Anyone have a list of company mottos over the years? I would imagine Tek had
> more than the two I've listed here, HP must have had a bunch, etc...
No, but I remember some stuff like that, like:
"See the USA, in your Chevrolet"
"A silly millimeter longer" - Chesterfield 101's
"The seven-minute cigarette" - Pall Mall Gold 100's
And who could forget Burma Shave? ;-)
Cheers!
Rich
Joerg
> "Archimedes' Lever" <OneBi...@InfiniteSeries.Org> wrote in message
> news:nrhh551bsr2k9k735...@4ax.com...
>> Sorry, I do not build cheap chinese crap
>
> If the cheap Chinese "crap" is just as good as what you prefer to build (e.g.,
> the Chiense stuff has various 10% resistors whereas yours are all 5%), why
> not?
>
Yeah, the attitude of some folks that stuff from China is always crap
has brought down whole companies. I will never understand it. After we
did a major cost reduction effort at an ultrasound company (without
compromising quality at all) one of our two main competitors threw in
the towel for our market. That was Hewlett-Packard, no less.
This reminds me of major ROFL episodes among the big three in Detroit
when the VW Beetle was presented. Nobody is laughing there anymore ...
> Would it change your mind if you were a stockholder and could garner the
> company couple a couple million bucks extra each year by going through the
> designs and making sure nothing was specified any more tightly than it
> actually had to be?
>
> You can bet that Apple, who has everything built in China these days, to very
> high specs, is keeping a close watch on exactly how much it costs to build an
> iPhone, an iMac, etc... they want to keep their profit margins up! :-)
>
>> Contract manufacturers are supposed to build to the print (ours did).
>
> I would welcome a contract manufacturer who mentioned that they had sources
> for cheaper parts if looser tolerances were OK, and if I wanted to they'd be
> happy to hook me up.
>
Oh yes! There is no purpose in having 1% or 5% pull-up resistors for
push-button inputs or digital lines. It's like wearing sun screen under
a swim suit. I have spec'd in as loose as 20%. Because it didn't matter.
The most coarse was -10% to -35% in hybrid production, meaning that we
simply skipped the laser trim step for many resistors that were
deposited on the alumina substrate. That shaved off some pennies. At
tens of thousands per year that kind of savings really matters and is
worth the several extra engineering hours that had to be put in (which
we did).
Joerg
Best happened yesterday. Us walking three dogs, two neighbor dogs escape
and barge out. Situation gets under control, neighbor says he is sorry
and just watching one of the dogs for a friend. "Hey, we've never seen
that one. What breed is it?" ... "Ah, ahm, well, a Budweiser dog".
http://upload.wikimedia.org/wikipedia/en/2/23/Spuds_mackenzie.jpg
krw
wrote:
Sure there is. It reduces P/N count, saving inventory problems and
possibly a second (perhaps impossible) pass at the pick-n-place
machine.
>The most coarse was -10% to -35% in hybrid production, meaning that we
>simply skipped the laser trim step for many resistors that were
>deposited on the alumina substrate. That shaved off some pennies. At
>tens of thousands per year that kind of savings really matters and is
>worth the several extra engineering hours that had to be put in (which
>we did).
Different issues. Saving steps isn't the same as adding parts.
krw
Joerg
Thou shalt not use a machine that's close to being tapped out in terms
of slots ;-)
But seriously, this problem was fixed with two measures:
a. All 100K resistors became 10%.
b. The contract mfg supplies stock and they've got no problem whatsoever
with inventory because they make tons of other stuff. Otherwise they
wouldn't have asked us.
>> The most coarse was -10% to -35% in hybrid production, meaning that we
>> simply skipped the laser trim step for many resistors that were
>> deposited on the alumina substrate. That shaved off some pennies. At
>> tens of thousands per year that kind of savings really matters and is
>> worth the several extra engineering hours that had to be put in (which
>> we did).
>
> Different issues. Saving steps isn't the same as adding parts.
No parts were added, they were changed in spec and ECO'd part numbers.
krw
wrote:
In this economy, thou shalt use what thou has. Thou shalt not whine
for new toys. ;-)
>But seriously, this problem was fixed with two measures:
>
>a. All 100K resistors became 10%.
>
>b. The contract mfg supplies stock and they've got no problem whatsoever
>with inventory because they make tons of other stuff. Otherwise they
>wouldn't have asked us.
We don't use contract manufacturers. Inventory control isn't free.
OTOH, if the owner was really interested in saving money, he'd insist
that IT link the purchasing/inventory database and the
engineering/production databases. As it is, I only have a hint at
what _some_ parts cost, and I've caught purchasing buying parts for
4-5x what they should be paying.
>>> The most coarse was -10% to -35% in hybrid production, meaning that we
>>> simply skipped the laser trim step for many resistors that were
>>> deposited on the alumina substrate. That shaved off some pennies. At
>>> tens of thousands per year that kind of savings really matters and is
>>> worth the several extra engineering hours that had to be put in (which
>>> we did).
>>
>> Different issues. Saving steps isn't the same as adding parts.
>
>
>No parts were added, they were changed in spec and ECO'd part numbers.
Skipping a trim step <> adding a part number.
Joerg
> On Mon, 13 Jul 2009 15:57:31 -0700, Joerg <inv...@invalid.invalid>
> wrote:
>
>> krw wrote:
>>> On Mon, 13 Jul 2009 12:09:49 -0700, Joerg <inv...@invalid.invalid>
>>> wrote:
>>>
[...]
>> But seriously, this problem was fixed with two measures:
>>
>> a. All 100K resistors became 10%.
>>
>> b. The contract mfg supplies stock and they've got no problem whatsoever
>> with inventory because they make tons of other stuff. Otherwise they
>> wouldn't have asked us.
>
> We don't use contract manufacturers. Inventory control isn't free.
> OTOH, if the owner was really interested in saving money, he'd insist
> that IT link the purchasing/inventory database and the
> engineering/production databases. ...
In larger companies that's linked. In the one where I took over a
division it wasn't at that time but we made darn sure this was done, and
soon.
> ... As it is, I only have a hint at
> what _some_ parts cost, and I've caught purchasing buying parts for
> 4-5x what they should be paying.
>
Exactly that is one reason for using contract manufacturers. They never
pay 4-5x of what they should be paying. More like 0.8-0.9x because with
their qties they have so much more negotiating power.
>>>> The most coarse was -10% to -35% in hybrid production, meaning that we
>>>> simply skipped the laser trim step for many resistors that were
>>>> deposited on the alumina substrate. That shaved off some pennies. At
>>>> tens of thousands per year that kind of savings really matters and is
>>>> worth the several extra engineering hours that had to be put in (which
>>>> we did).
>>> Different issues. Saving steps isn't the same as adding parts.
>>
>> No parts were added, they were changed in spec and ECO'd part numbers.
>
> Skipping a trim step <> adding a part number.
Got to streamline that process. At Endosonics we "electronicized" the
ECO process. No more walking a stack of papers to the next signing
person. You could have an urgent ECO signed off in under 15 minutes.
Anyhow, the first time I eased off resistor tolerances for a client it
saved them 5c/unit. Doesn't sound like much. I billed 0.25 hours for my
time for this task because that's all it took. Then they began to
produce around 50k units/year, looks like this product could make it to
the 20 year anniversary. For the cost savings to date you could buy a
nicely equipped Cadillac (the owner did ...). Unfortunately this product
has now survived the owner :-(
Archimedes' Lever
<zapwireD...@yahoo.com> wrote:
>If the cheap Chinese "crap" is just as good as what you prefer to build (e.g.,
>the Chiense stuff has various 10% resistors whereas yours are all 5%), why
>not?
Sorry, but even between different makers of metal film 1% resistors,
there are differences in operation.
When you have 1mV ripple figure on a 4kV x-ray supply, changing a
resistor maker can change that figure in a bad way usually. If what you
sell is a sub 1mV PARD figure for that supply, and you have some lame
contract maker build 100 of them for you, unless he knows how to keep to
the BOM, you are going to get 100 different power supplies, and an
unhappy customer.
Joel Koltner
> Sorry, but even between different makers of metal film 1% resistors,
> there are differences in operation.
Sure, my point was that it's usually worthwhile to spend the time to consider
which parts can be substituted (or have their tolerances loosened) and which
can't. Also that it's preferable to work with a CM who'll be sure to mention
all the tricks *they* know that *might* allow you to reduce the costs of your
design.
---Joel
Archimedes' Lever
<zapwireD...@yahoo.com> wrote:
>Would it change your mind if you were a stockholder and could garner the
>company couple a couple million bucks extra each year by going through the
>designs and making sure nothing was specified any more tightly than it
>actually had to be?
If I were doing multiple M counts of a given build, *I* would economize
the design, not the contract builder. They are nothing more than
assemblers. My contract builds usually involve MY purchased parts. Were
I to do a turnkey build, I would specify in the quote request, everything
in the BOM that had to remain the same, right down to the maker, and
everything which can be his turnkey part. He would not, however, get to
reduce tolerances on a part. It is in no way up to the contract
assembler house to make any design change decisions based on his guesses
about the design or function of ANY given section of ANY given circuit
design.
Archimedes' Lever
<zapwireD...@yahoo.com> wrote:
>You can bet that Apple, who has everything built in China these days, to very
>high specs, is keeping a close watch on exactly how much it costs to build an
>iPhone, an iMac, etc... they want to keep their profit margins up! :-)
Bull. You can bet that the China builder is building the EXACT product
Apple specs out, and Apple buys the entire facility, and stocks it with
their part, and NOBODY is economizing the design of ANYTHING.
Did you honestly believe that Apple goes contract builder shopping in
China, and picks someone that is building other things as well? I do
not. I think they went over there and BOUGHT lock-stock-and-barrel
everything. They OWN contract builders in China.
The mere fact that they are building there instead of here now, is
enough margin gain alone. They do not need to piss around compromising
their design to save one penny over a million capacitors. It is far
cheaper to install the BOM, and save the admin fees of some dope spending
a years salary to save $10k.
You can bet that with the volumes that Aplle sells, they are already
getting all their electronic parts cheaper than you EVER did at ANY time
in your ENTIRE LIFE. So they are ALREADY economized out the yin yang at
the front end. There is no ass end economizing like that which you are
familiar with ever needed.
AwlSome Auger
wrote:
>On Fri, 10 Jul 2009 13:52:04 -0700, Joel Koltner wrote:
The White Tornado
Andy Rooney would love it!
Joel Koltner
> On Mon, 13 Jul 2009 10:39:00 -0700, "Joel Koltner"
> <zapwireD...@yahoo.com> wrote:
>>You can bet that Apple, who has everything built in China these days, to
>>very
>>high specs, is keeping a close watch on exactly how much it costs to build
>>an
>>iPhone, an iMac, etc... they want to keep their profit margins up! :-)
> Bull. You can bet that the China builder is building the EXACT product
> Apple specs out, and Apple buys the entire facility, and stocks it with
> their part, and NOBODY is economizing the design of ANYTHING.
I said that it was *Apple* who's doing whatever they can to keep their costs
down; no one here was suggesting a (good) CM would run off and start making
changes to a design without getting sign-off from their customer.
> Did you honestly believe that Apple goes contract builder shopping in
> China, and picks someone that is building other things as well? I do
> not. I think they went over there and BOUGHT lock-stock-and-barrel
> everything. They OWN contract builders in China.
I don't really know, but that is a very interesting question. I suppose they
do have enough volume to do so if they wanted to.
> The mere fact that they are building there instead of here now, is
> enough margin gain alone. They do not need to piss around compromising
> their design to save one penny over a million capacitors.
The big savings are in the overall architecture, certainly -- I expect you've
read Joerg's stories where he's been able to replace, e.g., an entire DSP
(maybe $10?) with under a buck worth of discrete parts. That's significant.
Heck, saving just ten cents on something you're building a million of per year
is enough to fully pay a U.S. engineer's salary.
---Joel
Joerg
> "Archimedes' Lever" <OneBi...@InfiniteSeries.Org> wrote in message
> news:4imn55h4dsi0d900b...@4ax.com...
[...]
>> The mere fact that they are building there instead of here now, is
>> enough margin gain alone. They do not need to piss around compromising
>> their design to save one penny over a million capacitors.
>
> The big savings are in the overall architecture, certainly -- I expect you've
> read Joerg's stories where he's been able to replace, e.g., an entire DSP
> (maybe $10?) with under a buck worth of discrete parts. That's significant.
Plus eliminated something like $150-200 worth of programmable digital
delay lines per system. Oh, was that sales rep pissed.
> Heck, saving just ten cents on something you're building a million of per year
> is enough to fully pay a U.S. engineer's salary.
>
1/4 hour of my billed time (to ease some resistor tolerances to 10%)
bought the boss of a client savings worth a nice Cadillac over 15
production years. He took me to dinner in it, very nice ride :-)
Archimedes' Lever
<zapwireD...@yahoo.com> wrote:
>Sure, my point was that it's usually worthwhile to spend the time to consider
>which parts can be substituted (or have their tolerances loosened)
Well, we ALL already knew that. The thing is that you don't go letting
your CM dictate such things to you.
Joerg
The talk was never about the contract manufacturer dictating anything.
They don't, or they lose the contract. What they did in my cases was
suggesting something to be changed. That is most welcome feedback. Then
it was up to my client who then left it up to me to figure out whether
that is technically feasible. Sometimes resulting in rather remarkable
cost savings.
Of course all this usually doesn't make much sense if you only produce
1000/year. But then you probably would not contract out anyhow.
Archimedes' Lever
<zapwireD...@yahoo.com> wrote:
> Also that it's preferable to work with a CM who'll be sure to mention
>all the tricks *they* know that *might* allow you to reduce the costs of your
>design.
I am perfectly capable of doing a thorough "DFM" cycle. Cost reduction
on parts came long before that.
Perhaps not with today's young engineers, but I come from a time when
we knew more than any CM we ever contracted to build one of our designs.
That is certainly true where I am now, where every single part is
verified, and no changes are even allowed. Tempest certs are tough, even
for a simple USB device, for example.
All of our CMs build what we spec. Some of our kits have thousands of
dollars worth of parts left over that never get used, and go past their
usable service life for soldering before they could even get shoved back
through the system. The admin to examine it alone would cost thousands.
If I could have all the expired popcorn that is around here, I could
build several motherboards worth of assembly (like 50k + parts easily).
All perfect parts, aside from the exp date. Hand solder is fine though.
Primo parts. I wish I could have them all.
Joerg
> On Mon, 13 Jul 2009 18:06:06 -0700, "Joel Koltner"
> <zapwireD...@yahoo.com> wrote:
>
>> Also that it's preferable to work with a CM who'll be sure to mention
>> all the tricks *they* know that *might* allow you to reduce the costs of your
>> design.
>
> I am perfectly capable of doing a thorough "DFM" cycle. Cost reduction
> on parts came long before that.
>
> Perhaps not with today's young engineers, but I come from a time when
> we knew more than any CM we ever contracted to build one of our designs.
>
> That is certainly true where I am now, where every single part is
> verified, and no changes are even allowed. Tempest certs are tough, even
> for a simple USB device, for example.
>
> All of our CMs build what we spec. Some of our kits have thousands of
> dollars worth of parts left over that never get used, and go past their
> usable service life for soldering before they could even get shoved back
> through the system. The admin to examine it alone would cost thousands.
>
Oh man ...
Is that cost finally ending up with the taxpayer? If you had such
left-overs in industry the responsible person would receive an
"invitation" to the CFO's office, the door would be closed and it would
get very loud in there.
This is one reason why I have steered companies away from the old
kitting process pretty much everywhere I worked. It's wasteful.
> If I could have all the expired popcorn that is around here, I could
> build several motherboards worth of assembly (like 50k + parts easily).
> All perfect parts, aside from the exp date. Hand solder is fine though.
> Primo parts. I wish I could have them all.
So what happens with all that. It's chucked?
Rich Grise
>
> As engineers we have a responsibility to help assembly people make as few
> mistakes as possible. This includes obvious stuff like clear (and correct)
> labeling/assembly documentation, but also things like using polarized
> connectors (unless you just don't have the budget for it), not putting two
> mechanically-identical-but-electrically-vastly-different connectors side by
> side (particularly if mis-plugging said connectors blows something up), etc.
>
that we used in development - a dual-port RAM that acted like a ROM in-
circuit.
Somebody told me that the assemblers could build from a schematic. Cool,
I says, I don't have to do it! Unfortunately, I had used the convention
of showing all the bypass caps on the bus, rather than at each chip with
all those damn wires; when I got the board, there were the bypasses, in
a nice neat row, right next to the power bus. It turned out not to be a
problem; it took her about 10 minutes to add a half a dozen caps, so it
was no big deal. I guess the moral is, be more specific. :-)
Cheers!
Rich
Archimedes' Lever
wrote:
>
>This is one reason why I have steered companies away from the old
>kitting process pretty much everywhere I worked. It's wasteful.
>
At our company, stupidity like yours is what is wasteful. a few
hundred, or even a few thousand left over discreet parts is no big deal
when the assemblies are several tens of thousands of dollars as a
finished product. A couple hundred bucks worth of attrition is not even
worth tallying up.
Handling them in such a way as to re-introduce them into the MRP system
would take long enough that many would be expired going in, and therefore
unusable.
Unlike you, we cannot utilize parts that are past their solderability
expiry dates, and ALL parts have them, whether you know it or not.
Archimedes' Lever
wrote:
>
>So what happens with all that. It's chucked?
Ten years from now, when there is no chance that any component could be
used to undermine the nation's security. Yes, even "dumb" components.
Archimedes' Lever
wrote:
>
>Is that cost finally ending up with the taxpayer?
That "cost" as you call it is a savings to the taxpayer. When the parts
ALL have to be ordered to the job, and expiration dates creep up, the
cost to retain tailings on kits and re-introduce them into the system id
far greater than simply ordering what was needed and getting the job
done.
To implement your "cost reduction" CRAP would cost the taxpayer far
more, and in a mission critical application, it could even cost lives.
That is unacceptable.
So shut the fuck up about that which you obviously know absolutely
nothing about. Not everyone uses the same model you have stuck in your
brain.
Joerg
Ah, so the taxpayer does have to eat this. Then it's "easier" to chuck
$50k worth of parts.
Joel Koltner
> Ten years from now, when there is no chance that any component could be
> used to undermine the nation's security. Yes, even "dumb" components.
If you're so worried that a few 0603 resistor values are going to compromise
national security, do all of your CM's employees have "secret" level or higher
clearances?
Raveninghorde
Exactly. Reduced number of different parts saves inventory and reduces
machine time. As I make in the UK this is probably more important
than if I was making in China. Also given that resistors come in reels
of 5000 then if you make 500 using a special value then 4500 are held
in stock until scrapped.