Reply by Edward Hernandez●November 17, 20212021-11-17
The John Doe troll stated the following in message-id
<sdhn7c$pkp$4@dont-email.me>:
> The troll doesn't even know how to format a USENET post...
And the John Doe troll stated the following in message-id
<sg3kr7$qt5$1@dont-email.me>:
> The reason Bozo cannot figure out how to get Google to keep from
> breaking its lines in inappropriate places is because Bozo is
> CLUELESS...
And yet, the clueless John Doe troll has itself posted yet another
incorrectly formatted USENET posting on Wed, 17 Nov 2021 08:18:42 -0000
(UTC) in message-id <sn2dt2$s3e$5@dont-email.me>.
This posting is a public service announcement for any google groups
readers who happen by to point out that the John Doe troll does not even
follow it's own rules that it uses to troll other posters.
1gPN3spxiUqo
Reply by Anthony William Sloman●November 17, 20212021-11-17
On Wednesday, November 17, 2021 at 7:18:48 PM UTC+11, John Doe wrote:
> Anthony William Sloman <bill....@ieee.org> wrote:
> > On Tuesday, November 16, 2021 at 2:48:29 AM UTC+11, jla...@highlandsniptechnology.com wrote:
> >> On Mon, 15 Nov 2021 15:15:25 GMT, Jan Panteltje
> >> <pNaOnSt...@yahoo.com> wrote:
> >>
> >> >On a sunny day (Sun, 14 Nov 2021 14:22:45 -0800) it happened
> >> >jla...@highlandsniptechnology.com wrote in
> >> ><ss23pgp37oil6tqvi...@4ax.com>:
> >> >
> >> >>When I see a schematic full of trimpots, it's a sure bet that the
> >> >>author doesn't understand things.
> >> >
> >> >
> >> >In the older days trimpots were common for opamp offset compensation in
> > many precision circuits.
> >> >Not sure if modern opamps still have offset errors?
> >>
> >> Some have a few uV offset and a few nV/degc drifts.
> >
> > Every last op amp has built-in thermocouples and built-in thermal gradients, There's always a few microvolts of thermocouple potential and it varies with heat dissipation.
> >
> >>But we cal things out in automated test, and save the cal table in flash,
> > so don't need pots. Sometimes we even cal out tempcos, which takes longer but nobody is standing around watching.
> >
> > Which is worth doing, if you are producing in volume. What the Review of Scientific Instruments reports are one-off and short series instrument designs used to solve specific scientific problems.
> >
> >> Turning trimpots to tweak tempcos is for masochists.
> >
> > But writing an elaborate program to do it for you is also time consuming - it's quicker to twiddle a few trimpots by hand if there are only ever going to be a few of them
> >The Review Of Scientific Instruments is full of trimpots. And diffamps.
> > And current mirrors.
> >
> > And John Larkin doesn't seem to like designing them into his own circuits,
> >
> >> >Its the same with variable inductors, radios used to be full of those, n
> > ow everything is done in silicon.rtl-sdr USB stick as example.
> >
> > Not always.
> >
> > https://www.tdk-electronics.tdk.com/inf/80/db/fer/rm_10.pdf
> >
> > Note the screw-in adjuster on page 8. If you really do need to change the inductance of an inductance made with an RM10 core, this is one long-established way of doing it. There are bigger cores and bigger adjusters if you need more inductance, and different core materials if you need higher frequencies.
<snipped the usual irrelevant drivel - John Doe has decided to be a total stalker, horning in on threads that he knows nothing about>
--
Bill Sloman, Sydney
>> That wouldn't fly with me. :-)
>
> Have you tried filling your airbed with helium?
There is an idea!!!
I absolutely LOVE my air mattress.
Wild white horses couldn't drag me back to an ordinary mattress. I'm
bewildered why they aren't universal (except the usual conspiracy theory
about the status quo keeping that from happening). Rolling around is so
easy on an air mattress. Maybe people fall off. Maybe most people are too
heavy. Too many cats (but prior mattresses can be gutted and used as
covers for new mattresses). Who knows. Apparently the reason they are so
comfortable is because air pressure is the same everywhere. Hospitals use
them.
Reply by Jan Panteltje●November 17, 20212021-11-17
On a sunny day (Tue, 16 Nov 2021 23:46:21 +0100) it happened Jeroen Belleman
<jeroen@nospam.please> wrote in <sn1cbt$p8c$1@gioia.aioe.org>:
"the concepts "male" and "female" are essentially social constructions" (Bill Sloman)
"the Mueller investigation was about Trump only because Trump made it so" (Bozo paraphrased)
A non-American America-bashing chronic liar...
--
Anthony William Sloman <bill.sloman@ieee.org> wrote:
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> Subject: Re: juggling parts
> From: Anthony William Sloman <bill.sloman@ieee.org>
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> Xref: reader02.eternal-september.org sci.electronics.design:652598
>
> On Tuesday, November 16, 2021 at 2:48:29 AM UTC+11, jla...@highlandsniptechnology.com wrote:
>> On Mon, 15 Nov 2021 15:15:25 GMT, Jan Panteltje
>> <pNaOnSt...@yahoo.com> wrote:
>>
>> >On a sunny day (Sun, 14 Nov 2021 14:22:45 -0800) it happened
>> >jla...@highlandsniptechnology.com wrote in
>> ><ss23pgp37oil6tqvi...@4ax.com>:
>> >
>> >>When I see a schematic full of trimpots, it's a sure bet that the
>> >>author doesn't understand things.
>> >
>> >
>> >In the older days trimpots were common for opamp offset compensation in
> many precision circuits.
>> >Not sure if modern opamps still have offset errors?
>>
>> Some have a few uV offset and a few nV/degc drifts.
>
> Every last op amp has built-in thermocouples and built-in thermal gradients, There's always a few microvolts of thermocouple potential and it varies with heat dissipation.
>
>>But we cal things out in automated test, and save the cal table in flash,
> so don't need pots. Sometimes we even cal out tempcos, which takes longer but nobody is standing around watching.
>
> Which is worth doing, if you are producing in volume. What the Review of Scientific Instruments reports are one-off and short series instrument designs used to solve specific scientific problems.
>
>> Turning trimpots to tweak tempcos is for masochists.
>
> But writing an elaborate program to do it for you is also time consuming - it's quicker to twiddle a few trimpots by hand if there are only ever going to be a few of them
>
>> >>The Review Of Scientific Instruments is full of trimpots. And diffamps.
> And current mirrors.
>
> And John Larkin doesn't seem to like designing them into his own circuits,
>
>> >Its the same with variable inductors, radios used to be full of those, n
> ow everything is done in silicon.rtl-sdr USB stick as example.
>
> Not always.
>
> https://www.tdk-electronics.tdk.com/inf/80/db/fer/rm_10.pdf
>
> Note the screw-in adjuster on page 8. If you really do need to change the inductance of an inductance made with an RM10 core, this is one long-established way of doing it. There are bigger cores and bigger adjusters if you need more inductance, and different core materialsif you need higher frequencies.
>
> --
> Bill Sloman, Sydney
>
>
Reply by Jan Panteltje●November 17, 20212021-11-17
On a sunny day (Tue, 16 Nov 2021 15:44:40 -0800) it happened John Larkin
<jlarkin@highland_atwork_technology.com> wrote in
<cgg8pglo7s0150p9vsvlb2irc51lcb96cq@4ax.com>:
>Carbon comps have been used as poor-man's cryo temperature sensors.
>They are relatively immune to magnetic fields that trash diode
>sensors.
High value carbon comps were used in many old tube TVs, and the Vitrohm ones were a common source of problems.
Would go high.
But IIRC some low value would go short too after overheating.
Very unreliable stuff.
Reply by Gerhard Hoffmann●November 16, 20212021-11-16
Am 17.11.21 um 00:41 schrieb John Larkin:
...
thick film resistors also create an enormous amount
of 1/f noise when there is DC over them.
Gerhard
Reply by Phil Hobbs●November 16, 20212021-11-16
John Larkin wrote:
> On Tue, 16 Nov 2021 17:29:04 -0500, Phil Hobbs
> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>
>> jlarkin@highlandsniptechnology.com wrote:
>>> On Tue, 16 Nov 2021 11:23:59 -0500, legg <legg@nospam.magma.ca> wrote:
>>>
>>>> On Tue, 16 Nov 2021 07:40:30 -0800, jlarkin@highlandsniptechnology.com
>>>> wrote:
>>>>
>>>>> On Tue, 16 Nov 2021 08:56:07 -0500, legg <legg@nospam.magma.ca> wrote:
>>>>>
>>>>>> On Sun, 14 Nov 2021 10:27:20 -0800, jlarkin@highlandsniptechnology.com
>>>>>> wrote:
>>>>>>
>>>>>> <snip>
>>>>>>>> What I do not get is: you sell expensive things in low quantity and try to save on a trimpot?
>>>>>>>
>>>>>>> Trimpots are expensive and need manual turning. DACs are automated and
>>>>>>> can have cal factors stored in cal tables. I'm using 16-bit DACs and
>>>>>>> there are no 16-bit trimpots.
>>>>>>>
>>>>>>> Some of my customers absolutely forbid trimpots, which I think is
>>>>>>> extreme. Once in a while they make sense. They say that if there's a
>>>>>>> pot, their techs will turn it.
>>>>>>>
>>>>>>
>>>>>> If the tech doesn't have access to the cal table, that DAC's not doing
>>>>>> the work of a trimpot.
>>>>>>
>>>>>> RL
>>>>>
>>>>> It's preventing him from mucking with something he doesn't understand
>>>>> and doesn't have the equipment to calibrate. Besides, some products
>>>>> have a hundred cal factors.
>>>>>
>>>>> If something in a signal chain is broken, twiddling pots will break
>>>>> more things. We rarely use trimpots, and then only to tweak gain in
>>>>> GHz-range amplifiers.
>>>>
>>>> If it's not meant to be adjusted, then sot fixed parts are more a
>>>> suitable analog comparison. A trimpot would be an unjustified
>>>> vulnerability, simply from a reliability and cost standpoint.
>>>>
>>>> I'm finding that that programmable part are increasingly dominant in
>>>> non-repairability situations, so It rankles when the equation is
>>>> made to an impractical analog equivalent.
>>>>
>>>> RL
>>>
>>> We do polynomial calibrations all the time. Try that with trimpots!
>>>
>>>
>>>
>>>
>> Exact used to make an arbitrary waveform generator with about 25 dial
>> pots on the front panel, one per sample point. ;)
>
> And I think they are extinct!
>
Haven't seen a new one in many years, so I assume so.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.nethttp://hobbs-eo.com
Reply by John Larkin●November 16, 20212021-11-16
On Tue, 16 Nov 2021 11:54:51 -0800 (PST), whit3rd <whit3rd@gmail.com>
wrote:
>On Monday, November 15, 2021 at 7:49:48 AM UTC-8, jla...@highlandsniptechnology.com wrote:
>> On Mon, 15 Nov 2021 23:07:34 +1100, Chris Jones
>> <lugn...@spam.yahoo.com> wrote:
>>
>> >On 15/11/2021 16:34, whit3rd wrote:
>
>> >> When mailorder is slow, and you have a triangle file and carbon comp
>> >> resistor in play, it's time to declare armistice or maybe even peace.
>> >>
>> >> Remember, after filing the notch, to use some nail polish for
>> >> sealing that surface... or job it out to a cosmetology shop.
>
>> >Barbarian, using a triangle file, think of the mechanical stress
>> >concentration begging it to snap in half. Use a round chainsaw
>> >sharpening file or round needle file at least! I'd even consider
>> >drilling a few small holes part way through it would be more humane.
>
>> I haven't seen a carbon comp resistor in years.
>
>Lucky you! They were employed as trimmers by none other than
>Seymour Cray, back in the dark ages of RTL, before computers could Spice
>faster than techs could wirewrap.
Carbon comps have been used as poor-man's cryo temperature sensors.
They are relatively immune to magnetic fields that trash diode
sensors.
--
If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon
Reply by John Larkin●November 16, 20212021-11-16
On Tue, 16 Nov 2021 19:07:59 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:
>On 2021-11-16 16:35, jlarkin@highlandsniptechnology.com wrote:
>> On Tue, 16 Nov 2021 22:42:52 +1100, Chris Jones
>> <lugnut808@spam.yahoo.com> wrote:
>>
>>> On 16/11/2021 02:49, jlarkin@highlandsniptechnology.com wrote:
>>>> On Mon, 15 Nov 2021 23:07:34 +1100, Chris Jones
>>>> <lugnut808@spam.yahoo.com> wrote:
>>>>
>>>>> On 15/11/2021 16:34, whit3rd wrote:
>>>>>> On Sunday, November 14, 2021 at 2:14:53 PM UTC-8, TTman wrote:
>>>>>>> On 14/11/2021 18:27, jla...@highlandsniptechnology.com wrote:
>>>>>>
>>>>>>>> I have space on this one for a few more 0603s. It's inefficient to
>>>>>>>> load a reel onto the pick-and-place just for one resistor.
>>>>>>
>>>>>>> Pots are your enemy...
>>>>>>
>>>>>> When mailorder is slow, and you have a triangle file and carbon comp
>>>>>> resistor in play, it's time to declare armistice or maybe even peace.
>>>>>>
>>>>>> Remember, after filing the notch, to use some nail polish for
>>>>>> sealing that surface... or job it out to a cosmetology shop.
>>>>>>
>>>>>
>>>>> Barbarian, using a triangle file, think of the mechanical stress
>>>>> concentration begging it to snap in half. Use a round chainsaw
>>>>> sharpening file or round needle file at least! I'd even consider
>>>>> drilling a few small holes part way through it would be more humane.
>>>>>
>>>>
>>>> I haven't seen a carbon comp resistor in years.
>>>
>>> The only good use I can think of for them is absorbing large pulses of
>>> energy in a very short time, as the heat would be deposited throughout a
>>> larger mass than the mass of a thin or thick film.
>>>
>>
>> AoE X-chapters, p 26, has some great data about exploding various
>> resistors. The carbon comps win for short pulses, below about 1
>> millisecond.
>>
>> I always assumed that 50 ohm cc's were best for high frequency
>> termination, but the cheap carbon film resistors are about as good.
>> Surface-mount thick films are better than either... less lead
>> inductance.
>>
>>
>>
>
>I've tried several low-value resistors for high-frequency matching pads
>and terminations. SMD 1206 resistors tend to be too capacitive, and the
>similar-sized MELFs are too inductive. It's easier to gimmick the MELFs,
>so that's what I tend to choose when it matters.
>
>Jeroen Belleman
Several people make thick-film resistors that drop into a DPAK
footprint. They are good for 5 watts or so if you heatsink the paddle
to a ground plane. They are actually pretty good at sub-nanosecond
speeds.
https://www.dropbox.com/sh/qr1bmnz0calio9j/AACCdLtMt03JhbEv6WtmLEKta?dl=0
Caddock makes some amazing axial resistors that HP used in their
54006A 5 GHz passive probes.
https://www.dropbox.com/s/u9uoowelrfgnt06/Caddock_450.JPG?dl=0
I recently did a signal pickoff:
sig------1K 0603----+----amp---50r-----out
|
20r 0603 || cap
|
gnd
It was horrible. I'll try something else.
--
If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon