AoE x-Chapters - 1x.2 Resistors

[Winfield Hill]

tabbypurr@gmail.com wrote...

On Sunday, 4 August 2019 16:20:24 UTC+1, Winfield Hill wrote:

Here's another AoE x-Chapters DRAFT section to
read and think about. 1x.2 Resistors, takes up
aspects of resistors not discussed in AoE III.
This is a draft, with more to add, figures not
yet placed properly, etc. Comments solicited.

https://www.dropbox.com/s/dli62uyuldr7z5q/1x.2_Resistors_DRAFT.pdf?dl=1

Fig 1x.30: I'd suggest adding construction type to the list printed on the
graph.
Fig 1x.32, lower graph: scales marked -0.5% and -50%!
Fig 1x.37: if you move the B to above the C it would be clearer

"Its failure mode, like the carbon-film CMA, includes
a low-resistance current surge and a fail-short endpoint."

Some readers may misinterpret that as meaning that it shorts permanently. In
fact they can go very low R but recover & resume normal service.

Figure 1x.39 Including social stuff is only going to irk those who don't know
you from Adam and have no interest.

Motor driven panel pots were still in mass production in a minority of consumer
stereos in the 80s.

Fig 1x.43 lacks any scale markings.

p32 'niceties' - I'm not sure those are niceties according to a dictionary.


NT

Thanks, lots of good comments.


--
Thanks,
- Win

 

[Don Kuenz, KB7RPU]

tabbypurr@gmail.com wrote:

<snip>

Figure 1x.39 Including social stuff is only going to irk those who
don't know you from Adam and have no interest.

OTOH, it does add local color reminiscent of Bob Pease to a potentially
dry tome. Although Pease would've probably said something along the
lines of:

John Larkin of Highland Technology wrote a nice explanation of
his pulse-power torture machine in sci.electronics.design ...

This local color also functions as an Easter egg that enables insiders
to feel special, to be "in the know," regardless of how they feel about
Larkin.

Thank you, 73,

--
Don Kuenz KB7RPU
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.

 

[John Larkin]

On Mon, 5 Aug 2019 06:31:27 -0700 (PDT), tabbypurr@gmail.com wrote:

On Sunday, 4 August 2019 16:20:24 UTC+1, Winfield Hill wrote:

Here's another AoE x-Chapters DRAFT section to
read and think about. 1x.2 Resistors, takes up
aspects of resistors not discussed in AoE III.
This is a draft, with more to add, figures not
yet placed properly, etc. Comments solicited.

https://www.dropbox.com/s/dli62uyuldr7z5q/1x.2_Resistors_DRAFT.pdf?dl=1

a very minor point...

"You often use a high-resistance voltage divider to monitor a high-voltage dc supply,"

do I?

Giant electrostatic voltmeters were fun.



--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Mon, 5 Aug 2019 06:07:50 -0500, "Tim Williams"
<tiwill@seventransistorlabs.com> wrote:

Fig 1x.29 -- what about capacitance of noninductives?

Depends actually which type, Ayrton-Perry should be fine but bifilar
(shorted at one end) will be awful.

Speaking of Ayrton, she was not only one of the first EEs as such, but one
of if not the first female EE. I don't know if that's footnote-worthy, but
it's not well known I think!

Thin film resistors -- I've heard paranoia about these corroding. Any
insight? (Not AoE-specific, anyone's experience will do.) Maybe was a
legitimate concern, now outdated?

Fig 1x.30 is very useful! It looks visually noisy though; could you get
that formatted as a heatmap, or like, drawing dotted or hashed curves around
the general area of each family?

May be worth a note, Fig 1x.31 -- you can flatten out a messy resistor,
sure, but you're just moving the power dissipation from one resistor to the
other. Fatal for signals with a large RF component!

Do you have any data on TO-220 and other power film resistors, in terms of
capacitance to heatsink, or equivalent circuits? And JL's measured
significant "drool" apparently from induction into the heatsink I think, in
such parts?

The Caddock and Ohmite 50r DPAK parts run around 5 pF from element to
tab, and are very fast. They TDR like you would expect, with the
probably-serpentine resistive element looking like a lossy
transmission line. It's all over in a couple hundred picoseconds.

So many directions to explore with only so much time to go around, I know.
:-S Looking forward to the finished book!

Tim

Caddock makes a resistor

https://www.dropbox.com/s/lxq4ujmkvo755uy/HP54006_probe.zip?dl=0

that is almost perfect. Stick a 450 or 950 ohm one in to an SMA female
on the end of a coax, and you get a cheap 3 GHz probe.

HP wanted about $3K for that kit.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Phil Hobbs]

On 8/5/19 10:40 AM, George Herold wrote:

On Sunday, August 4, 2019 at 3:01:45 PM UTC-4, John Larkin wrote:
On 4 Aug 2019 11:27:05 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:

John Larkin wrote...

On 4 Aug 2019 08:20:02 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:

Here's another AoE x-Chapters DRAFT section to
read and think about. 1x.2 Resistors, takes up
aspects of resistors not discussed in AoE III.
This is a draft, with more to add, figures not
yet placed properly, etc. Comments solicited.

https://www.dropbox.com/s/dli62uyuldr7z5q/1x.2_Resistors_DRAFT.pdf?dl=1

Excellent stuff on non-ideal effects and digipots.

If you have time (which I'd guess is unlikely)
you might mention trimpots. They are frowned on
in some circles, but sometimes they are what works.

Yes, use them all the time, adhering to Bob Pease's
suggestion that they not be relied upon for better
than 1% trimming resolution and stability, even the
15-turn ones, IIRC.

What would you advise our readers?


What mostly interests me is using pots to set gain in wideband
DC-coupled circuits, which is difficult to do otherwise. Some pots
have bizarre, high-inductance geometries inside, and some are good to
a couple GHz. But that's kind of niche-y.

We don't use multi-turn pots; they are if anything less settable than
singles. My ROT is that a decent 1-turn pot is settable to about 0.1%
and stable to a few times that. 1% of the pot's range is probably
prudent as a production limit. Dipswitch + pot is extreme but
sometimes the best way to go.
Cermet material? Do you have a favorite brand?

We use a bunch of panel mount pots.. For DC and low freq the Bourns
10 turn pots are nice.

We would also mention Phil H's loaded pot technique. (Which I've only used
once.. but nice to have in your bag-o-tricks.) (You tie a two smaller
resistors from the pot ends to the wiper.. makes a lower value pot with
very fine adjustment.)

Yeah, for settings near mid-scale you get a nice vernier action, but you
can have the whole range if you need it. Figuring out new nonlinear
curves you can get from a loaded pot is recreational, too, like making
AM radios out of 555 timers.

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.net
http://hobbs-eo.com

 

[Klaus Kragelund]

One not so technical thing about resistor arrays is that a quad array is more expensive than 4 single resistors , but production cost is a lot lower for the quad so Cost Of Gods Sold is cheaper for the array

Add to that better matching and drift, but worse PCB routing (if function is spread across the board)

Cheers

Klaus

 

On Sunday, 4 August 2019 16:20:24 UTC+1, Winfield Hill wrote:

Here's another AoE x-Chapters DRAFT section to
read and think about. 1x.2 Resistors, takes up
aspects of resistors not discussed in AoE III.
This is a draft, with more to add, figures not
yet placed properly, etc. Comments solicited.

https://www.dropbox.com/s/dli62uyuldr7z5q/1x.2_Resistors_DRAFT.pdf?dl=1

I don't remember seeing anything on metal staple resistors. Carbon comp got a lot of mention but not carbon film. Were printed-onto-pcb Rs mentioned? I don't remember. Oh, something I don't think was, and am not sure if useful: how may R values you can get from each size of R-pack. Oh, also use of other components as Rs, primarily filament lamps & neon lamps.

Also, and not sure if relevant, R stocking policies for mfrs. Eg if you reduce the number of R values your board takes, it's slightly cheaper to make. Less purchases, less time. Also if you give a range of values in your parts list, as I usually do where practical, you can often sub with what you've got. In some parts of the world that has some use.

Then there's robustness of sm versus TH. And mounting options for power Rs. And the pros & cons of fan cooling...
And of course tricks to avoid the energy lost in power Rs.

Resistors are far from futile.


NT

 

On Monday, 5 August 2019 16:06:19 UTC+1, nor...@googlegroups.com wrote:

tabbypurr wrote:

snip

Figure 1x.39 Including social stuff is only going to irk those who
don't know you from Adam and have no interest.

OTOH, it does add local color reminiscent of Bob Pease to a potentially
dry tome. Although Pease would've probably said something along the
lines of:

John Larkin of Highland Technology wrote a nice explanation of
his pulse-power torture machine in sci.electronics.design ...

This local color also functions as an Easter egg that enables insiders
to feel special, to be "in the know," regardless of how they feel about
Larkin.

Thank you, 73,

We can see it differently. I know Win a little bit from here, but with people I know nothing about that sort of stuff is just noise that gets in the way of the signal. And most readers won't know him at all.

A dry tome? If you don't want that you won't be buying AOE It's a book of engineer's factual info, not a junk soap.


NT

 

[Winfield Hill]

tabbypurr@gmail.com wrote...

A dry tome? If you don't want that you won't be
buying AoE It's a book of engineer's factual
info, not a junk soap.

Thanks, I think. Actually we're a little of each;
we get tired of the endless spreadsheets of parts
data, bench meas, writing dry-tome stuff, and Paul
breaks out in the Big Lebowski, or whatever.
Gotta jazz up the stories.

And we love name dropping. John sends us his huge
resistor fixture, we explode it, damn right we fess
up. Are we gonna post pictures, claim we made it?

OK, could ... Nah.


--
Thanks,
- Win

 

[George Herold]

On Monday, August 5, 2019 at 5:44:56 PM UTC-4, Winfield Hill wrote:

tabbypurr@gmail.com wrote...

A dry tome? If you don't want that you won't be
buying AoE It's a book of engineer's factual
info, not a junk soap.

Thanks, I think. Actually we're a little of each;
we get tired of the endless spreadsheets of parts
data, bench meas, writing dry-tome stuff, and Paul
breaks out in the Big Lebowski, or whatever.
Gotta jazz up the stories.

And we love name dropping. John sends us his huge
resistor fixture, we explode it, damn right we fess
up. Are we gonna post pictures, claim we made it?

OK, could ... Nah.


--
Thanks,
- Win

AoE has always had a relaxed folksy feel. Transistor man, for instance,
is in the first ed.
I'm happy that is not going away. :^)

George H.

 

[Phil Hobbs]

On 8/5/19 9:19 PM, George Herold wrote:

On Monday, August 5, 2019 at 5:44:56 PM UTC-4, Winfield Hill wrote:
tabbypurr@gmail.com wrote...

A dry tome? If you don't want that you won't be
buying AoE It's a book of engineer's factual
info, not a junk soap.

Thanks, I think. Actually we're a little of each;
we get tired of the endless spreadsheets of parts
data, bench meas, writing dry-tome stuff, and Paul
breaks out in the Big Lebowski, or whatever.
Gotta jazz up the stories.

And we love name dropping. John sends us his huge
resistor fixture, we explode it, damn right we fess
up. Are we gonna post pictures, claim we made it?

OK, could ... Nah.


--
Thanks,
- Win

AoE has always had a relaxed folksy feel. Transistor man, for instance,
is in the first ed.
I'm happy that is not going away. :^)

George H.

Transistor man vs Ebers-Moll, mumble frotz. Ebers-Moll for me.

Cheers

Phil Hobbs

(Relaxed and folksy is key, though.)

 

[Jan Panteltje]

On a sunny day (5 Aug 2019 14:44:40 -0700) it happened Winfield Hill
<winfieldhill@yahoo.com> wrote in <qia80802ajs@drn.newsguy.com>:

tabbypurr@gmail.com wrote...

A dry tome? If you don't want that you won't be
buying AoE It's a book of engineer's factual
info, not a junk soap.

Thanks, I think. Actually we're a little of each;
we get tired of the endless spreadsheets of parts
data, bench meas, writing dry-tome stuff, and Paul
breaks out in the Big Lebowski, or whatever.
Gotta jazz up the stories.

And we love name dropping. John sends us his huge
resistor fixture, we explode it, damn right we fess
up. Are we gonna post pictures, claim we made it?

OK, could ... Nah.

You probably know I am not a big fan of your books
amd never have read those apart from the things I found here and on the web.
Now you are moving into the realm of destruction,
have you ever written about construction of things we used and use everyday
such as radio, TV, the old way, how to design one,
how to write the software for the newer systems (DVB-S DVB_T and their newer generations),
as hardware and software is really both an essential part of electronics these days.
I know books have been written by others about that, very good ones,
and you cannot be an expert on everything
but what is part of our daily lives is an essential aspect in my usual NSHO,
but also because I did all that.

You asked for feedback, here it is.

 

On Monday, 5 August 2019 22:44:56 UTC+1, Winfield Hill wrote:

tabbypurr wrote...

A dry tome? If you don't want that you won't be
buying AoE It's a book of engineer's factual
info, not a junk soap.

Thanks, I think. Actually we're a little of each;
we get tired of the endless spreadsheets of parts
data, bench meas, writing dry-tome stuff, and Paul
breaks out in the Big Lebowski, or whatever.
Gotta jazz up the stories.

And we love name dropping. John sends us his huge
resistor fixture, we explode it, damn right we fess
up. Are we gonna post pictures, claim we made it?

OK, could ... Nah.

Some more...
Mains bleeder resistors run within ratings tend to fail.
Typical V ratings for various R types - IIRC you touched on it but didn't give the reader much idea what to expect from what parts, something that surprises many.
HV R stacks & reliability.
Fusible/safety resistors.
V ratings: end to end & case to external differ
V ratings & pots, why so many fail in mains dimmers
Life ratings of power Rs
Reducing cost of power Rs by using distributed small Rs

Maybe one day you'll end up going to a series of books.


NT

 

[David Nadlinger]

On 05.08.19 3:58 PM, John Larkin wrote:

Caddock makes a resistor

https://www.dropbox.com/s/lxq4ujmkvo755uy/HP54006_probe.zip?dl=0

that is almost perfect.

Can you still get those anywhere, or something equivalently proven? I
had a look a while ago for some tricky probing, but couldn't find a
source (in small quantities, anyway).

— David

 

[John Larkin]

On Tue, 06 Aug 2019 05:40:44 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (5 Aug 2019 14:44:40 -0700) it happened Winfield Hill
winfieldhill@yahoo.com> wrote in <qia80802ajs@drn.newsguy.com>:

tabbypurr@gmail.com wrote...

A dry tome? If you don't want that you won't be
buying AoE It's a book of engineer's factual
info, not a junk soap.

Thanks, I think. Actually we're a little of each;
we get tired of the endless spreadsheets of parts
data, bench meas, writing dry-tome stuff, and Paul
breaks out in the Big Lebowski, or whatever.
Gotta jazz up the stories.

And we love name dropping. John sends us his huge
resistor fixture, we explode it, damn right we fess
up. Are we gonna post pictures, claim we made it?

OK, could ... Nah.

You probably know I am not a big fan of your books
amd never have read those apart from the things I found here and on the web.
Now you are moving into the realm of destruction,
have you ever written about construction of things we used and use everyday
such as radio, TV, the old way, how to design one,
how to write the software for the newer systems (DVB-S DVB_T and their newer generations),
as hardware and software is really both an essential part of electronics these days.
I know books have been written by others about that, very good ones,
and you cannot be an expert on everything
but what is part of our daily lives is an essential aspect in my usual NSHO,
but also because I did all that.

You asked for feedback, here it is.

You should get, and read, AoE3. Really.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On 5 Aug 2019 14:44:40 -0700, Winfield Hill <winfieldhill@yahoo.com>
wrote:

tabbypurr@gmail.com wrote...

A dry tome? If you don't want that you won't be
buying AoE It's a book of engineer's factual
info, not a junk soap.

Thanks, I think. Actually we're a little of each;
we get tired of the endless spreadsheets of parts
data, bench meas, writing dry-tome stuff, and Paul
breaks out in the Big Lebowski, or whatever.
Gotta jazz up the stories.

And we love name dropping. John sends us his huge
resistor fixture, we explode it, damn right we fess
up. Are we gonna post pictures, claim we made it?

OK, could ... Nah.

Well, I am a lot better at blowing up parts than you are.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Tue, 6 Aug 2019 10:35:55 +0100, David Nadlinger
<david@klickverbot.at> wrote:

On 05.08.19 3:58 PM, John Larkin wrote:
Caddock makes a resistor

https://www.dropbox.com/s/lxq4ujmkvo755uy/HP54006_probe.zip?dl=0

that is almost perfect.

Can you still get those anywhere, or something equivalently proven? I
had a look a while ago for some tricky probing, but couldn't find a
source (in small quantities, anyway).

— David

Sure, Caddock sells them. I got 5 samples. They are good for probing
kilovolt pulses, too.

Caddock is great to work with and makes some really interesting parts.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

On Tuesday, 6 August 2019 16:12:27 UTC+1, Tom Del Rosso wrote:

Winfield Hill wrote:
Winfield Hill wrote...

I thought this might be in the book, but if you're covering resistors in
depth in the X-Chapters then maybe it's worth remembering there was a
pretty long thread about this and the minimalist solution wasn't obvious
at first.


----------------------------------------------------------------------
Don't do this! Just don't!
John Larkin 1/19/03

OK, every once in a while we need to have a trimpot crank in a little
bit of DC offset into an opamp or something, and there are those nice
+-15 or whatever power rails handy. But I see so many presumably
intelligent engineers do something like this:


+15----------+
|
|
10k
|
|
P
100r O <-------- small offset
T
|
|
10k
|
|
-15----------+


This is a *very*bad*idea*. I recent sold a bunch of
amplifier/discriminator boxes because somebody else did this, among
other dumb things.

So quit doing this. Just quit it.

John

If you think that's bad, I've seen many circuits in the past where adjusting a preset pot to one end of its travel would destroy a transistor. That was somewhat common at one time.


NT

 

[Tom Del Rosso]

Winfield Hill wrote:

Winfield Hill wrote...

Here's another AoE x-Chapters DRAFT section to
read and think about. 1x.2 Resistors, takes up
aspects of resistors not discussed in AoE III.
This is a draft, with more to add, figures not
yet placed properly, etc. Comments solicited.

Ooops, perhaps a bad link, try this one:
https://www.dropbox.com/s/dli62uyuldr7z5q/1x.2_Resistors_Draft.pdf?dl=1

I thought this might be in the book, but if you're covering resistors in
depth in the X-Chapters then maybe it's worth remembering there was a
pretty long thread about this and the minimalist solution wasn't obvious
at first.


----------------------------------------------------------------------
Don't do this! Just don't!
John Larkin 1/19/03

OK, every once in a while we need to have a trimpot crank in a little
bit of DC offset into an opamp or something, and there are those nice
+-15 or whatever power rails handy. But I see so many presumably
intelligent engineers do something like this:


+15----------+
|
|
10k
|
|
P
100r O <-------- small offset
T
|
|
10k
|
|
-15----------+


This is a *very*bad*idea*. I recent sold a bunch of
amplifier/discriminator boxes because somebody else did this, among
other dumb things.

So quit doing this. Just quit it.

John

----------------------------------------------------------------------
Winfield Hill 1/19/03

Has anyone suggested the standard approach?

.. +15----------,
.. |
.. 22k
.. |
.. +-- 100r -- gnd
.. |
.. P
.. 10k O <-------- small offset
.. T
.. |
.. +-- 100r -- gnd
.. |
.. 22k
.. |
.. -15----------'

Thanks,
- Win

----------------------------------------------------------------------
John Larkin 1/19/03

Whose standard?

Really, gentlemen, I am *not* impressed.

John

----------------------------------------------------------------------
Spehro Pefhany 1/20/03

Well, this obvious one has one less part than my other one, and keeps
full voltage on the pot, for what that's worth (not much)


+15
|
p
10K o <--------------10K -----x--- small offset
t |
| 49R9
| |
| 0V
-15.


It's a bit nonlinear and the output impedance varies a teeny bit,
(from 12.5K||49R9 to 10.0K||49.9) but not bad.


Best regards,
Spehro Pefhany

----------------------------------------------------------------------
John Larkin 1/20/03

Bingo. A glass of wine, sir!

John

 

[Tim Williams]

<tabbypurr@gmail.com> wrote in message
news:3a5609d9-916f-4d3e-aea4-af1bbcae445c@googlegroups.com...

If you think that's bad, I've seen many circuits in the past where
adjusting a preset pot to one end of its travel would destroy a
transistor. That was somewhat common at one time.

Y'mean audio amp bias pots? Or the ones without wiper resistors so when
they inevitably go open circuit, the output stage grenades.

I suspect that's far more endemic to equipment in general, than you think.
I've seen far too many things with trimpots of absurd ranges...

It goes the same for simple analog design, as much as digital [hardware]
design, and software design: limit your input domain and output range!
Cover only as much as you need, no more, no less!

The theory of matched ranges, applied to analog, is to say that you have,
say, a cascade of a few stages, including amplifiers and other signal
processing. The output [voltage] range from each one, must be included in
the input range of the next, and so on. And current, at least in terms of
capability (fanout) for voltage-mode circuits. So, even more generally, the
most famous case is simply the (power transfer) impedance matching theorem.

In digital hardware, we're concerned with bit values and patterns, and
devising tests that can explore a predominant fraction of the input space,
and verifying it against the intended output. Failure to do so results in
famous bugs like Pentium FDIV.

In software, we're concerned with functions that take parameters, and what
intended direct effects, and indirect side-effects, they have. Perform
bounds checking. Pass around, say, structs showing the size of your arrays.
Don't do willy-nilly pointer arithmetic! We shouldn't have to put up with
buffer overflows, this isn't 1970... and yet!

....And so for trimpots, use only the range you need, no more, no less.
Trimming out a resistor tolerance? Great, pad that sucker down to the,
whatever, +/-1% range it needs. The circuit should work fundamentally the
same no matter what any trimpot is set to; it should always function safely,
if terribly inaccurately.

Sometimes it's not possible to ensure function under those conditions, or
even safety; in that case, efforts should be redoubled to address those, and
protective measures added to detect and constrain those conditions.

Example: CRT monitors with deflection lockout: beam current is cut off if
deflection (width or height) falls well below the normal adjustable range.
Incidentally, classic TVs usually did this automatically, since horizontal
sweep generated high voltage; wide-sync monitors however had independent HV
supplies, so could dutifully burn a trench straight across the phosphor
screen if deflection were lost and no protection was in place.

Tim

--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/