\"Shunt\" Resistors...

[Ricketty C]

On Wednesday, October 7, 2020 at 3:18:01 PM UTC-4, Joerg wrote:

On 10/7/20 8:08 AM, jlarkin@highlandsniptechnology.com wrote:
On Wed, 07 Oct 2020 09:06:10 -0400, legg <legg@nospam.magma.ca
wrote:

On Tue, 6 Oct 2020 10:37:19 -0700 (PDT), Ricketty C
gnuarm.deletethisbit@gmail.com> wrote:

I recall designing circuits for analog meters with current shunt
resistors. In the last thirty years my measurements are all done
by measuring voltage across series resistor. Is this resistor
still referred to as a \"shunt\"? ...


Even though that would technically be a current sense resistor some
still call it shunt. Or in the UK \"shoont\"


... Even though it is no longer
shunting current around a current meter, obsolete terminology
often remains. An example is calling the AC-DC power supply in
an LED replacement for a fluorescent lamp a \"ballast\".


Same as some people call an electronic dimmer a rheostat. It\'s wrong but
everyone old enough knows what is meant.


Do you refer to the series current sense resistor a \"shunt\"?

Both terms are simple and quick expanations of a component\'s
function.

This practice is sometimes mis-used, but I think you\'ve picked the
wrong examples to shake your stick at.

RL

We use a lot of shorthand terms that make language purists who don\'t
design things get all prissy.


The first one I learned in industry was \"fudge factor\". Our professors
would have been disgusted.

I guess you had some funny professors. I had teachers who used the term for constants that are not fundamental or for unit conversion... i.e. experimentally determined. We probably had more of that in chemistry than in EE.

--

Rick C.

-+ Get 1,000 miles of free Supercharging
-+ Tesla referral code - https://ts.la/richard11209

 

[Flyguy]

On Tuesday, October 6, 2020 at 10:37:25 AM UTC-7, Ricketty C wrote:

I recall designing circuits for analog meters with current shunt resistors. In the last thirty years my measurements are all done by measuring voltage across series resistor. Is this resistor still referred to as a \"shunt\"? Even though it is no longer shunting current around a current meter, obsolete terminology often remains. An example is calling the AC-DC power supply in an LED replacement for a fluorescent lamp a \"ballast\".

Do you refer to the series current sense resistor a \"shunt\"?

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

Yes, it is still called a \"shunt\" resistor as the resistor is in parallel with the meter, not the load, although they also refer to it as a \"current sense\" resistor.
https://eepower.com/resistor-guide/resistor-applications/shunt-resistor/#

 

[Phil Hobbs]

On 2020-10-07 15:01, Lasse Langwadt Christensen wrote:

onsdag den 7. oktober 2020 kl. 20.27.27 UTC+2 skrev Ricketty C:
On Wednesday, October 7, 2020 at 2:18:01 PM UTC-4,
jrwal...@gmail.com wrote:
On Wednesday, 7 October 2020 16:06:09 UTC+1,
jla...@highlandsniptechnology.com wrote:

The manganin sheet stock that we bought had a zero TC around
60C, which was the temperature of the heated block that we
glued our shunts to. One can also buy manganin that has its
flat spot at room temp.

Punching and bending wrecked the TC, and annealing fixed it
again.

Other alloys, like zerodur and something else, were much better
but hard to get.

An electricity meter manufacturer I am familiar with use a
manganin strip electron beam welded to copper busbars to avoid
some of these issues - especially the avoidance of contamination
and stress.

We needed wideband current sensing to make PPM-precise pulses,
and got interesting eddy-current effects (looked like series
inductance, make voltage overshoots) from the shunt being flat
against the aluminum block. We found a fix for that.
Narrow slots milled into the surface of the Al block or
insulating spacer?

Annealing is a black art. I knew a French guy who got the
permeability of metglas up to 1e6 by a secret annealing
process.

Yes, I used to anneal Mumetal in a hydrogen atmosphere. It made
the workshop manager very nervous.

That\'s a little bit funny. A hydrogen atmosphere is not really any
more dangerous than oxygen. We breath that stuff! It\'s when the
two are mixed that you can have problems. I assume this would have
been in a small volume?


hydrogen only takes a few uJ to ignite, it burns in any ratio with
air from 4-75%, explodes in mixtures from 18-60%

In the solid-state physics world (back when I was doing that) we solved
the problem by annealing in _forming gas_, which is 98% N2 and 2% H2.

It won\'t burn in any mixture with ambient air, and for many things it
works just as well as H2. Of course it doesn\'t always suffice, because
some substrates react with nitrogen.

Thirty years ago, my late (and very dear) friend Don DeCain and I built
a gizmo for finding micron-sized particles floating around inside
hydrogen-filled belt ovens used for sintering ceramic and glass-ceramic
substrates for IBM mainframes.

The ovens were about 30 feet long and 5-6 feet in height and width, and
contained a conveyor belt down which the substrates travelled. They
were about 100 mm square, with well over 100 layers. The original ones
were alumina ceramic with (iirc) tantalum metal paste, which AFAIK never
had a single field failure. Alumina has an epsilon of about 10, though,
which slowed them down. (Later ones were glass-ceramic with copper
wiring, which is a whole saga in itself.)

This was in IBM\'s East Fishkill plant, building 322, and that whole end
of the building was made of blast doors--both walls and roof. At the
time (1990ish), IBM was the world\'s second largest industrial user of
hydrogen, after NASA. Every time a substrate came out, a door opened
and a spout of fire came out.

It really was a lot like the throne room of the Great Oz.

Forming gas works for a lot of applications--less dramatic but much safer.

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

 

[Ricketty C]

On Wednesday, October 7, 2020 at 7:38:55 PM UTC-4, Flyguy wrote:

On Tuesday, October 6, 2020 at 10:37:25 AM UTC-7, Ricketty C wrote:
I recall designing circuits for analog meters with current shunt resistors. In the last thirty years my measurements are all done by measuring voltage across series resistor. Is this resistor still referred to as a \"shunt\"? Even though it is no longer shunting current around a current meter, obsolete terminology often remains. An example is calling the AC-DC power supply in an LED replacement for a fluorescent lamp a \"ballast\".

Do you refer to the series current sense resistor a \"shunt\"?

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

Yes, it is still called a \"shunt\" resistor as the resistor is in parallel with the meter, not the load, although they also refer to it as a \"current sense\" resistor.
https://eepower.com/resistor-guide/resistor-applications/shunt-resistor/#

Interesting, but your source seems to be inconsistent with their terminology.

Definition shunt resistor
A shunt resistor is used to measure electric current, alternating or direct. This is done by measuring the voltage drop across the resistor.

They go on at great length to talk about \"shunting\" current around a more sensitive current meter to measure higher currents. They also talk about \"shunting\" current around something for other purposes such as a crowbar circuit. I don\'t see them discuss using a voltmeter to measure the voltage at all although they do mention that a shunt can be specified with a current and a corresponding voltage rather than simply the resistance.

No matter. It just struck me odd the term was used this way. I\'ve never called it a shunt resistor unless it was shunting current around a current meter. I actually have much bigger problems with the guy. I don\'t have a rig to test so he has to take measurements and provide them to me. He is really, really poor at understanding what is going on electrically. He doesn\'t understand that he should see the same voltage at both ends of a wire connection for example. It makes it hard to know what to ask him to do sometimes because I don\'t know if it will produce anything useful. I\'ve been trying for over a month to get him to take the measurements to verify the battery charger is working. He took some measurements that left out the input voltage from the power brick which is needed to know the current across the \"shunt\" resistor measuring the input current. He also doesn\'t understand that an open collector output that has no pullup has to be measured to ground with an ohm meter even though I\'ve told him this half a dozen times in messages and verbally.

I would go on and rant about how he won\'t spend any time writing requirements and make major changes after work has been done, but time is short and I need to get back to what I was doing.

Thanks for the link.

--

Rick C.

+- Get 1,000 miles of free Supercharging
+- Tesla referral code - https://ts.la/richard11209

 

[server]

On Wed, 7 Oct 2020 12:17:50 -0700, Joerg <news@analogconsultants.com>
wrote:

On 10/7/20 8:08 AM, jlarkin@highlandsniptechnology.com wrote:
On Wed, 07 Oct 2020 09:06:10 -0400, legg <legg@nospam.magma.ca
wrote:

On Tue, 6 Oct 2020 10:37:19 -0700 (PDT), Ricketty C
gnuarm.deletethisbit@gmail.com> wrote:

I recall designing circuits for analog meters with current shunt
resistors. In the last thirty years my measurements are all done
by measuring voltage across series resistor. Is this resistor
still referred to as a \"shunt\"? ...


Even though that would technically be a current sense resistor some
still call it shunt. Or in the UK \"shoont\"


... Even though it is no longer
shunting current around a current meter, obsolete terminology
often remains. An example is calling the AC-DC power supply in
an LED replacement for a fluorescent lamp a \"ballast\".


Same as some people call an electronic dimmer a rheostat. It\'s wrong but
everyone old enough knows what is meant.


Do you refer to the series current sense resistor a \"shunt\"?

Both terms are simple and quick expanations of a component\'s
function.

This practice is sometimes mis-used, but I think you\'ve picked the
wrong examples to shake your stick at.

RL

We use a lot of shorthand terms that make language purists who don\'t
design things get all prissy.


The first one I learned in industry was \"fudge factor\". Our professors
would have been disgusted.

[...]

Academics want a lot of provable math. A real engineer does whatever
it takes to make a thing work.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Phil Hobbs]

On 2020-10-07 22:08, jlarkin@highlandsniptechnology.com wrote:

On Wed, 7 Oct 2020 12:17:50 -0700, Joerg <news@analogconsultants.com
wrote:

On 10/7/20 8:08 AM, jlarkin@highlandsniptechnology.com wrote:
On Wed, 07 Oct 2020 09:06:10 -0400, legg <legg@nospam.magma.ca
wrote:

On Tue, 6 Oct 2020 10:37:19 -0700 (PDT), Ricketty C
gnuarm.deletethisbit@gmail.com> wrote:

I recall designing circuits for analog meters with current shunt
resistors. In the last thirty years my measurements are all done
by measuring voltage across series resistor. Is this resistor
still referred to as a \"shunt\"? ...


Even though that would technically be a current sense resistor some
still call it shunt. Or in the UK \"shoont\"


... Even though it is no longer
shunting current around a current meter, obsolete terminology
often remains. An example is calling the AC-DC power supply in
an LED replacement for a fluorescent lamp a \"ballast\".


Same as some people call an electronic dimmer a rheostat. It\'s wrong but
everyone old enough knows what is meant.


Do you refer to the series current sense resistor a \"shunt\"?

Both terms are simple and quick expanations of a component\'s
function.

This practice is sometimes mis-used, but I think you\'ve picked the
wrong examples to shake your stick at.

RL

We use a lot of shorthand terms that make language purists who don\'t
design things get all prissy.


The first one I learned in industry was \"fudge factor\". Our professors
would have been disgusted.

[...]

Academics want a lot of provable math. A real engineer does whatever
it takes to make a thing work.

Yeah, as long as it works many times and not just once on the bench.

The most useful ad-hoc math aid is Finagle\'s Constant, which when
multiplied by the answer you got gives the answer you should have
gotten. (I once applied that by name in an undergraduate physics
problem set, and got full marks. Cheers for TAs with a sense of humour.)

Tally-ho

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

 

[John Larkin]

On Thu, 8 Oct 2020 09:49:21 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-10-07 22:08, jlarkin@highlandsniptechnology.com wrote:
On Wed, 7 Oct 2020 12:17:50 -0700, Joerg <news@analogconsultants.com
wrote:

On 10/7/20 8:08 AM, jlarkin@highlandsniptechnology.com wrote:
On Wed, 07 Oct 2020 09:06:10 -0400, legg <legg@nospam.magma.ca
wrote:

On Tue, 6 Oct 2020 10:37:19 -0700 (PDT), Ricketty C
gnuarm.deletethisbit@gmail.com> wrote:

I recall designing circuits for analog meters with current shunt
resistors. In the last thirty years my measurements are all done
by measuring voltage across series resistor. Is this resistor
still referred to as a \"shunt\"? ...


Even though that would technically be a current sense resistor some
still call it shunt. Or in the UK \"shoont\"


... Even though it is no longer
shunting current around a current meter, obsolete terminology
often remains. An example is calling the AC-DC power supply in
an LED replacement for a fluorescent lamp a \"ballast\".


Same as some people call an electronic dimmer a rheostat. It\'s wrong but
everyone old enough knows what is meant.


Do you refer to the series current sense resistor a \"shunt\"?

Both terms are simple and quick expanations of a component\'s
function.

This practice is sometimes mis-used, but I think you\'ve picked the
wrong examples to shake your stick at.

RL

We use a lot of shorthand terms that make language purists who don\'t
design things get all prissy.


The first one I learned in industry was \"fudge factor\". Our professors
would have been disgusted.

[...]

Academics want a lot of provable math. A real engineer does whatever
it takes to make a thing work.

Yeah, as long as it works many times and not just once on the bench.

True. Equations tend to be reliable.

 

[Flyguy]

On Thursday, October 8, 2020 at 6:49:30 AM UTC-7, Phil Hobbs wrote:

On 2020-10-07 22:08, jlarkin@highlandsniptechnology.com wrote:
On Wed, 7 Oct 2020 12:17:50 -0700, Joerg <news@analogconsultants.com
wrote:

On 10/7/20 8:08 AM, jlarkin@highlandsniptechnology.com wrote:
On Wed, 07 Oct 2020 09:06:10 -0400, legg <legg@nospam.magma.ca
wrote:

On Tue, 6 Oct 2020 10:37:19 -0700 (PDT), Ricketty C
gnuarm.deletethisbit@gmail.com> wrote:

I recall designing circuits for analog meters with current shunt
resistors. In the last thirty years my measurements are all done
by measuring voltage across series resistor. Is this resistor
still referred to as a \"shunt\"? ...


Even though that would technically be a current sense resistor some
still call it shunt. Or in the UK \"shoont\"


... Even though it is no longer
shunting current around a current meter, obsolete terminology
often remains. An example is calling the AC-DC power supply in
an LED replacement for a fluorescent lamp a \"ballast\".


Same as some people call an electronic dimmer a rheostat. It\'s wrong but
everyone old enough knows what is meant.


Do you refer to the series current sense resistor a \"shunt\"?

Both terms are simple and quick expanations of a component\'s
function.

This practice is sometimes mis-used, but I think you\'ve picked the
wrong examples to shake your stick at.

RL

We use a lot of shorthand terms that make language purists who don\'t
design things get all prissy.


The first one I learned in industry was \"fudge factor\". Our professors
would have been disgusted.

[...]

Academics want a lot of provable math. A real engineer does whatever
it takes to make a thing work.

Yeah, as long as it works many times and not just once on the bench.

The most useful ad-hoc math aid is Finagle\'s Constant, which when
multiplied by the answer you got gives the answer you should have
gotten. (I once applied that by name in an undergraduate physics
problem set, and got full marks. Cheers for TAs with a sense of humour.)

Tally-ho

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

Engineers are a hell of a lot more precise than other disciplines. Michael Mann\'s \"trick\" to hide the decline comes to mind:
http://joannenova.com.au/2014/09/manns-trick-to-hide-the-decline-still-shocking/

 

[whit3rd]

On Thursday, October 8, 2020 at 7:44:34 PM UTC-7, Flyguy wrote:

Engineers are a hell of a lot more precise than other disciplines. Michael Mann\'s \"trick\" to hide the decline comes to mind:
http://joannenova.com.au/2014/09/manns-trick-to-hide-the-decline-still-shocking/

Liars can look at a graph and say they\'re shocked, is all we can learn from that reference.
The multiple curves on the graph are accurate representations, but to make sense of them
you have to actually READ the labels. Mann didn\'t use any trick except superimposing multiple
curves on a single timeline. There was no \'hide the decline\'.

What does that have to do with precision?

 

[Bill Sloman]

On Thursday, October 8, 2020 at 1:09:01 PM UTC+11, jla...@highlandsniptechnology.com wrote:

On Wed, 7 Oct 2020 12:17:50 -0700, Joerg <ne...@analogconsultants.com
wrote:
On 10/7/20 8:08 AM, jla...@highlandsniptechnology.com wrote:
On Wed, 07 Oct 2020 09:06:10 -0400, legg <le...@nospam.magma.ca
wrote:

On Tue, 6 Oct 2020 10:37:19 -0700 (PDT), Ricketty C
gnuarm.del...@gmail.com> wrote:

<snip>

Do you refer to the series current sense resistor a \"shunt\"?

Both terms are simple and quick expanations of a component\'s
function.

This practice is sometimes mis-used, but I think you\'ve picked the
wrong examples to shake your stick at.

We use a lot of shorthand terms that make language purists who don\'t
design things get all prissy.

Since using the wrong word usually means that you haven\'t thought hard enough about what you are doing, it\'s usually not the the choice of word that they are getting prissy about. Sloppy engineers do go in for that sort of evasion.

The first one I learned in industry was \"fudge factor\". Our professors
would have been disgusted.

[...]
Academics want a lot of provable math. A real engineer does whatever
it takes to make a thing work.

Real engineers can use math to get something that not only works, but works pretty much as well as it could.

\"An engineer is someone who can do with one dollar what any damned fool could do with two\".

I\'ve cleaned up after enough \"whatever it takes\" engineers to get pretty prissy about their habits.

--
Bill Sloman, Sydney

 

[Tom Gardner]

On 11/10/20 06:42, Bill Sloman wrote:
> I\'ve cleaned up after enough \"whatever it takes\" engineers to get pretty prissy about their habits.


Especially softies