Low coefficient NTC resistors?...

[Sylvia Else]

Anyone aware of such a thing?

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some reason?

Sylvia

 

[Spehro Pefhany]

On Fri, 10 Dec 2021 22:50:31 +1100, Sylvia Else <sylvia@email.invalid>
wrote:

Anyone aware of such a thing?

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some reason?

Sylvia

Yes, I have purchased custom positive temperature coefficient
resistors in relatively small lots (10K, if memory serves).

They\'re usually in around the tempco of metals and alloys. (a few
thousand ppm per degree C, positive and fairly linear.

You can find a few values of nickel thin film resistors on Digikey
that have a similar tempco.

Putting a resistor in series with a conventional NTC does not work so
well over a wide temperature range because of the nonlinearity of the
thermistor.
--
Best regards,
Spehro Pefhany

 

[Anthony William Sloman]

On Friday, December 10, 2021 at 11:43:16 PM UTC+11, Spehro Pefhany wrote:

On Fri, 10 Dec 2021 22:50:31 +1100, Sylvia Else <syl...@email.invalid
wrote:
Anyone aware of such a thing?

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some reason?

Yes, I have purchased custom positive temperature coefficient
resistors in relatively small lots (10K, if memory serves).

They\'re usually in around the tempco of metals and alloys. (a few
thousand ppm per degree C, positive and fairly linear.

You can find a few values of nickel thin film resistors on Digikey
that have a similar tempco.

Putting a resistor in series with a conventional NTC does not work so
well over a wide temperature range because of the nonlinearity of the
thermistor.

My impression was that nickel thin film resistors were the poor man\'s platinum resistance sensor. They had around the same temperature coefficient - the resistance was more or less proportional to absolute temperature around room temperature. They weren\'t as good as platinum resistance sensors - for one thing they oxidise if they get too hot. Wikipedia says that they go non-linear about about 300 Celcius.

https://www.prelectronics.com/the-fundamentals-of-rtd-temperature-sensors/

https://en.wikipedia.org/wiki/Resistance_thermometer

--
Bill Sloman, Sydney

 

[Lasse Langwadt Christensen]

fredag den 10. december 2021 kl. 12.50.41 UTC+1 skrev Sylvia Else:

Anyone aware of such a thing?

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some reason?

PT1000/PT100 is ~0.4%/C

 

[Spehro Pefhany]

On Fri, 10 Dec 2021 05:43:39 -0800 (PST), Anthony William Sloman
<bill.sloman@ieee.org> wrote:

On Friday, December 10, 2021 at 11:43:16 PM UTC+11, Spehro Pefhany wrote:
On Fri, 10 Dec 2021 22:50:31 +1100, Sylvia Else <syl...@email.invalid
wrote:
Anyone aware of such a thing?

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some reason?

Yes, I have purchased custom positive temperature coefficient
resistors in relatively small lots (10K, if memory serves).

They\'re usually in around the tempco of metals and alloys. (a few
thousand ppm per degree C, positive and fairly linear.

You can find a few values of nickel thin film resistors on Digikey
that have a similar tempco.

Putting a resistor in series with a conventional NTC does not work so
well over a wide temperature range because of the nonlinearity of the
thermistor.

My impression was that nickel thin film resistors were the poor man\'s platinum resistance sensor. They had around the same temperature coefficient - the resistance was more or less proportional to absolute temperature around room temperature. They weren\'t as good as platinum resistance sensors - for one thing they oxidise if they get too hot. Wikipedia says that they go non-linear about about 300 Celcius.

https://www.prelectronics.com/the-fundamentals-of-rtd-temperature-sensors/

https://en.wikipedia.org/wiki/Resistance_thermometer

Propietary nickel alloy base metal sensors are used in HVAC
applications by folks like Honeywell.

Ni120 sensors (wound and now thin film) are traditionally used in some
applications like bearing and motor stator winding temperature
(sometimes they use Cu RTDs for the latter).

The SMT 0603 etc. Vishay ones I was mentioning are pretty awful for
sensors, almost a 10% tolerance on Tempco and a max temperature of
150°C minus self-heating so their applications would be limited. The
ones I sourced from a Japanese factory had much tighter tolerance on
tempco.
--
Best regards,
Spehro Pefhany

 

[server]

On Fri, 10 Dec 2021 10:16:46 -0500, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:

On Fri, 10 Dec 2021 05:43:39 -0800 (PST), Anthony William Sloman
bill.sloman@ieee.org> wrote:

On Friday, December 10, 2021 at 11:43:16 PM UTC+11, Spehro Pefhany wrote:
On Fri, 10 Dec 2021 22:50:31 +1100, Sylvia Else <syl...@email.invalid
wrote:
Anyone aware of such a thing?

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some reason?

Yes, I have purchased custom positive temperature coefficient
resistors in relatively small lots (10K, if memory serves).

They\'re usually in around the tempco of metals and alloys. (a few
thousand ppm per degree C, positive and fairly linear.

You can find a few values of nickel thin film resistors on Digikey
that have a similar tempco.

Putting a resistor in series with a conventional NTC does not work so
well over a wide temperature range because of the nonlinearity of the
thermistor.

My impression was that nickel thin film resistors were the poor man\'s platinum resistance sensor. They had around the same temperature coefficient - the resistance was more or less proportional to absolute temperature around room temperature. They weren\'t as good as platinum resistance sensors - for one thing they oxidise if they get too hot. Wikipedia says that they go non-linear about about 300 Celcius.

https://www.prelectronics.com/the-fundamentals-of-rtd-temperature-sensors/

https://en.wikipedia.org/wiki/Resistance_thermometer

Propietary nickel alloy base metal sensors are used in HVAC
applications by folks like Honeywell.

Ni120 sensors (wound and now thin film) are traditionally used in some
applications like bearing and motor stator winding temperature
(sometimes they use Cu RTDs for the latter).

The SMT 0603 etc. Vishay ones I was mentioning are pretty awful for
sensors, almost a 10% tolerance on Tempco and a max temperature of
150°C minus self-heating so their applications would be limited. The
ones I sourced from a Japanese factory had much tighter tolerance on
tempco.

The ZNI1000 nickel RTD is a cool part. It can be linearized with one
resistor.

Of course, ic temp sensors are cheap and can be had analog or SPI.



--

Father Brown\'s figure remained quite dark and still;
but in that instant he had lost his head. His head was
always most valuable when he had lost it.

 

[Phil Hobbs]

Sylvia Else wrote:

Anyone aware of such a thing?

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some
reason?

Sylvia

The only thing that comes to mind is a diode.

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

 

[Phil Allison]

Stupider than Anyone Else wrote:

Anyone aware of such a thing?

** Yawnnnnnnnn...

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

** Thermal tracking is often built inside the charging controller IC used.

https://www.ti.com/lit/ds/symlink/bq24450.pdf?ts=1639171712003&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FBQ24450




...... Phil

 

[John Larkin]

On Fri, 10 Dec 2021 22:50:31 +1100, Sylvia Else <sylvia@email.invalid>
wrote:

Anyone aware of such a thing?

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some reason?

Sylvia

Carbon comp resistor, roughly -1200 ppm/c.

--

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

 

[David Eather]

On 10/12/2021 9:50 pm, Sylvia Else wrote:

Anyone aware of such a thing?

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some
reason?

Sylvia

lead acid batteries are temperature sensitive when recharging

 

[Anthony William Sloman]

On Saturday, December 11, 2021 at 11:30:50 AM UTC+11, David Eather wrote:

On 10/12/2021 9:50 pm, Sylvia Else wrote:
Anyone aware of such a thing?

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some
reason?

lead acid batteries are temperature sensitive when recharging

All batteries - as electrochemical devices - are temperature sensitive

https://en.wikipedia.org/wiki/Gibbs_free_energy

If you scroll down to \"In electrochemical thermodynamics\" you will get to the Nernst Equation

https://en.wikipedia.org/wiki/Nernst_equation

which can be seen as the Gibbs Free energy equation for electrochemical systems - curiously, Nernst formulated it in 1888 some twelves years after Gibbs had published the more general formulation. Thermodynamics isn\'t easy to get your head around - even if you are as clever as Nernst, who eventually got a Nobel prize in 1920 for his work on the third law of thermodynamics. Once instilled, it does tend to stick - as an undergraduate in 1961 it took me a while to get my head around that particular bit of the chemistry course.

--
Bil Sloman, Sydney

 

[Sylvia Else]

On 11-Dec-21 11:30 am, David Eather wrote:

On 10/12/2021 9:50 pm, Sylvia Else wrote:
Anyone aware of such a thing?

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some
reason?

Sylvia

lead acid batteries are temperature sensitive when recharging

Yes, this is presumably the reason for the NTC resistor in the charging
circuit. But if it has a typical thermistor characteristic, then in this
particular implementation, the compensation will be out by a factor of
ten, which is probably worse than no compensation at all.

I may have to remove it from the circuit to better characterise it.

Sylvia.

 

[Phil Allison]

Stupider than Anybody Else wrote:
==========================

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some
reason?

Sylvia

lead acid batteries are temperature sensitive when recharging

Yes, this is presumably the reason for the NTC resistor in the charging
circuit. But if it has a typical thermistor characteristic, then in this
particular implementation, the compensation will be out by a factor of
ten, which is probably worse than no compensation at all.

I may have to remove it from the circuit to better characterise it.

** WTF are you on about ????

Themistors ( NTC or PTC) do not look like regular resistors.

Are you claiming KNOW there is a resistor ( banded or not ) that has a very large neg tempco in your UPS?

Or just making wild, idiot guesses as bloody usual.



....... Phil

 

[Anthony William Sloman]

On Saturday, December 11, 2021 at 12:02:59 PM UTC+11, Sylvia Else wrote:

On 11-Dec-21 11:30 am, David Eather wrote:
On 10/12/2021 9:50 pm, Sylvia Else wrote:
Anyone aware of such a thing?

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some
reason?

Sylvia

lead acid batteries are temperature sensitive when recharging
Yes, this is presumably the reason for the NTC resistor in the charging
circuit. But if it has a typical thermistor characteristic, then in this
particular implementation, the compensation will be out by a factor of
ten, which is probably worse than no compensation at all.

I may have to remove it from the circuit to better characterise it.

If it is a carbon composition or carbon film resistor it won\'t look much like a thermistor

https://eepower.com/resistor-guide/resistor-materials/carbon-film-resistor/#

The range from -2.5×10-4 Ω/°C to -8×10-4 Ω/°C is quite a bit lower -two orders of magnitude - than the typical NTC thermistor at - -3 to -6x10-2.

It would still be a pretty horrible temperature sensor. The original designers may have been a bit optimistic about the reproducibility and stability of the part they put in.

Carbon film resistors might not have looked quite as cheap and nasty twenty years ago - they did to me back then, but then there were engineers around who saw them as cheap, rather than nasty, and there may still be some who think that way.

--
Bill Sloman, Sydney

 

[Sylvia Else]

On 11-Dec-21 12:10 pm, Phil Allison wrote:

Stupider than Anybody Else wrote:
==========================

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some
reason?

Sylvia

lead acid batteries are temperature sensitive when recharging

Yes, this is presumably the reason for the NTC resistor in the charging
circuit. But if it has a typical thermistor characteristic, then in this
particular implementation, the compensation will be out by a factor of
ten, which is probably worse than no compensation at all.

I may have to remove it from the circuit to better characterise it.


** WTF are you on about ????

Themistors ( NTC or PTC) do not look like regular resistors.

Are you claiming KNOW there is a resistor ( banded or not ) that has a very large neg tempco in your UPS?

Or just making wild, idiot guesses as bloody usual.

Where did I say it looked like an ordinary resistor? It doesn\'t.

Amongst other things, it\'s labelled on the board as NTC001.

It also clearly has a negative temperature coefficient, as demonstrated
by the use of a multimeter and a hair dryer (yes, of course I have a
heat gun, but the hair dryer seemed less likely to damage anything).

It\'s in series with a fixed resistor and a trimmer, which together with
a resistor from the output to the adjustment pin of an LM317T, define
the voltage on that pin, and thus sets the charging voltage for the
batteries.

Is more evidence required?

Sylvia.

 

[Phil Allison]

Stupider than Anybody Else wrote:
==========================

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but my UPS seems to contain a single
component that behaves that way - perhaps less than 1% at 20 Celcius -
it\'s in the circuit that controls the battery charging float voltage.

Did they perhaps exist 20 years ago (when my UPS was made), for some
reason?

Sylvia

lead acid batteries are temperature sensitive when recharging

Yes, this is presumably the reason for the NTC resistor in the charging
circuit. But if it has a typical thermistor characteristic, then in this
particular implementation, the compensation will be out by a factor of
ten, which is probably worse than no compensation at all.

I may have to remove it from the circuit to better characterise it.


** WTF are you on about ????

Themistors ( NTC or PTC) do not look like regular resistors.

Are you claiming KNOW there is a resistor ( banded or not ) that has a very large neg tempco in your UPS?

Or just making wild, idiot guesses as bloody usual.


Where did I say it looked like an ordinary resistor?

** In the heading - fuckwit.

Amongst other things, it\'s labelled on the board as NTC001.

** What other crucial facts have you omitted ??

It also clearly has a negative temperature coefficient, as demonstrated
by the use of a multimeter and a hair dryer (yes, of course I have a
heat gun, but the hair dryer seemed less likely to damage anything).

** OK, so that is one of them.

> It\'s in series with a fixed resistor and a trimmer,

** Why did you LIE and hide info in your first post ?

which together with
a resistor from the output to the adjustment pin of an LM317T, define
the voltage on that pin, and thus sets the charging voltage for the
batteries.

** Charging and float voltages are not the same.

> Is more evidence required?

** None more needed to prove what a time wasting troll you are.


...... Phil

 

[whit3rd]

On Friday, December 10, 2021 at 6:44:44 AM UTC-8, lang...@fonz.dk wrote:

fredag den 10. december 2021 kl. 12.50.41 UTC+1 skrev Sylvia Else:
Anyone aware of such a thing?

Clearly, one can achieve that just by putting a thermistor in series
with an ordinary resistor, but ...

PT1000/PT100 is ~0.4%/C

Oh, that\'s just about true for all classical metals; getting a non-PTAT (proportional
to absolute temperature) resistor is a notable materials-science achievement.

At 20 C, proportional to absolute temperature means about 0.0034 per kelvin; for
copper, resistance goes 0.00386, for tungsten 0.0045, for aluminum 0.00429,
for platinum 0.0039 ... The impure (alloyed) metals used for low tempco have
very non-ideal metallic nature.

 

[Phil Allison]

The biggest Fuckwit on Usenet posts as whit3rd
====================================

PT1000/PT100 is ~0.4%/C

Oh, that\'s just about true for all classical metals; getting a non-PTAT (proportional
to absolute temperature) resistor is a notable materials-science achievement.

At 20 C, proportional to absolute temperature means about 0.0034 per kelvin; for
copper, resistance goes 0.00386, for tungsten 0.0045, for aluminum 0.00429,
for platinum 0.0039 ...

The impure (alloyed) metals used for low tempco have very non-ideal metallic nature.

** \" very non- ideal metallic nature\" ???????

Could you please be bit more ambiguous ??

Cos some fuckheads here will imagine it makes sense.



....... Phil

 

[Anthony William Sloman]

On Saturday, December 11, 2021 at 1:14:23 PM UTC+11, palli...@gmail.com wrote:

The biggest Fuckwit on Usenet posts as whit3rd
===================================
PT1000/PT100 is ~0.4%/C

Oh, that\'s just about true for all classical metals; getting a non-PTAT (proportional
to absolute temperature) resistor is a notable materials-science achievement.

At 20 C, proportional to absolute temperature means about 0.0034 per kelvin; for
copper, resistance goes 0.00386, for tungsten 0.0045, for aluminum 0.00429,
for platinum 0.0039 ...

The impure (alloyed) metals used for low tempco have very non-ideal metallic nature.

** \" very non- ideal metallic nature\" ???????

Could you please be bit more ambiguous ??

Cos some fuckheads here will imagine it makes sense.

Back when I was in paid work we got a marketing talk from Vishay on their very low temperature coefficient resistors which could get below +/-5ppm per degree Celcius, if you were willing to buy their most expensive parts (which we were, if not all that often).

They not only mucked about with the composition of the materials they laid down in their thin films, but they also figured in temperature generated strain by laying down material with one cofficient of thermal expansion on a substrate with a a different one. This is a longer way of saying that they got non-ideal behaviour. I can see whit3rd might have wanted to avoid testing your attention span (which isn\'t all that long).

--
Bill Sloman, Sydney

 

[Phil Allison]

IEEE Bill ....@ieee.org wrote:

===========================

The biggest Fuckwit on Usenet posts as whit3rd
====================================

PT1000/PT100 is ~0.4%/C

Oh, that\'s just about true for all classical metals; getting a non-PTAT (proportional
to absolute temperature) resistor is a notable materials-science achievement.

At 20 C, proportional to absolute temperature means about 0.0034 per kelvin; for
copper, resistance goes 0.00386, for tungsten 0.0045, for aluminum 0.00429,
for platinum 0.0039 ...

The impure (alloyed) metals used for low tempco have very non-ideal metallic nature.

** \" very non- ideal metallic nature\" ???????

Could you please be bit more ambiguous ??

Cos some fuckheads here will imagine it makes sense.


They not only mucked about with the composition of the materials they laid down in their thin films,
but they also figured in temperature generated strain by laying down material with one cofficient
of thermal expansion on a substrate with a a different one.
This is a longer way of saying that they got non-ideal behaviour.

** The witless moron posted about PURE METALS & low tempco metal alloys.

You bullshitting, ridiculous ARSEHOLE !!!






...... Phil