Re: [time-nuts] Low CostTemperature sensor

2017-01-17 Thread William H. Fite 
Orin is correct. To refer to an exponential relationship as directly
proportional is erroneous yet people use it that way commonly and everybody
knows what they mean. It just sets the teeth of statisticians like me on
edge.

On Tue, Jan 17, 2017 at 12:46 PM, Orin Eman  wrote:

> Directly proportional implies a relationship of the form y = c * x where c
> is a constant and * is multiplication.  So it is linear.
>
> To call an exponential relationship "directly proportional" would be wrong.
>
> On Tue, Jan 17, 2017 at 1:17 AM, Charles Steinmetz 
> wrote:
>
> > Tom wrote:
> >
> > That article has a major error. Anyone know what it is?
> >>
> >
> > Well, the author says the reverse current of a diode is "directly"
> > proportional to temperature.  This could suggest that he means the
> > relationship is linear (the relationship is actually exponential with
> > absolute temperature).  But that's not really an *error* -- just sloppy.
> > "Direct" does not necessarily imply "linear."  An exponential
> relationship
> > is "direct" in the sense that it is what mathematicians call "injective"
> > (every temperature corresponds to exactly one value of reverse current).
> >
> > Then, in discussing the LM95235, he says that it can use the
> > "collector-emitter junction diode" of a transistor as the sense element.
> > Of course, a bipolar transistor has no collector-emitter junction. His
> > diagram correctly shows a diode-connected NPN operating in the active
> > region (forward biased, not reverse biased as the rest of his article
> > discusses) as the sensor for the LM95235.
> >
> > Are any of these what you had in mind, or is there more?
> >
> > Charles
> >
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Re: [time-nuts] Low CostTemperature sensor

2017-01-17 Thread Orin Eman 
Directly proportional implies a relationship of the form y = c * x where c
is a constant and * is multiplication.  So it is linear.

To call an exponential relationship "directly proportional" would be wrong.

On Tue, Jan 17, 2017 at 1:17 AM, Charles Steinmetz 
wrote:

> Tom wrote:
>
> That article has a major error. Anyone know what it is?
>>
>
> Well, the author says the reverse current of a diode is "directly"
> proportional to temperature.  This could suggest that he means the
> relationship is linear (the relationship is actually exponential with
> absolute temperature).  But that's not really an *error* -- just sloppy.
> "Direct" does not necessarily imply "linear."  An exponential relationship
> is "direct" in the sense that it is what mathematicians call "injective"
> (every temperature corresponds to exactly one value of reverse current).
>
> Then, in discussing the LM95235, he says that it can use the
> "collector-emitter junction diode" of a transistor as the sense element.
> Of course, a bipolar transistor has no collector-emitter junction. His
> diagram correctly shows a diode-connected NPN operating in the active
> region (forward biased, not reverse biased as the rest of his article
> discusses) as the sensor for the LM95235.
>
> Are any of these what you had in mind, or is there more?
>
> Charles
>
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/m
> ailman/listinfo/time-nuts
> and follow the instructions there.
>
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Re: [time-nuts] Low CostTemperature sensor

2017-01-17 Thread Tom Miller 
I agree with both of you. I can't imagine using the reverse leakage of a 
diode to measure temperature without some difficult and expensive design. 
Also, the transistor is using the forward biased B-E diode against what he 
stated in the article.


And sloppy would be the best description.

Thanks guys. Glad I am not the only one forming that opinion.

Regards,
Tom


- Original Message - 
From: "Scott Stobbe" <scott.j.sto...@gmail.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts@febo.com>

Sent: Tuesday, January 17, 2017 9:10 AM
Subject: Re: [time-nuts] Low CostTemperature sensor



Thermometry based on Diode leakage current wouldn't be impossible I
suppose, you might loose some hair in the process.

The signal levels on the opamp are goofed too.

On Tue, Jan 17, 2017 at 4:19 AM Charles Steinmetz <csteinm...@yandex.com>
wrote:


Tom wrote:



> That article has a major error. Anyone know what it is?



Well, the author says the reverse current of a diode is "directly"

proportional to temperature.  This could suggest that he means the

relationship is linear (the relationship is actually exponential with

absolute temperature).  But that's not really an *error* -- just sloppy.

  "Direct" does not necessarily imply "linear."  An exponential

relationship is "direct" in the sense that it is what mathematicians

call "injective" (every temperature corresponds to exactly one value of

reverse current).



Then, in discussing the LM95235, he says that it can use the

"collector-emitter junction diode" of a transistor as the sense element.

  Of course, a bipolar transistor has no collector-emitter junction.

His diagram correctly shows a diode-connected NPN operating in the

active region (forward biased, not reverse biased as the rest of his

article discusses) as the sensor for the LM95235.



Are any of these what you had in mind, or is there more?



Charles



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Re: [time-nuts] Low CostTemperature sensor

2017-01-17 Thread Scott Stobbe 
 Thermometry based on Diode leakage current wouldn't be impossible I
suppose, you might loose some hair in the process.

The signal levels on the opamp are goofed too.

On Tue, Jan 17, 2017 at 4:19 AM Charles Steinmetz 
wrote:

> Tom wrote:
>
>
>
> > That article has a major error. Anyone know what it is?
>
>
>
> Well, the author says the reverse current of a diode is "directly"
>
> proportional to temperature.  This could suggest that he means the
>
> relationship is linear (the relationship is actually exponential with
>
> absolute temperature).  But that's not really an *error* -- just sloppy.
>
>   "Direct" does not necessarily imply "linear."  An exponential
>
> relationship is "direct" in the sense that it is what mathematicians
>
> call "injective" (every temperature corresponds to exactly one value of
>
> reverse current).
>
>
>
> Then, in discussing the LM95235, he says that it can use the
>
> "collector-emitter junction diode" of a transistor as the sense element.
>
>   Of course, a bipolar transistor has no collector-emitter junction.
>
> His diagram correctly shows a diode-connected NPN operating in the
>
> active region (forward biased, not reverse biased as the rest of his
>
> article discusses) as the sensor for the LM95235.
>
>
>
> Are any of these what you had in mind, or is there more?
>
>
>
> Charles
>
>
>
> ___
>
> time-nuts mailing list -- time-nuts@febo.com
>
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>
> and follow the instructions there.
>
>
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Re: [time-nuts] Low CostTemperature sensor

2017-01-17 Thread Charles Steinmetz 

Tom wrote:


That article has a major error. Anyone know what it is?


Well, the author says the reverse current of a diode is "directly" 
proportional to temperature.  This could suggest that he means the 
relationship is linear (the relationship is actually exponential with 
absolute temperature).  But that's not really an *error* -- just sloppy. 
 "Direct" does not necessarily imply "linear."  An exponential 
relationship is "direct" in the sense that it is what mathematicians 
call "injective" (every temperature corresponds to exactly one value of 
reverse current).


Then, in discussing the LM95235, he says that it can use the 
"collector-emitter junction diode" of a transistor as the sense element. 
 Of course, a bipolar transistor has no collector-emitter junction. 
His diagram correctly shows a diode-connected NPN operating in the 
active region (forward biased, not reverse biased as the rest of his 
article discusses) as the sensor for the LM95235.


Are any of these what you had in mind, or is there more?

Charles

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Re: [time-nuts] Low CostTemperature sensor

2017-01-16 Thread Tom Miller 

That article has a major error. Anyone know what it is?



- Original Message - 
From: "Jason Ball" <ja...@ball.net>
To: "Discussion of precise time and frequency measurement" 
<time-nuts@febo.com>

Cc: "Perry Sandeen" <sandee...@yahoo.com>
Sent: Tuesday, January 17, 2017 1:11 AM
Subject: Re: [time-nuts] Low CostTemperature sensor



Even cheaper... Diiode as a cheap sensor ?

https://www.arrow.com/en/research-and-events/articles/using-a-simple-diode-as-a-ballpark-temperature-sensor


On Tue, Jan 17, 2017 at 4:16 PM, Bill Hawkins <bill.i...@pobox.com> wrote:


Perrier,

Google finds a Siemens NI1000 sensor that follows the nickel curve.
Nickel is popular in industrial control for cost, but not as accurate as
platinum. Converting the platinum curve to accurate temperatures
requires a second order equation, but has been done with 0.1% analog
converters.

Digi-key has ZNI devices as surface mount parts. Sparse data said
nothing about a platinum curve.

I'm curious because my former employer did very well selling platinum
RTD sensors, usually 100 ohms at the triple point.

Bill Hawkins


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Perry
Sandeen via time-nuts
Sent: Monday, January 16, 2017 9:33 PM
To: time-nuts@febo.com
Subject: [time-nuts] Low CostTemperature sensor

List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature
sensor.
It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K
ohm sensors.
It's about $3 from Digi-Key.
FWIW YMMY
Regards,
Perrier
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Re: [time-nuts] Low CostTemperature sensor

2017-01-16 Thread Jason Ball 
Even cheaper... Diiode as a cheap sensor ?

https://www.arrow.com/en/research-and-events/articles/using-a-simple-diode-as-a-ballpark-temperature-sensor


On Tue, Jan 17, 2017 at 4:16 PM, Bill Hawkins <bill.i...@pobox.com> wrote:

> Perrier,
>
> Google finds a Siemens NI1000 sensor that follows the nickel curve.
> Nickel is popular in industrial control for cost, but not as accurate as
> platinum. Converting the platinum curve to accurate temperatures
> requires a second order equation, but has been done with 0.1% analog
> converters.
>
> Digi-key has ZNI devices as surface mount parts. Sparse data said
> nothing about a platinum curve.
>
> I'm curious because my former employer did very well selling platinum
> RTD sensors, usually 100 ohms at the triple point.
>
> Bill Hawkins
>
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Perry
> Sandeen via time-nuts
> Sent: Monday, January 16, 2017 9:33 PM
> To: time-nuts@febo.com
> Subject: [time-nuts] Low CostTemperature sensor
>
> List,
> A while back there was much discussion about temperature sensors.
> One simple inexpensive one to consider would be the ZNI1000Temperature
> sensor.
> It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K
> ohm sensors.
> It's about $3 from Digi-Key.
> FWIW YMMY
> Regards,
> Perrier
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> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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> and follow the instructions there.
>



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--
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callsign: vk2vjb
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Re: [time-nuts] Low CostTemperature sensor

2017-01-16 Thread Bill Hawkins 
Perrier,

Google finds a Siemens NI1000 sensor that follows the nickel curve.
Nickel is popular in industrial control for cost, but not as accurate as
platinum. Converting the platinum curve to accurate temperatures
requires a second order equation, but has been done with 0.1% analog
converters.

Digi-key has ZNI devices as surface mount parts. Sparse data said
nothing about a platinum curve.

I'm curious because my former employer did very well selling platinum
RTD sensors, usually 100 ohms at the triple point.

Bill Hawkins


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Perry
Sandeen via time-nuts
Sent: Monday, January 16, 2017 9:33 PM
To: time-nuts@febo.com
Subject: [time-nuts] Low CostTemperature sensor

List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature
sensor.
It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K
ohm sensors.
It's about $3 from Digi-Key.
FWIW YMMY
Regards,
Perrier
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[time-nuts] Low CostTemperature sensor

2017-01-16 Thread Perry Sandeen via time-nuts 
List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature sensor.
It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K ohm 
sensors.
It's about $3 from Digi-Key. 
FWIW YMMY
Regards,
Perrier
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