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Re: really idiotic, even by EE Times standards
On Thursday, July 6, 2017 at 7:21:14 AM UTC-7, David Brown wrote:  

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Really; it tells you that they are equally accurate.  By definition.  


  
are equal (room) temperatures,   That's how you make multiple standards  
interoperable.   The silly  'degree' symbol, on the other hand, is a nuisan
ce.

Re: really idiotic, even by EE Times standards
On Thu, 6 Jul 2017 09:45:13 -0400, Phil Hobbs

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So if we want to express temperatures more accurately in degrees
Celsius, just add one decimal digit to the right of the decimal
point:-)

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The accuracy of forecasted temperatures is very bad compared to the
actual measured temperatures, so why would a finer scale help ?

If I understood correctly, the US forecasts talk about low 60s and so
on, thus a range of 5 F or 2 C.  

In practice, when you drive from one suburb to an other suburb or from
suburb to city center, the car outdoor thermometer shows similar size
variations, so what is the actual temperature for a city or small
area?


Re: really idiotic, even by EE Times standards
On 07/06/2017 10:57 AM, snipped-for-privacy@downunder.com wrote:
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Yeah, good luck getting the weatherman to do that, or your digital
thermometer--have you ever seen one that had more significant figures in
Celsius?

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It helps rhetorically a great deal, as I pointed out elsethread,   I
have a wireless digital thermometer on my house.  Three digits either
way, meaning that it's easier to estimate rates of change accurately.

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You folks are just making apologies for an inferior scale, at least for
rhetorical purposes.  You like it, that's fine, but let's leave off with
the idiotic condescension, as though anything European is automatically
better.  That's the sort of crap you folks accuse _us_ of.

Cheers

Phil Hobbs

--  
Dr Philip C D Hobbs
Principal Consultant
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Re: really idiotic, even by EE Times standards
On Thursday, July 6, 2017 at 11:24:39 AM UTC-4, Phil Hobbs wrote:
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Wow, Phil, seems like someone hit a sensitive spot.  For weather I like  
degree's F.  Mostly 'cause that's what I grew up with.  Personally I'd  
like to see more use of the Kelvin scale.  It gets rid of silly numbers  
like -452 F.  It's 300.5 K in my office, a touch warm.
 (AC is being repaired.)      

George H.  
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Re: really idiotic, even by EE Times standards
On Thu, 6 Jul 2017 11:24:28 -0400, Phil Hobbs

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In Finland, the minimum and maximum temperatures are reported with one
decimal in weather reports. I have several digital in/outdoor
thermometers with 0.1 C resolution. Of course, display resolution is
different from accuracy.

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A three digit Celsius thermometer would have the range -99.9 to +99.9C
which would be enough for most everyday situation, except perhaps in a
sauna, when some prefer over +100 C low humidity temperatures.  
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It is not a question of US vs. Europe, it is a question of US vs. the
rest of the world. This doesn't apply only to temperature measurements
but to quite a lot of other measurements.  
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Re: really idiotic, even by EE Times standards
Phil Hobbs wrote on 7/6/2017 11:24 AM:
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The problem is the opposite.  Temperature is hard to measure accurately  
without calibration of each thermometer.  When you set your thermostat to a  
tenth of a degree Celsius that is 100% vapor.  1 degree Fahrenheit is beyond  
the accuracy of most devices.  1 degree Celsius is about the limit of  
accuracy without calibration or spending more bucks so finer measurement  
would seem to be pointless.  However, a degree Celsius is also a bit coarse  
for a home thermostat.  I often will tweak my thermostat 1 degree  
Fahrenheit.  Half a degree Celsius would be needed I think.


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I lost track of who is saying which is inferior.  I think it's six of one  
and half dozen of another.  To some each is preferable.

--  

Rick C

Re: really idiotic, even by EE Times standards
On Thursday, July 6, 2017 at 11:24:39 AM UTC-4, Phil Hobbs wrote:

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 t
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I am  not sure where my comments ought to be placed.  Picking on Phil's pos
t is arbitrary.

But from all the discusion it is obvious that both F and C are not perfect.
  But I am convinced that there are too many temperature scales.

True story.  The receiving inspection for some transistors required  that t
hey pass a 100 %  inspection that they were good after being heated to 125  
C.  The engineer writing the procedure was certain that the receiving inspe
ction area would have F thermometers.  So he converted the 125 C to F.  But
 the receiving inspection area only had C thermometers.  The tech doing the
 inspection  set the oven to the number in the procedure  257.  And that lo
t of transistors were cooked at 257  C.  So there is a reason to only have  
one temperature scale.  This was back in about 1960  when a thousand transi
stors cost about $5000.

I would like it because I have a good memory for numbers and remember thing
s things like copper melts at about 1200 degrees.  But is that C or F.

I personally would like a scale that has 0 as being about the freezing poin
t of water and 100 is about body temperature.

Currently I have a cheap Chinese humidity and temperature gauge in the base
ment.
It will display either C or F temperatures.  But it is obvious that it calc
ulates the C temperature from a sensor and then converts it to F.  So when  
it is set to C it goes up one degree at a time.  when it is set to F it goe
s up by one or two degrees at a time.  So in this case F does not have more
 resolution than C.

                                           Dan

Re: really idiotic, even by EE Times standards
On Sat, 8 Jul 2017 05:41:47 -0700 (PDT), " snipped-for-privacy@krl.org"

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Yeah, like we have too many deodorant brands on the shelf.
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There is also good reason to hire employees with half a brain and
provide them an ounce of training.

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Strange.  When I remember things like this, I remember it as a
temperature, not a number.  The units are part of the deal.

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Not sure why that would be better but it would make Phil happy (more
resolution). ;-)

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No, that thermometer has a fixed resolution.  The resolution of the
units hasn't changed.

Re: really idiotic, even by EE Times standards
On Sat, 8 Jul 2017 05:41:47 -0700 (PDT), " snipped-for-privacy@krl.org"


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What do you understand by body temperature ?  

Is it the human _core_ temperature of slightly below 37 C or the human
_skin_ temperature of about 30-31 C ?

After about 30 C, you can't get away with internally generated heat
(about 100 W) without evaporating cooling (sweating).  

Of course, a civilized white man tries to avoid sweating. Thus the air
conditioning should be able to keep the temperature at tolerable
levels.


To bring this discussion somewhat towards on topic, think about the
human as  a transistor on heatsink. The human core temperature is
equivalent to junction temperature and skin temperature equivalent to
heatsink temperature and the human body as thermal resistance Rjh.

Evaporation cooling was sometimes used with big (100 kW+) transmitting
tubes. Unfortunately silicon devices are more or less useless for
evaporation cooling, but some new semiconductor materials could be
used to evaporate water and hence get rid of excess heat.


Re: really idiotic, even by EE Times standards
snipped-for-privacy@krl.org wrote on 7/8/2017 8:41 AM:
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If they change the standard (albeit arbitrary) scale to something closer to  
Fahrenheit it would bollocks up many equations requiring new values for a  
number of important constants.  Do we really want to do that?

--  

Rick C

Re: really idiotic, even by EE Times standards
On Thu, 6 Jul 2017 08:06:44 +0100, Martin Brown

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How many European and Russian spacecraft have landed on Mars?


--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


Re: really idiotic, even by EE Times standards
John Larkin wrote on 7/6/2017 10:50 AM:
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How many spacecraft have failed to land on Mars because of munged unit  
conversions?

--  

Rick C

really idiotic, even by EE Times standards
Pretty idiotic, yup. Their "advanced technology editor" doesn't appear to know anything about SI, as he says that "the kelvin will be replaced by the SI." in other words he thinks that "SI" is the name of a new unit.  

The actual science is potentially pretty interesting. The usual way to do that measurement is with four wires and two FET amplifiers with their outputs cross-correlated. I gather that there's more going on in this scheme.    

Cheers

Phil Hobbs

Re: really idiotic, even by EE Times standards
On Tuesday, July 4, 2017 at 4:43:29 AM UTC-7, snipped-for-privacy@gmail.com wrote:
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Another  odd thing is, this can only be as stable as the resistor value; you need to use both the
resistance AND Boltzmann's constant to produce the temperature.

So, why is the test resistance value independent of age, oxidation, strain, and local magnetic
field?

Then, of course, the bandwidth of the Johnson noise measurement is critical to getting
a good determination: what exactly is the character of the bandpass on that
measurement?   The NIST says  
<http://ws680.nist.gov/publication/get_pdf.cfm?pub_id90%1450>
they use a Josephson junction (AC) accurate V reference and
DSP determination, differentially,  to eliminate dependence on component values.  

So, this is about a way to get (in a calibration lab) a lineup of exotic devices
(including superconducting Josephson junction) and potentially
add to the triple-point of water a dozen other known-temperature stations
at different temperatures.   There'd be a regular recalibration against
that water triple-point, I suppose, for the sense resistors.

The test jig is amusing: the resistor is a four-wire device, with two leads being normal,
and the other two having controlled-impedance to the external connector.   it's
similar to a Kelvin resistor, but with an extra design goal.

Re: really idiotic, even by EE Times standards
On Tuesday, July 4, 2017 at 5:29:49 PM UTC-4, whit3rd wrote:
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I didn't read your link, I assume this is the same Nist group that has  
been working on this for a while.  I read previously that they have  
some multipole low pass. (7,9,11? I can't recall) and a lot of the  
work is getting a good model of the filter...  
(probably temperature dependent :^)    

George H.    
The NIST says  
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Re: really idiotic, even by EE Times standards
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appear to know anything about SI, as he says that "the kelvin will be
replaced by the SI." in other words he thinks that "SI" is the name of
a new unit.

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to do that measurement is with four wires and two FET amplifiers with
their outputs cross-correlated. I gather that there's more going on in
this scheme.

 What they should have said is (probably true) that in the near future
 the K is no longer defined in terms of the triple point of water.
 Just like the seconds has been redefined several times.

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Groetjes Albert
--  
Albert van der Horst, UTRECHT,THE NETHERLANDS
Economic growth -- being exponential -- ultimately falters.
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Re: really idiotic, even by EE Times standards
Hello!


nit conversion app that I'm releasing a new version of, and I thought I'd s
ee if people around here would like to test it.








(but don't, it make them mad).


.com/apps/testing/appinventor.ai_RoyceGrey.Frank_Harr_s_Conversion_App


Re: really idiotic, even by EE Times standards
On Sun, 9 Jul 2017 11:02:13 -0700 (PDT), snipped-for-privacy@yahoo.com wrote:

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Sure. And you can test mine.

https://www.dropbox.com/s/06fdb5g0sc3c1ag/U.EXE?dl=1

https://www.dropbox.com/s/rrpq0bnq6v4gogl/U.TXT?dl=1

I need to add temperature and RTD stuff, some day.


--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


Re: really idiotic, even by EE Times standards
snipped-for-privacy@yahoo.com wrote on 7/9/2017 2:02 PM:
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Your link has a double period, but I can't get it to take me to a useful  
page even when I fix that.  Google wants me to sign up and/or log in.  Can  
you post this somewhere that I can get to it?

BTW, conversions are nice, but better in the context of a calculator.  
Excalibur is an RPN calculator with a  number of conversions built in and  
you can add your own as it is a programmable calculator.  But with a 1920  
wide laptop screen the buttons and text are too small to be easy to use  
anymore.  I'm thinking of rolling my own using Win32Forth.

--  

Rick C

Re: really idiotic, even by EE Times standards
If you go back to the original, there isn't the double-dot.

As for calculators etc. . . well I did the best I could.  There is a ratio-converting feature I'm rather fond of, but I get it.  Thank you for your attention.

https://play.google.com/apps/testing/appinventor.ai_RoyceGrey.Frank_Harr_s_Conversion_App

On Monday, July 10, 2017 at 9:45:40 AM UTC-5, rickman wrote:
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