really idiotic, even by EE Times standards

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.

Reply to
George Herold
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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.

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.

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.

Reply to
upsidedown

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.

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.

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Rick C
Reply to
rickman

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.

Reply to
whit3rd

John Larkin wrote on 7/6/2017 10:50 AM:

How many spacecraft have failed to land on Mars because of munged unit conversions?

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Rick C
Reply to
rickman

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.

Reply to
whit3rd

So they aren't very good at selling ad space, are they?

Maybe those guys can read? ;-)

Reply to
krw

It's funny how you throw away the units digit and then talk about resolution. Really all you're saying is that the reliable resolution of weather forecasts is closer to 10F than to 10C (or to 1F or 1C, for that matter).

The reliable resolution of a weather forecast is hardly a sensible way to choose a measurement standard.

Clifford Heath.

Reply to
Clifford Heath

We use all sorts of archaic units in everyday life. Pounds, cups, tablespoons, fluid ounces and pints and gallons, tons, inches and feet and yards and miles, horsepower, proof, ounce-inches, carats, drops, fun stuff like that.

In engineering, we mostly use SI units, the exception being PCB layout and mechanical design in (mostly) decimal inches. Fans are usually evaluated in CFM.

Some of my aerospace customers still use lbs, lbf, inches, slugs, degrees F, PSI, foot-pounds, all that to do serious engineering calcs. That seems clumsy to me.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

I think that is a pretty good way to choose the temperature standard used in weather forecasts.

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Rick C
Reply to
rickman

All of our PCBs and mechanical designs are SI but that probably goes along with "Reference Designator, Amateur".

That's what computers are for.

Reply to
krw

t

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

Reply to
dcaster

Yeah, like we have too many deodorant brands on the shelf.

There is also good reason to hire employees with half a brain and provide them an ounce of training.

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

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

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

Reply to
krw

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.

Reply to
upsidedown

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

Reply to
RoyceGrey

Sure. And you can test mine.

formatting link

formatting link

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

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

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?

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Rick C
Reply to
rickman

snipped-for-privacy@yahoo.com wrote on 7/9/2017 2:02 PM:

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.

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Rick C
Reply to
rickman

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.

formatting link
snipped-for-privacy@yahoo.com wrote on 7/9/2017 2:02 PM:

Reply to
RoyceGrey

snipped-for-privacy@yahoo.com wrote on 7/14/2017 3:43 AM:

I don't know what you mean "original". I replied to your post of July 9,

2:02 PM my time. That post has two periods between the google and the com. Either way, as I mentioned, Google requires you to have an account and log in to view the material.

I don't know what you produced. I couldn't view it.

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Rick C
Reply to
rickman

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