Cheap thermometer calibration technique?

Read my previous posts. I Know what it is.

Nice job of being immature again, FUCKING WRONG.

No, it wouldn't because it is four times more expensive, and it's electrical conductivity and its thermal conductivity are not the same, asswipe.

Alumininum is he right medium conduction wise, AND it is the right medium cost wise. The coating on eother would yield the same result so any point you thought you were making is moot.

You need to get off you "f*ck with dark matter" high horse, and get back to reality, boy.

The KeithTard, and the Grisetard can't f*ck with me, so what makes you think you can, dipshit?

absolutely the wrong choice though. It is unstable, and gives off vapors, throwing off surface conditions, which is what an imager MUST focus on to get reliable calibration data.

Why do you even bother reading his posts? He is wrong far more often than right and never admits an error.

Actually, the international standard is a bunch ice covered in water a stirred well. The standard clearly says that this must be done in your own coffee cup and the stirring must be done with a plastic coffee stirrer. You have to stir it up while standing in the company kitchen and then measure as soon as you are done stirring. You can't stop to answer the "What the heck are you doing?" question from the cute accountant.

Did you miss the word "almost"? 3rd line, 2nd word in my paragraph above.

With an imager, it takes a few seconds to test a surface to get a pretty good idea of its emissivity. The whiteboard marker, and the water, and the ice cube, all passed my tests for "so black that it doesn't matter", or, equivalently, "almost 1.0"

I read it; you didn't.

John

Ok, he is AlwaysWrong. But when a sensible person asks a sensible question, and the GreatBlunderer gives him advice that is flat preposterous, he ought to be corrected.

John

Both are about 2:1 better than aluminum. The factor is even higher compared to common aluminum alloys; hardly anybody wants to machine pure aluminum, and the alloying wrecks both the electrical and thermal conductivity.

You f*ck with yourself. Or job is to laugh.

John

Yes, I can see your point.

Perhaps someone as a service to the public could write a little bot that puts a follow up on his posts pointing his out.

On May 9, 7:56 am, John Larkin [......]

In all metals, the thermal and electrical conductivity track each other quite nicely. Copper alloys such as brass are way less conductive. The atomic clock folks use a copper alloy that is very resistive to make heaters.

The "expert source" I'm referring to is the document you pointed to several times.

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Please reply in the news group

ith

True. But this may not be the last temperature measurement he'll ever make.

-- John

So, you need a "Garbage bot"? ;-)

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Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
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Michael A. Terrell
Central Florida

Hhat can I say but WrongAgain?

Look into a mirror that's reflecting the sky into your eyes. You see the color of the sky. Now take off your glasses or equivalent to defocus the scene. You still see the color of the sky.

If defocussing means you are averaging unwanted objects into the image with the desired target, sure you need to focus. But no amount of focussing, from any distance, will make the emissivity of shiny copper any better, or improve the temperature measuring accurscy.

If you poke the germanium lens one inch away from the copper, and focus perfectly, you'll be measuring mostly the reflection, namely the temperature of the lens itself, not the temp of the copper. Try it.

OK, common sense: look in a mirror. You see your face, not the mirror. Get closer; you still see your face, not the mirror.

Try it.

John

OK, positively the last time:

IF THE EMISSIVITY IS 0.98, IT CAN'T BE REFLECTIVE IN THE THERMAL IR.

And while you're at it, check your own link for the emissivity of glass. And smooth ice.

John

Most pure metals run right around 150,000 k/w per ohm. Brass seems to be higher, something like 250,000.

John

I mentioned the flat side because I wanted the sensors to be close to, and so at the same temperature, as the surface. The fins could easily be at a different average temperature.

Thanks for the interesting link. I note that it shows a very common, inexpensive material, black cloth, with an uncommonly high emissivity:

0.98. With this information, I'd change my suggestion to using a flattish copper block (highest possible thermal conductivity) of a size to take up the viewing area of the IR meter, holes and sensors as before, and with a piece of black cloth glued to the surface. I think the whole thing would be inexpensive and fairly accurate.

-- John

Was someone talking to you, asswipe?

Then go get yourself looked at, retard.