Cheap thermometer calibration technique?

may

The freezing case works fine with most any tap water to, as I noted,

15mK or better... I have a paper on that somewhere. The important thing is to have a lot of well-crushed ice, preferebly in a thermos, and stir it well. The stainless thermos coffee cups, like you can buy at Starbucks, are fine.

Most IR thermometers are calibrated for an emissivity in the 0.9 sort of area, so may actually indicate a bit below 0 when used with a really good/black source like ice water.

John

may

temp

If you have access to a decent old fashioned mercury thermometer why not just use that to calibrate? Eric

I have used them but the accuracy varies, and with any sensor, it can vary depending on what area its actually contacting. I often need accuracy at 37 C and I use a fast rotating beaker of water, with the reference sensor in the liquid, as close tot the other sensor as posible. I often point the IR gun at a thermostat or digital wall clock/temp to get a quick indication of accuracy.

greg

An IR thermometer will not be very accurate on lower as body temps due to the radiation measured.

An IR is good for above 50 F or 25 C Calibration is best done close to the temps really measured. And yes boiling and freezing water is very accurate and the method with the black body is best.

I noticed that my typical Fluke IR thermometer only works at room temperature. I took it outside last winter, and after the unit starts to cool, forget it.

greg

Have I got really rubbish thermometers? I've tried measuring body temperature both in my mouth and under my arm, and it's never more than about 30C.

--
http://www.petersparrots.com    http://www.insanevideoclips.com   
http://www.petersphotos.com

Basketball analyst: "He dribbles a lot and the opposition doesn\'t like it. In
fact you can see it all over their faces."

snipped-for-privacy@zekfrivolous.com (GregS) wrote in news:gg4b73$4rg$ snipped-for-privacy@usenet01.srv.cis.pitt.edu:

might be a battery problem;their performance often drops with cold temps. (lithium batts are better)

--
Jim Yanik
jyanik
at
kua.net

Anything above absolute zero emits InfraRed radiation.

IR thermometers are calibrated for a very small temperature window, compared to the span of what is available. From low temps to high temps, many models are available. Many operate at a specific wavelength due to spectral windows on their transducers that make the unit very application specific.

A good IR thermometer,correctly factory calibrated, should be left alone, and will remain deadly accurate for years. If one thinks one's reading is off the mark, think about emissivity factor. Do not ever blame your instrument. Operator error is often (nearly always)the case. Calibrated thermo-couples are always nice to have around to verify your IR Thermometer reading capability.

That is, if one buys a reputable instrument to begin with.

Now, if you examine the spec Fluke published, you should find a range of operation, under which it is meant to give a calibrated reading.

The device (IR Transducer) that does the reading (likely a resistor bolometer) is perfectly capable of reading lower, but the electronics it feeds only got designed to work in a specific voltage window, so there will be no read out below a certain threshold. It has to do with Fluke's circuitry and calibrated window of operation. The transducer itself is capable of far more, I guarantee it. Just don't point it at the Sun.

both in my mouth and under my arm, and it's never more than about 30C.

I never thought that I would ever get to say this to anyone and really mean it.

STICK IT UP YER ASS! :-] Hehehehe!

may

Oh boy... a whole tenth of one degree at either end... max.

may

temp

common

Lay it on thick... stir it up good... Haahahah!

both in my mouth and under my arm, and it's never more than about 30C.

And if next time I forgot I'd done that, and stuck it in my mouth?

--

A bloke is in a queue at the Super Market when he notices that the rather dishy blonde behind him has just raised her hand and smiled hello to him. He is rather taken aback that such a looker would be waving to him, and although familiar he can't place where he might know her from, so he says "Sorry, do you know me?" She replies "I maybe mistaken, but I thought you might be the father of one of my children!" His mind shoots back to the one and only time he has been unfaithful, "Christ!" he says "are you that stripogram on my stag night that I shagged on the snooker table in front of all my mates while your mate whipped me with some wet celery and stuck a cucumber up my arse?" "No" she replies, "I'm your son's English Teacher"

Have you ever heard the term, "wash"? And a healthy ass shouldn't have anything harmful in it - it's inside your own body, right?

--
Flap!
The Pig Bladder from Uranus

I think you could survive your own fecal remnant attack. Sheesh. Wash it off already!

But some parts of the body aren't supposed to come into contact with other parts.

Try feeding the exhaust pipe into the air intake in your car and see if you can drive it a fair distance.

--
http://www.petersparrots.com    http://www.insanevideoclips.com   
http://www.petersphotos.com

It said, "Insert disk #3," but only two will fit!

Go on, poke fun at me, what would actually happen?

--
http://www.petersparrots.com    http://www.insanevideoclips.com   
http://www.petersphotos.com

                                                ,cccc,,cccc,

drive it a fair distance.

Bannana in the tailpipe fails as well...

Bwuahahahaha!

If it is a resistor bolometer, one can burn it up by pointing it at the sun.

Some have integrated FETs, and it would blow that... too.