Topic: Infrared thermometer gun - page 2. (Read 4188 times)

Meteor fell and killed everyone

...but...but...you still haven't explained why the dinosaurs died  

Ok. I'll explain for you in the best possible way I can. :3 Starting off assuming there's no prior knowledge of physics, just to be clear.

All matter emits radiation when it has thermal energy (heat) in it.

For example. The sun, being super freaking hot, emits all sorts of radiation, and by radiation, I mean electromagnetic radiation. This is what light, radio waves, microwaves, xrays and such are made out of.

But anyways, within what the sun emits, it also emits electromagnetic radiation that is within a range that we call the "visible spectrum", which is basically the types of electromagnetic radiation that what we call "light", ie, what our eyes can see.

The sun shines because of this principle. This is the same principle that makes an iron rod glow red when it is extremely hot.

So, due to this principle, we (our bodies), animals and electronics ALSO glow. Because they are warm. Except they don't glow in the visible spectrum. They glow in a different kind of light, a type that we can't see with our eyes. This light is called infrared light. It's like red light, except it's more red than red light, in a sense.  So much that it's not visible to our eyes anymore.

Your infrared temperature meter works by exploiting this principle. It measures how much infrared light it is picking up from wherever it's pointed at, and does math within it's internal electronics, and gives you a temperature.

But anyways. Now that you understand this concept, you can understand why not to point it at metallic surfaces.

In the same way that cellphones don't work well in elevators, due to the metal walls, or in the same way that you can see absolutely nothing through a sheet of tin foil, no matter how thin it is, the infrared temperature gun will not be able to get a correct temperature reading if you point it at metal, because the metal will be reflecting infrared light from somewhere else. Such as your hand.

I know this was an overkill explanation, but perhaps you or someone else will enjoy not only knowing why, but understanding why. :3

Noted, thanks.

Yeah, just get a proper one and your good to go. I can recommend Testo 830 series with an additional surface probe for extreme accuracy if needed.

Avoid all the really cheap ones, they don't have a feature to adjust the emissivity settings (thats like measuring distance by counting steps while running...).

It did
 
Well illustrated here:
So this is one thing I will look for:

Great, thanks guys.

http://www.thermoworks.com/blog/2012/03/infrared-thermometry/

i hope this will help

OK...why is that?

Yup, that's my intention. thinking about checking VRM temps (no software for that in Linux).

I bought this one: http://dx.com/p/1-2-lcd-non-contact-digital-infrared-thermometer-with-laser-sight-50-c-380-c-35754

It's cheap and the readings seem pretty accurate. I can point it on the back of the PCB on my GPUs and it will report a temperature within a degree or two of what the card's internal temp sensor reads.

Has a good temperature range for other stuff as well. Backlit screen and laser pointer, I recommend it

If you've never bought from DX before beware that their stuff can take a while to ship sometimes

don't use it for metallic surfaces

phps you search better for a contact thermometer http://www.onlinecomponents.com/fluke-cnx-t3000.html?p=44434473

So I am thinking about buying one those thermometer guns with a laser pointer for measuring card temps, and probably annoying my cat.
Something like :

Any advice on what to search for, what to avoid...or a good brand maybe?