Thread: new toy a laser thermometer

dont forget to carry some matt black paint or to make up a ready reckoner for the emessivity settings.

Originally Posted by Blknight.aus

dont forget to carry some matt black paint or to make up a ready reckoner for the emessivity settings.

Now you've got me , I'll be forced to google that big word.

Emissivity depends on factors such as [ame="http://en.wikipedia.org/wiki/Temperature"]Temperature - Wikipedia, the free encyclopedia[/ame], emission [ame="http://en.wikipedia.org/wiki/Angle"]Angle - Wikipedia, the free encyclopedia[/ame], and [ame="http://en.wikipedia.org/wiki/Wavelength"]Wavelength - Wikipedia, the free encyclopedia[/ame]. A typical [ame="http://en.wikipedia.org/wiki/Physical_chemistry"]Physical chemistry - Wikipedia, the free encyclopedia[/ame] assumption is that a surface's spectral emissivity and [ame="http://en.wikipedia.org/wiki/Absorbance"]Absorbance - Wikipedia, the free encyclopedia[/ame] do not depend on wavelength, so that the emissivity is a constant. This is known as the "gray body assumption".
Although it is common to discuss the "emissivity of a material" (such as the emissivity of highly polished silver), the emissivity of a material does in general depend on its thickness. The emissivities quoted for materials are for samples of infinite thickness (which, in practice, means samples which are [ame="http://en.wikipedia.org/wiki/Optical_depth"]Optical depth - Wikipedia, the free encyclopedia[/ame]) — thinner samples of material will have reduced emissivity.
When dealing with non-black surfaces, the deviations from ideal black body behavior are determined by both the [ame="http://en.wikipedia.org/wiki/Geometry"]Geometry - Wikipedia, the free encyclopedia[/ame] structure and the [ame="http://en.wikipedia.org/wiki/Chemical_compound"]Chemical compound - Wikipedia, the free encyclopedia[/ame], and follow [ame="http://en.wikipedia.org/wiki/Kirchhoff%27s_law_of_thermal_radiation"]Kirchhoff's law of thermal radiation - Wikipedia, the free encyclopedia[/ame]: emissivity equals [ame="http://en.wikipedia.org/wiki/Absorbance"]Absorbance - Wikipedia, the free encyclopedia[/ame] (for an object in thermal equilibrium), so that an object that does not [ame="http://en.wikipedia.org/wiki/Absorption_%28optics%29"]Absorption (electromagnetic radiation) - Wikipedia, the free encyclopedia[/ame] all incident light will also emit less radiation than an ideal black body.
Most emissivities found in handbooks and on websites of many infrared imaging and temperature sensor companies are the type discussed here, total emissivity. However, the distinction needs to be made that the wavelength-dependent or spectral emissivity is the more significant parameter to be used when one is seeking an emissivity correction for a temperature measurement device.
Thus, it is important to understand the distinction between total and spectral emissivity and where they apply.

^^^ You have too much time on your hands

and probably hasnt read the manual for his hand held temp gun.

Originally Posted by Blknight.aus

and probably hasnt read the manual for his hand held temp gun.

Was there a manual? I just looked in the box and there was a small leaflet I unfolded it and there was and in English too. And what you mentioned about masking tape or black paint.

Originally Posted by spudboy

^^^ You have too much time on your hands

Yeah! Like Spudboy says. Are you sure you drive a Land Rover, shouldn't you be fixing something instead of doing all that weird stuff?? What next?? " It's probe time!"

Next time you are or more the point your good lady is baking with the oven any chance of comparing oven temp to food temp for me please????
I have just invested in an outdoor wood fired oven,from results with cooking sofar it cooks hotter than the temp gauges read.One of these things would be ideal Im thinking .
Andrew

For the cost it's probably a good tool for a guide to if you have hot spots etc, the scanner I have cost around $700 and has adjustments for emissivity settings...... so I don't need to graffiti everything with matt black spray........ But for scanning around the block and head, Radiator, trans etc there not too bad