On Mon, 8 May 2017 10:00:00 -0400, Ralph Mowery
wrote:
I don't know how well they would work for electronic testing, but you
can get them on ebay for about $ 10 and up. Most have laser pointers on
them, but for close in work the laser does not point to exectally the
heat source.
There are other things to look for. There are two common viewing
angles. 8:1 and 12:1. That means at 8 inches distance, the spot size
is 1 inch. There's usually a chart on the side of the thermometer
showing the spot size at various distances. You can see a smaller
spot, at a longer distance with 12:1. Although the only real
difference is calibration and the lens, prices on 12:1 are much higher
than the more common 8:1. There are also some pocket IR thermometers
with 6:1, which I consider almost useless.
The problem with using these to troubleshoot electronics is that
there's no way you can isolate a fairly small component with a large
spot size. You end up measuring the temperature of everything around
it. If you're looking for a hot component, you'll do better with a
cheap thermistor probe into a DVM. It does work well for large
components, like power transistors, heat sinks, xformers, big
electrolytics, etc. I just used mine to isolate the area on the case
of an overheating ASUS RT-N66U. Works well on the large case area.
Also, watch out for the operating temperature range. I like to use
mine for cooking, measuring soldering iron tip temp, automobile engine
temp, exhaust manifold temp, and wood burner temp.
I bought 3 of these a few weeks ago after my Sears IR thermometer self
destructed.
http://www.ebay.com/itm/222404502261
The picture shows the backlighting display changing from
green-blue-red with setpoints. This is NOT included in the model 981C
but is a feature of the 981D, which seems to be unavailable.
Like all such cheap devices, the laser pointer is misaligned. One
thing I like about it is that it does NOT have a rubberized paint
coating on the handle, and will therefore not self destruct like the
Sears version, where the rubberized paint turned to sticky goo.
When not measuring temperature, it's also useful for playing with the
cat, who likes to chase the red dot.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558