Re: Measuring SMT device temps with Infrared thermometers

On Mon, 27 Mar 2006 08:47:39 -0800, John Larkin
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On Mon, 27 Mar 2006 16:21:14 GMT, Roy L. Fuchs
<roylfuchs@xxxxxxxxxxxxxxxxxxxx> wrote:

On Mon, 27 Mar 2006 08:03:40 -0800, John Larkin
<jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> Gave us:

On Mon, 27 Mar 2006 09:25:13 GMT, Roy L. Fuchs
<roylfuchs@xxxxxxxxxxxxxxxxxxxx> wrote:

On Mon, 27 Mar 2006 01:10:21 GMT, "Bob"
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"EE_user" <EE_user@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:44272d89$0$15851$892e7fe2@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Anyone have any experience with using handheld Infrared thermometers
to measure small SMT devices? I see some devices for $30 and up.

It is possible to adjust for the emissivity differences between
different materials?

What about the ability to focus on a specific device? Like a SOT23?

We have a very expensive infrared camera which is often used to
determine temperatures across an entire circuit board. This is ideal
but inconvenient.

Thanks,


A SOT23 is going to be tough, with the IR units I've seen. The spot size is
a function of how far unit is away. You'd have to be pretty damn close to be
sure you're only picking up the SOT23.

Some have close focus capacity, but not the ones in Mouser or at
Fry's


The more expensive ones have a setting for emissivity, or you can just
calculate what the true reading is (if you know the emissivity of the part
under test).

True.

Or, you can just paint it black (for emissivity=1).

Not true at all. First off it would have to be a matte black, not
glossy, and it will only attain about a .98 emissivity, at best.
Then, there are the conductivity issues which may be a problem when
"painting" a SOT23 package. Most matte black paints have a carbon
based pigmentation.

These guys are the best.

http://www.mikroninfrared.com/Default.htm

Those look nice. Any idea of the price range?


The M-90s are likely a couple grand each.

The MI-N15s are likely half that or less.

The thermal imaging products are much higher.

I don't know exactly. I think they either have a price schedule on
the site, or will send you one, however.

OK, I'll check them out. We usually use a tiny thermocouple (or a
fingertip!) to measure spot temps. It's an imager that I really lust
for.

John

Look through their site a bit. These are the guys that have supported
the electrical power distribution industry for decades.

Have them send you the free DVDs they offer. They really are
enlightening <sic> :-] One of them is power industry specific. The
other is likely process control specific. Like refractory ovens and
such other very high temp items. They even have a couple instruments
pointed at the shuttle launch pads from 1000' away (or did)(now it's
likely an imager). My how time flies.

They had a 4 inch diameter, 26 inch tube, gold mirrored, rifle scoped
and stocked device that most old foggies would remember as the device
they used to examine tower insulators or pole mounted transformers,
keeping them from having to actually climb up to be near them. If an
insulator leaks, as you know, it gets hot.

Now, it appears that all their mirror based tube type reflector
instruments have been replaced with those you currently see on their
site.

K. Irani, the owner, and president (at least he was) IS the inventor
of the resistor bolometer that started this industry back in ... oh...
1960.

Since then, there have been many advances in the industry, as you
know. Their first imager was only 4 frames per second, had a 386 for
processing the image, and was even before they had the capacity to put
it onto a VHS tape. Now, as you can imagine, things are much higher
res, much higher speed, and can be captured in so many ways, it'll
make your head spin.

Other companies which are much larger have even bought their gear in
the early days, and made their own versions (Square D, Raytheon,
etc.), but nothing beats the traceability of these guys' engineering.
They also make the black body sources used by folks like FLIR, etc.
where the entire face of the calibration source has to be as uniform
in temperature as possible, which as you know, is not an easy feat.
Everything is NIST traceable. They even sell a standard NIST
calibrated thermocouple for like $800.

I think they may have partners now as the product line looks much
more advanced than it was back in the mid '80s (FLIR perhaps).

Your desire to have an imager may be cut down by the price of such
gear however. Those babies aren't cheap at all, and they all have to
be bought through sales offices now, instead of directly as was the
case years ago. That means that a chunk of the price is some lucky,
overpaid sales guy's commission. If you can't tell, I have more than
a slight disdain for salesmen.
.

Relevant Pages

  • Re: Measuring SMT device temps with Infrared thermometers
    ... A SOT23 is going to be tough, with the IR units I've seen. ... The more expensive ones have a setting for emissivity, ... First off it would have to be a matte black, ... Any idea of the price range? ...
    (sci.electronics.design)
  • Re: Measuring SMT device temps with Infrared thermometers
    ... A SOT23 is going to be tough, with the IR units I've seen. ... The more expensive ones have a setting for emissivity, ... calculate what the true reading is (if you know the emissivity of the part ... First off it would have to be a matte black, ...
    (sci.electronics.design)
  • Re: Measuring SMT device temps with Infrared thermometers
    ... A SOT23 is going to be tough, with the IR units I've seen. ... The more expensive ones have a setting for emissivity, ... First off it would have to be a matte black, ... Also, painting it will change the way it operates, and alter the data ...
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  • Re: Measuring SMT device temps with Infrared thermometers
    ... A SOT23 is going to be tough, with the IR units I've seen. ... The more expensive ones have a setting for emissivity, ... First off it would have to be a matte black, ... Any idea of the price range? ...
    (sci.electronics.design)
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