Homebrew PCBs

> And what exactly is the advantage compared to the temperature probe on the
> multimeter?
> i mean the whole thing with the emmisivity is not worth the trouble or
not?
> the tiny temperature probe on the mutimeter is on equal temp. in 3
> seconds, it reads
> up to above 1000 degree C (they say 1200, i really doubt that....).

Most multimeter probes are very inaccurate when trying to read a surface
temperature. They are fine for insertion, or for measuring fluid or gas
temps. Surface temperature measurement is a huge problem, IR works some
times, but is not a cure-all either. A differential heat flux sensor may be
the best solution for highly accurate surface measurements, but the
fragility, and cost make them less than practical. One of my coworkers
designed a really decent surface probe, but even it is subject to a small
amount of thermal loading. http://www.fluke.com/products/home.asp?PID=34306

We sold a bunch of these http://www.fluke.com/products/home.asp?PID=9452 and
while good for ball park measurements, they do not come anywhere near the
previous version for surface temps.

Pipes are another challenge, the guys did this one, and due to the
shielding, it does pretty well.
http://www.fluke.com/products/home.asp?PID=9472

Insertion probes do quite well, but you do need to insert them a minimum of
5, and hopefully 10 X the probes diameter to get a good measurement.

As far as 1000 deg C, most probes will not survive very long, or will be
subject to changes in their output after high temp exposure. Many times rare
earth metals are used to protect the probe, and the costs skyrocket. I
bought a type S probe years ago, it was over $1000, vs a generic K probe was
only $7.

We used to build high temp sensors which used IR and could measure thousands
of degrees C, an environment wherein a regular probe would be instantly
vaporized.

I miss the temp sensor days, they were a lot of fun.
Ron