"Russ" bravely wrote to "All" (22 Apr 05 06:56:36)
--- on the heady topic of " Temp probe for troubleshooting"

Ru From: "Russ"
Ru Xref: aeinews sci.electronics.repair:46218

Ru A few times the finger thing worked real well for me. One was a
Ru pinball transistor It was so hot it burned my finger. I guess I was
Ru wondering if something more sensitive would be helpfull.

A wax crayon... Wax melts just under the boiling point of water around
180-200'F. IIRC there are even special wax mixtures calibrated for
specific temperatures. These are used to calibrate furnaces, ovens,
etc.

Many ceramic capacitors are highly sensitive to radiant heat and their
capacitance value will drift according to temperature. When used in a
bridge or a counter even the heat from a hand can be readily detected.

IR diodes are also sensitive to radiant heat but have to be compared
to a known temperature.

A*s*i*m*o*v

.... 'Keep the smoke inside.' -- 1st Rule of Electronics.