[time-nuts] Environmental sensor recommendations.

[John Green]

Why has no one mentioned thermocouples?
I had some experience with thermistors a few years back designing thermal
attenuators and equalizers for CATV. NTC thermistors can have a large
change of resistance for a unit change in temperature. They aren't linear,
but there are formulas for computing resistance vs temp. PTC thermistors
have a much smaller change per unit change in temp., but are much more
linear. And, they are susceptible to self heating, which makes things
interesting. If I remember correctly, in my research something called an
RTD was supposed to be the king when it came to accuracy and repeatability.
As someone else has stated, the IC devices are supposed to be quite good,
but you have to interface with them.