AVR-Chat

--- In AVR-Chat@yahoogroups.com, Kathy Quinlan <kat-yahoo@k...> wrote:
> Hi all,
> 
> I need to measure tempretures around 36C with the best acuracy I 
can 
> get, I would like to measure with a precision of 0.1C so I guess I 
need 
> acuracy or ~0.05C.
> 

How fast do you need to take the measurements?  In other words, is
the environment changing rapidly.  Many thermocouples have a very
long time constant.  Their thermal mass is still pretty large. For
quick measurements, I use bead thermistors and a small amplifier 
circuit.  You have to watch for self-heating and the resistance 
(gauge + length) of the wire you use to attach the thermistor. But
you can get them with time constants to 0.5 seconds.  With a good
circuit you can get to a hundredth of a degree C.

- ayman