The best way is to read the voltage with a resistor divider of course.
 
Then calculate the ADC values for each voltage
reading over your scale.
 
Pop the temp and ADC readings into a curve fitting
program, and determine a 2nd degree polynomial.
 
I found that 0.1 degree C accuracy with integer math
and an 8bit ADC was quite possible.
 
I use Curve Expert.  Do a search.
-----Original Message-----
From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Ercan Duran
Sent: December 2, 1999 10:39 AM
To: PICLIST@MITVMA.MIT.EDU
Subject: NTC thermistor using...

Hello.
 
I'm trying to use a NTC thermistor with a 16F877 device.
It's a 10K thermistor B Constant 25/50 C(K) = 4100.
If I read resistant of the NTC, how can I calculate temperature in Celcius degree.?
 
Thanks in advance.
 
Ercan DURAN