> In fact, it's 0.05 / 273 C (or so). 0 C is a rather arbitrary reference.
> 0.05/273 is 0.02% precision.

That is extremely high precision.
1:5000 or about 12 to 13 bits accuracy.

You can buy some extremely high precision thermistors, althouh cost may be > 
inexpensive.

Platinum PT100 resistor temperature sensors can be had at as good as 0.001C 
at 0C.
Here mentions      0.15, 0.03 and 0.001 C accuracy at 0C.

    http://www.picotech.com/pt100_sensors.html

Measuring the related paramers (voltage, current) at that accuracy is going 
to be challenging.
16 bit voltage accuracy is "easily achievable" off the spec sheet and 
sometimes 'interesting' in real life.

FWIW the probes above cost about $US50 for +/- 0.15C and about $US100 for 
+/- 0.03C ratings.

_________________________

Exceptional care using the delta I / delta V diode method will allow very 
good accuracy with 'any old' silicon diode.



            Russell



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