Pro/Forums - View Single Post - Water block Writeup with the big dogs!!!!

pHaestus · 08-09-2002, 11:58 PM

Scan up a bit; some comments on uncertainty from me. And I think that the uncertainty is better described by the square root of the sum of squares. Assume +/- 1C for both the diode and the reader, or sqrt 2 for the uncertainty (1.4C) . Two temps need to be about 3C apart to have any confidence that they actually different, eh?

Or with compunurses, the water temp and "CPU" temp would be +/-3C. So sqrt 18 = 4.2C

This is a simplification of the error propogation of course and as #rotor mentioned you can do some stats to make use of large sample populations and lower this somewhat. By and large, though you are doomed if you are looking for subtle temp differences with such gear.

08-09-2002, 11:58 PM	#84
pHaestus Big Player Making Big Money Join Date: Aug 2001 Location: irc.lostgeek.com #procooling.com Posts: 4,782	Scan up a bit; some comments on uncertainty from me. And I think that the uncertainty is better described by the square root of the sum of squares. Assume +/- 1C for both the diode and the reader, or sqrt 2 for the uncertainty (1.4C) . Two temps need to be about 3C apart to have any confidence that they actually different, eh? Or with compunurses, the water temp and "CPU" temp would be +/-3C. So sqrt 18 = 4.2C This is a simplification of the error propogation of course and as #rotor mentioned you can do some stats to make use of large sample populations and lower this somewhat. By and large, though you are doomed if you are looking for subtle temp differences with such gear.