Mark Sims wrote: > My favorite temperature measuring system is the AD537 voltage to frequency > converter. It has an on-chip temp sensor or it can be used with an external > thermistor. The chip is usually found in a TO5 can, so the on-chip sensor > has a fairly high thermal mass. Thermistors can provide a near instantaneous > response if you use a small enough device (you can get thermistors that are > nearly microscopic in size). You can easily get microdegree resolution with > hardware any time nut has. > > The biggest problem is calibrating it if you need absolute accuracy. You > could do a comparison with the 2804A. Or a three point calibration at the > triple points of ice and gallium along with boiling water (compensated for > air prerssure, etc)... but then triple point cells are not in most pepole's > bag 'o tricks... > > You could always compare it with a Johnson noise thermometer. No triple point cells etc are required, just a large thermal mass the temperature of which can be varied with good short term temperature stability.
Thermistors are highly nonlinear and it is advisable to use more than just a pair of accurately known temperatures to calibrate them. Bruce _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
