I've been looking at the various voltage reference schemes used in HP's 345x line of DMMs. I was intrigued by the use of a Peltier chamber to control the temperature of the reference element in the HP 3450A DMM. I looked in the service manual for that unit, but I couldn't find a good picture of the reference assembly. Would anyone having a 3450A be adventurous enough to pull it apart enough to take a few good pictures of the innards? I found a Sales Amplifier paper from HP that roughly describes the reference assembly, but no good pictures. I'm wondering if the diode under test and a thermistor should be mounted directly to the surface of the Peltier device or to a copper or aluminum interface between the Peltier and the thermistor & diode. Any thoughts? How did HP do it in the 3450A chamber? I have a number of 1N825 and 1N827 diodes that I'd like to toy with. In particular, I'd like to build such a Peltier controlled chamber to ease the task of finding the zero tempco spot on the zeners.
Dave M _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
