Per my conversation with Gary Biermann, the 4 ppm and the 2 ppm units are the same as the 8 ppm units except they perform better. Purely a selection of best performers and nothing to do with a special circuit.
I don't know about Fluke. Joe -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of John Phillips Sent: Tuesday, October 30, 2012 11:07 AM To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] (New to me) 3458A Trivia I think the main thing they do is age and screen. On Tue, Oct 30, 2012 at 6:48 AM, Bill Gold <[email protected]> wrote: > Speaking of the 03458-66529 reference board added to the HP 3458A by > Fluke (before Fluke offered the 8508A), has anyone ever seen a > schematic of that board or how Fluke could rate that reference at 2 > ppm? One person on this forum theorized that by lowering the > operating temperature of the LTZ1000A to around 70 degrees C, which is > what the LTC device specification note recommends, this might have > what was done to achieve the better drift specification. It was noted > that HP was running the LTZ1000A at around 105 degrees C which might > accelerate the aging rate. I lowered my references to around 70 C and > they have seemed to be a little more stable when checked against the > Fluke 732A DC Reference Standard. But I never started a project to > follow up on this theory. Just another project to play with when I "get a round toit" > Bill > _______________________________________________ > 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. > -- John Phillips _______________________________________________ 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. _______________________________________________ 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.
