From what I remember: The 3455A has a good AC front end but is a real pain to calibrate with a lot of adjustment (read flexibility). I think HP gave up a lot of accuracy for a simpler calibration. The 3457A seems to do AC a lot better than the 3456A. Nether meter come close to doing what the 3458A does.
On Fri, Sep 12, 2014 at 12:04 AM, M K <[email protected]> wrote: > On 12/09/2014 00:30, Richard Moore wrote: > >> I'm trying to get my head around the AC cal procedure for the HP 3456A -- >> there is no full-scale cal, just some extremely finicky tweaks for the >> bottom ends of three of the four ranges. I really don't understand how this >> is supposed to work, especially since it is very accurate on all DC ranges >> (up to 500V -- above that some heating of the divider R seems to occur and >> it loses accuracy as the voltage increases). But on AC, the tweaks don't >> result in anything like an accurate level reading compare to my 3458A -- at >> 10VAC it is off by hundreds of ppm. Anybody shed any light on this? Is >> there a way to get full scale cal points in AC mode? Any mods to fix this >> -- lovely meter otherwise; I much prefer it to the 34401A I used to have, >> except for the overall bigness.... >> >> Hi Richard, > > Does the meter have a DC to RMS converter chip in it, because if it does > you have to account for the self noise and offset of the gilbert cell at > the heart of the converter. > > _______________________________________________ > 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.
