[volt-nuts] HP 3456A AC cal

[MARVIN]

The 3456a is ~20x less accurate than the 3458a in VAC. That's as good as it gets. 

Here's a comparison of all the top DVM as provided in the 1993 HP equipment catalog, 1993 was unique in that it covered many generations of DVM/DMM many of which were soon to be dropped from sale. 

Click or go to the link: 

http://www.imagebam.com/image/f4f16c350823319 

The 3456a shines in DCV. 

A used 34401a typically sells for $300-700, a 3457a ~ $200-400, 3458a ~ $2,000-5000 but a 3456a is ~$70, it offers very good bang for buck in DCV. 

----- Original Message -----

From: "Richard Moore" <richiem5683 at gmail.com> 
To: volt-nuts at febo.com 
Sent: Thursday, September 11, 2014 7:30:26 PM 
Subject: [volt-nuts] HP 3456A AC cal 

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.... 
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