"Jim Wilkins" wrote in message
news
"Garrett Fulton" wrote in message
...
On Wednesday, May 10, 2017 at 6:40:09 PM UTC-4, Jim Wilkins wrote:
................
However my flea-market 1970's Fluke 4-1/2 and 5-1/2 digit bench
meters
are still within spec when measuring a 10V calibration standard.
-jsw

I've got 3 meters I'd like to check for calibration. Is that 10V
calibration standard something that costs an arm and a leg?

Garrett

https://www.amazon.com/DROK-Precisio.../dp/B00NL419KW
The reference IC is really an AD584.
Its hand-written label indicates that it measured 10.00222V on an
Agilent 34401A at 21C in 2015. My Fluke 8800A (no cal?) shows
10.0017/18, the Fluke 8600A (1995 cal) shows 10.002V.

-jsw

My house is now at 22C so as promised I rechecked theAD584 reference
against the 5-1/2 digit Fluke, after an hour warmup which decreased
the Fluke's initial 11 microVolt zero offset to +/-0.
Using an analog variable power supply, the Fluke reads +10.0018/19
with 12V powering the standard, and +10.0021/22 with 18V powering it.
It starts to droop below 10.0018 at less than 11.0V in.

I'd say that a more convenient 12V A23 battery clipped onto the board
is fine for adjusting 3-1/2 and 4-1/2 digit DVMs and the AD584 only
benefits from two dangling 9V batteries with a 5-1/2 digit meter. Up
to 30V is permitted. At 27V the Fluke still reads +10.0021/22, but
lingers longer on 22.
-jsw