[volt-nuts] Voltage standard spotted for sale, 4410

[Will]

2014-08-12 1:25 UTC+03.00, Tom Knox <actast at hotmail.com>:
> I am not sure the use of LM329's was a cost saving measure or compromise,
> actually the 4410 uses a different approch, it's basicly is a big oven.
> Guildline has been a Metrology leader for decades and  has been a leader
> including  temp measurements and oil baths so I for one would be interested
> in how well their approach to a voltage standard performs.

The 4410 was not designed or manufactured by Guildline. Just like many
of the products sold under their brand name.

At the time of design the LTZ1000 was not yet available and the Fluke
ref amp was obviously property of Fluke only. The only same level
technology available to all manufactueres was the 1N829 zener which if
carefully selected and matched can be as good as LTZ1000. Datron
calibrators with multiple selected, aged and matched 1N829 zeners are
a good example of that.

The original 100 page (Statronics) documentation seems to be a masters
thesis rather than a product manual and has a detailed description of
the design process. The text mentions that the 1N829 temperature
compensated zeners were discarded because of the poor availability in
Australia where the unit was developed. The LM399/LM329 series was
selected because it was the "best available". Band-gap type references
were also evaluated but found unsatisfactory at the early stage.