[volt-nuts] Traveling Standards
smither at c-c-i.com
Fri Aug 26 06:07:55 UTC 2011
Thank you so much for the great responses! You have all given me a lot
to think about.
Andreas mentioned the lm339. One candidate I am considering is the
lm119ah. Of the references I have at hand (lm119a, lt1027bcn, and
max6350cpa) the lm119a looks the most promising. Andreas mentioned that
humidity and stress can cause several ppm errors. The lm119a is in a
hermetic to-46 package in a thermal shield - so hopefully those effects
will be minimized. The idea that the orientation matters is a new one
for me. I will be sure to mark "TOP" on the final package.
Fred advised against the use of pots. I agree. I was thinking of just
using the raw reference output. For my purposes, I don't really care
what the voltage is as long as it is stable and can withstand shipping.
Warren - I appreciate the offer of a 1n825, but the TC is too large for
this purpose. I also suspect it will be noisier than the lm119a.
Dick and Charles M. - thanks for offering help with this project! I
will contact you off list for your address when I have a traveling unit
prepared and will welcome your measurements of it.
Charles S. - your understanding is correct - I would ship the unit to
anyone that is willing to measure it for me. You idea of shipping it
powered up deserves some more thought. One concern I had about this was
the added weight of the batteries for shipping. It may be an even trade
against having a transformer / rectifier / capacitor to make the
required power supply level.
Thanks all! Now to do some serious design and construction.
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