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Re: small (& large) tube filling pressures
Oke Tom, here we g0,
Below I produce the backfilling pressure list for 10 mm tubing in feet and Torr.
Now you can calculate the rest by your own.
tubediam in mm tubelength in foot Hgas+Hg Neon
10 0.8 - 1.3 20 24
1.3 - 2 15 19
2 - 4 12 15
> = 4 10 12
One (1) meter is 3.2 feet and when you multiply the Torr backfilling pressure
with 1.33 you have the tabel in mbar again.
Make sure that using this list every glastube has the electrical length of the
last mentioned length of the list. So, in the above published list the tube with
a length of 1.3 feet is electrically seen 4 feet long. Keep that in mind when
you are using fi Kenny's
software for calculating transformer loading.
Reply to Jeff:
The reason that we backfill neongas to (at?) a higher level then Ar+Hg lies in
the fact that than the ignition voltage is lower (because of the more atoms) so
that the neontubes ignite or reignite (to your mains 120 times a second)
earlier, so shorter (earlier) after the tension is zero crossing. Proper tubes
reignite about 10 degrees after zero crossing and that's the reason we backfill
neongas to a higher level then Ar+Hg.
The tubes have a more stable light output, without flickering or other visible
diseffects, in a straight discharge line (flow?)
The disadvantage of higher backfilling pressures is that the Ri of the tube will
be higher, so you must do a proper loading to your transformer with a mA meter.
As I think that that's essential for every sign or transformer section it will
give you no extra work.
Hope that you appreciate my European input, is signing with
Best regards
dirk a. boonstra.
PS. arturo de carlo is the owner of the computer I'am playing with, so he always
is mentioned as the sender to the net.