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Re: small tube filling pressures
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From: INTERNET:EclectiKat@aol.com, INTERNET:EclectiKat@aol.com
TO: arturo de carlo, 101550,350
DATE: 4/17/96 12:53 AM
RE: Re: small tube filling pressures
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Date: Wed, 17 Apr 1996 00:44:42 -0400
Message-ID: <960417004440_377003832@mail06>
To: 101550.350@compuserve.com
Subject: Re: small tube filling pressures
Fascinating list,
I see several things right offhand without study.
1. Our lists never make a distinction in fill pressures between Ar and Ne
pressures, which I have always found suspicious.
2.And when I have seen variations in pressure with tube length, it is always
for Ne only, never for Ar.
3. We (I?) have more uses for fill pressures below 10mm than for pressures
Is that approximately correct? Yes Jeff. (DAB)
I forgot to mention one very important thing about the list with the backfilling pressure's, so I reply myself.
The fact that the short tubes are filled to a higher pressure is not only for the volume of gas that you need for a long lifetime.
Another thing is that we want to have the Ri (internal resistance) of the tubes so close to each other as possible.
One can do that as he is making all the tubes from the same length, but we all know that that is impossible.
Therefore we backfill the short ones to a relative higher pressure, not only for its lifetime, but to make sure that they are electrical seen from the same length, even when they are halve the length compared with the longest one.
By adjusting the backfilling pressure you can make a 1 foot tube as long as a 5 foot tube.
Doing this you can be sure that both tubes are igniting at the same time and you are prevending that the short tube must wait, while it is ionized by the tension, but there is no current floating, to (on) its 5 times longer brother.
As we know there is (in your mains) a reignition 120 times every second, and installing tubes with a very great difference in length will always give trouble.
The shortest one will always be blown out after a while as there is that enormous high flash with the magnetic field over it.
One can compare it with two bulbs of 110 volt connected in series to a 220 volt mains. Only meassuring the R of the bulbs you can calculate which one will be burn out first as Mr Ohm knew that already.
Looking to the table one can see that the amount of gas is nearly the same for each tube, therefore short tubes are backfilled higher.
Resume: short tubes are filled with a higher pressure to make them "electrical seen longer", for the purpose of lifetime, and to prevent that the lectrodes are falling of.
Best to you all,
wished to you from dirk a. boonstra