>> Rich said:
>Are Au and Mo notable emitters?
>Can the grid of a tube with a hard vacuum reach high
>temperatures if
>no current is passing through it?
>If zirconium has to be at 1400ºC (Terman) in order to
>absorb oxygen
>and nitrogen, how can a 3-500Z's anode getter air
>molecules?
Will said:
>One needs to study how tubes are constructed to see what
>may happen. The metals used in them were picked
>over their high heat qualities (wouldn't melt). The plating
>had to do with emission of electrons.
>Yes, I seen a reference earlier about the 3-500Z having a
>getter of zirconium. For it to work, it's optimum temp is
>1400 deg C and is what it's ran at in this application. In
>that case, the anode would be white hot (the welding color
>of steel). There's some other problems with this too, but I
>won't >go into them here (IE Hydrogen gas). If one actually
>wanted to make this work, it looks like a tantulum anode
>would have been a better choice.
Hi Will,
Rather than you and Rich make wild guesses about gettering
in a 3-500Z, why not give Eimac a call and ask them what the
gettering material was in a 3-500Z? If Paul Larson still
works there (last time I talked to him about getters was
about 10 years ago) you might ask him.
By the way, Terman on page 187 of my Third edition warns
about excessive resistance in grid leads. Terman states, "
If the resistance in the grid circuit is high enough, this
process can become cumulative, resulting in the control grid
potential suddenly becoming positive and causing the
**destruction** of the tube as a result of excessive plate
current."
I can't find a thing in Terman that supports your or Rich's
claims. As a matter of fact everything I do find seems to
disagrees with your theories.
I'll scan that page of Terman and put it up on the web page
in a few minutes if you like.
73 Tom
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