27 Jul
2007
27 Jul
'07
10:25 p.m.
From: Brent Hilpert <hilpert at cs.ubc.ca>
---snip---
BTW: The U-shaped ring is a ring so that after the tube has been vacuummed
&
sealed, it can be inductively heated from the outside (forms a
single-winding
secondary of a transformer) to fire the getter. If you look at a variety of
tubes the getter splash is on the envelope opposite the ring, be it the top
of
the envelope or somewhere on the side, and the open side of the U faces the
envelope so the getter will fire out onto the envelope rather than the
electrodes. In really old (1920s) tubes the ring was a small cup holding
the
unfired getter instead.
Hi
On really old tubes it was just painted onto the glass pedistal that held
the feed thru's. I have a number of these.
Dwight
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