[Hammarlund] Speaking of Tubes ...

[Kenneth G. Gordon]

On 30 Sep 2014 at 22:55, Guido Santacana wrote:

> What if... Solid state devices had not been invented back in the 50s. Tubes
> would have evolved into ....... Sub sub miniature tubes?

Probably. 

I have always regarded the subminiature tubes first developed during WWII, 
as an extreme example of what COULD be done with tubes.

Lifetimes of 100,000 hours for instance.

So, here are a couple of related questionss for all of you:

1) Which is the single tube of which the greatest number were made, and, 2) 
what was its main application?

Ken W7EKB