Very much On Topic: Integrated Vacuum Tubes

[James Fogg]

> > I think acorn tubes are smaller.  Those are UHF tubes -- I 
> think they 
> > were used in 1940s or 1950s vintage equipment for oscillators or
> 
>    Ummmm - no.  A nuvistor could very nearly fit into the 
> acorn's envelope. 
> Nuvistors look like a largish metal pencil eraser - they're 
> substatially smaller internally than an acorn tube, as well.  
> And of course, as you mention, 30 years later in design.

Not smaller, but more along the lines of classic (glass, pin sockets)
tubes. Motorola WWII walkie-talkies used "pencil tubes". I've only seen
them once, about the size of a small woman's pinkie finger.