Expo convertors with tubes ?

[CHoaglin at aol.com]

In a message dated 12/7/99 5:15:04 PM, uzs159 at uni-bonn.de writes:

<< Hehe, CdS is a semiconductor. One could argue that there are no junctions,

and that these devices were known in the 50's. (I'm not sure about the last

one.)  >>

They go back a ways...I've got a couple large ones in metal can packages with 
quartz windows that have 1964 date codes..I think I'm going to use them to 
build a light controlled "theremin"

Chris