Vacuum tube technology.
GE picture tube- and CRT-related information is in the General Electric Section.
Dumont - Data and application notes from Allen B. Dumont Labs.
Eimac - Data and application notes from Eimac.
Electrons Inc. - Data from Electrons Inc.
FTR - Data from FTR (Federal Telephone & Radio).
GE - Tube-related data from General Electric
Hughes - Tube-related data from Hughes, Inc.
Hytron - Data from Hytron.
Ken-Rad - Data from the Ken-Rad Co., before the 1945 aquisition
by General Electric. 
Machlett - Tube data from Machlett Laboratories Inc.
National Union - Data and application information
from National Union.
Raytheon - Tube data from Raytheon Production Co.
RCA - Tube-related data from RCA
Signalite - Data and application information
from Signalite, a neon glow tube manufacturer. 
Sylvania - Tube data from Hygrade Sylvania, later known as
just Sylvania.
Tung-Sol/Chatham - Data and application information
from Tung-Sol, as well as its Chatham division.
United - Tube data from United Electronics, a Newark tube company that
specialized in industrial power tubes, mostly low-tech.
Vacuum Tube Products/H.W. Ulmer/MU - Documents and specs
from the three companies formed by Harold. W. Ulmer: Vacuum Tube Products, H.W. Ulmer Co., and MU Inc.
Westinghouse - Data and application notes from Westinghouse's
tube department.
Military - US military documents on tube technology.
Catalogs and data relating to manufacturing tubes
