UV199_prototype

Early in 1921 developmental work was done in the GE Research laboratories at Harrison, New Jersey on a tube which would be small in size and having a low filament current. The tube was double ended, with no bases. Connecting wires were of stubby copper extending about 5 mm from the glass. The filament connections were at each end and anode and grid from the opposite ends, each about 5 mm from the filament wire.. The tube was manufactured in a very limited quantity but was designed for use in a portable radio designed by GE. In December 1921 the filament wire was reduced in width to .6 mm (from .9 mm), which produced a current of .06 amps.In May 1922 the tube was redesigned to have the 4 pin UV199 base.