GE - General Electric
In 1892 Thomas Edison and three other men founded the General Electric Company. Edison is credited to be the inventor of the lightbulb. He has many other inventions and patents on his name and with Nicolas Tesla he’s seen as one of the great inventors of the 20th century.
Thomas Edison with his invention the lightbulb
Edison and Tesla had their differences but their main issue was about the implementation of Alternating Current (AC) which Tesla advocated or Direct Current (DC) preferred by Edison, to power the grid to supply electricity for households. As we all know now AC won the war because the losses for transport are much lower than with DC.
The first hydro-electric power plant generating AC was built at the Niagara Falls with Westinghouse/Tesla generators.
Tesla AC power generators at the Niagara Falls
Direct Current has been very useful in all kind of electric circuits and almost every electric appliance has a power supply that converts AC into DC.
The invention of the lightbulb was a first step towards the development of the vacuum tube. The filament in a lightbulb has the sole purpose to radiate light, but in a vacuum tube the light is a byproduct because the generated heat is used to emit electrons from a cathode to a positively charged anode controlled by a grid between the cathode and anode.
One of the most important steps to a proper functioning of the vacuum tube was the diffusion pump by one of the engineers of GE Irving Langmuir, to get a good vacuum inside the tube. He also solved a couple of problems to stretch the life of the tungsten wire (filament) inside the tube.
In 1919 RCA short for the Radio Corporation America was founded by three companies Westinghouse, AT&T and GE to serve as their sales channel for tubes and radio receivers. In 1930 both GE and Westinghouse had to give up their share in RCA due the anti-trust enforcement.
In the 1950’s GE started a series of high quality and more reliable tubes they branded the ‘Five Star’ range for critical applications. These tubes are now much in command and one popular version of GE is the GL-5751 a lower gain version (70%) of the 12AX7 tube. Other tube manufacturer like Sylvania and RCA respectively had their ‘Golden Brand’ and ‘Command Series’.
GE Five Star 5751
In 1918 Ray Burlow took over the Kentucky Electrical lamp Company and renamed it to the Kentucky Radio Corporation or Ken-Rad. In 1922 Ken-rad started with the production of vacuum tubes for radio’s. Their first commercial tube was the KR1 rectifier.
KenRad 6Z4 rectifier
On the evening of May the 24th 1935 the first major league baseball game played at night was lighted by Ken-Rad lamps which were switched on by the American president Franklin Delano Roosevelt.
In 1945 Ken-Rad was sold to GE and till 1952 Ken-Rad tubes were still manufactured in Kentucky under the name Ken-Rad.
Blackplated Ken-Rad 12AX7