On Sun, 6 Aug 2006 21:11:01 -0400, "Al"
wrote:


wrote in message
...
Why do some people call Tubes,Valves?
cuhulin


Originally named Fleming's valve, after the inventor of the vacuum tube.
Al

Like most cool ****, there was no single inventor.

''Though the thermionic emission effect was observed as early as 1873,
it is Thomas Edison's 1883 investigation of the "Edison Effect" that
is the best known. He promptly patented it (U.S. Patent 307031), but
as the particle nature of the electron was not known until 1897, he
did not understand the process.

[edit]
Diodes and triodes
John Ambrose Fleming had worked for Edison; in 1904, as scientific
adviser to the Marconi company, he developed the "oscillation valve"
or kenotron. Later known as the diode, it allowed electric current to
flow in only one direction, enabling the rectification of alternating
current. Its operation is described in greater detail in the previous
section.

In 1906 Lee De Forest placed a bent wire serving as a screen between
the filament and plate electrode, later known as the "grid" electrode.
As the voltage applied to the grid was varied from negative to
positive, the amount of electrons flowing from the filament to the
plate would vary accordingly. Thus the grid was said to
electrostatically "control" the plate current. The resulting
three-electrode device was therefore an excellent and very sensitive
amplifier of voltages. DeForest called his invention the "Audion". In
1907, DeForest filed U.S. Patent 879532 for a three-electrode version
of the Audion for use in radio communications. The device is now known
as the triode. De Forest's device was not strictly a vacuum tube, but
clearly depended for its action on ionisation of the relatively high
levels of gas remaining after evacuation. The De Forest company in its
Audion leaflets warned against operation which might cause the vacuum
to become too hard. The first true vacuum triodes were the Pliotrons
developed by Irving Langmuir at the General Electric research
laboratory (Schenectady, New York) in 1915. These were closely
followed by the French 'R' Type which was in widespread use by the
allied military by 1916. These two types were the first true vacuum
tubes.''

-wikipedia