|
Dr. DeForest em 1905 |
|
|
O Audion de Lee De Forest de 1907, apenas
com uma placa (single win) e com filamento de tântalo. |
|
In
1907, U.S. patent nš 841.387, entitled "Device for amplifying
Feeble Electric Currents", was issued to the inventor Lee De
Forest by adding a third element to the Fleming valve, or the
grid. This all importante paper in the amplifier's evolution
describes its fundamental property: the output current is controlled
by an electrode that does not draw appreciable current itself.
Since scientific and technologial discoveries are great events,
but generally they pass a period of inaction, in spite of the
enormous potential of the grid audion, its application was not
immediate.
Inittialy it was used as wireless detector rather than an amplifyer.
This latter capability was first employed only a few years later,
based on the pioneer research work of several scientists and
engineers. |
The De Forest
experiment:
|
1º - The original idea of audion
in the conductivity of gases. Two electrodes in a flame
was the first audion detector.The origin of the word thermionics. |
|
|
2º - The first audion valve consisted
of two hot electrodes in a gaseous medium. |
|
|
3º - The first audion valve Audion.
- Radio
News |
|
|
|