Fleming_valves.jpg
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Summary
Description Fleming valves.jpg |
English:
The first prototype
Fleming valves
. The Fleming valve, invented in 1904 by
John Ambrose Fleming
, as a
detector
for radio waves in early
radio receivers
, was the first
thermionic diode
and the first
vacuum tube
. The basic configuration consisted of an evacuated glass bulb containing two
electrodes
: a
cathode
in the form of a wire
filament
heated white-hot by a current through it, and a metal
anode
usually consisting of a flat
plate
. Since only the filament produces electrons, the current of electrons through the tube can only pass in one direction, from filament to anode. In these early tubes, the filament is the vertical loop of wire, while the anode has various shapes, such as the coil of wire in the lefthand tube. The caption says: "
Photograph of the oscillation valves first employed by Dr. J. A. Fleming, FRS, in October 1904, for the rectification of high-frequency electric oscillations as used in wireless telegraphy
"
|
Date |
between 1904 and 1919
date QS:P,+1950-00-00T00:00:00Z/7,P1319,+1904-00-00T00:00:00Z/9,P1326,+1919-00-00T00:00:00Z/9
|
Source | Downloaded July 18, 2013 from John Ambrose Fleming (1919) The Thermionic Valve and its Developments in Radiotelegraphy and Telephony , The Wireless Press, London, frontispiece on Google Books |
Author | John Ambrose Fleming |
Licensing
Public domain Public domain false false |
This media file is in the
public domain
in the
United States
. This applies to U.S. works where the copyright has expired, often because its first
publication
occurred prior to January 1, 1929, and if not then due to lack of notice or renewal. See
this page
for further explanation.
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This image might not be in the public domain outside of the United States; this especially applies in the countries and areas that do not apply the
rule of the shorter term
for US works, such as Canada, Mainland China (not Hong Kong or Macao), Germany, Mexico, and Switzerland. The creator and year of publication are essential information and must be provided. See
Wikipedia:Public domain
and
Wikipedia:Copyrights
for more details.
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