15 Mar

File:Audion tube.jpg

‎{{int:filedesc}}: Added to description that the tube was inadequately evacuated
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Revision as of 21:00, 15 March 2013
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=={{int:filedesc}}==

=={{int:filedesc}}==

{{Information

{{Information
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|description={{en|1=A De Forest [[:en:Audion|Audion]] tube, the first [[:en:vacuum tube|electron tube]] that could [[:en:amplification|amplify]]. The first [[:en:triode|triode]], or tube with three electrodes, a [[:en:electrical filament|filament]], [[:en:grid (electricity)|grid]], and [[:en:plate electrode|plate]], the audion was invented in 1906 by American inventor [[:en:Lee De Forest|Lee De Forest]]. This example is burned out; only the ends of the filament wires are left, visible in the center of the tube. This tube has two connected grids ''(zigzag wires)'' on either side of the filament, and two plates ''(outside the grids)''. The filament was connected to the screw terminal at bottom, while the grid and plate connections were brought out to wires at the top.

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|description={{en|1=A De Forest [[:en:Audion|audion]] tube, the first [[:en:vacuum tube|electron tube]] that could [[:en:amplification|amplify]]. The first [[:en:triode|triode]], or tube with three electrodes, a [[:en:electrical filament|filament]], [[:en:grid (electricity)|grid]], and [[:en:plate electrode|plate]], the audion was invented in 1906 by American engineer [[:en:Lee De Forest|Lee De Forest]]. The filament was originally in the center of the tube, but in this tube is burned out; only the ends of the filament wires are left. The two connected grids ''(zigzag wires)'' are visible on either side of the filament, and the two plates are outside the grids. The filament was connected to the screw terminal at bottom, while the grid and plate connections were brought out to wires at the top. Manufactured for a few years beginning about 1913, the residual air left in the first audion tubes due to inadequate evacuation created ions that caused the tube to function erratically, and reduced the life of the filament. This is evidenced by the deposit of material on the inside of the glass envelope, sputtered off the filament by ion bombardment.

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The caption of the picture read: "''This is a real old De Forest audion. Several years ago radio amateurs saved for long periods to procure one of these magic bulbs. As may be observed, two filaments, two grids, and two plates were employed. The stability of this type tube was anything but constant due to imperfect evacuation.''"

The caption of the picture read: "''This is a real old De Forest audion. Several years ago radio amateurs saved for long periods to procure one of these magic bulbs. As may be observed, two filaments, two grids, and two plates were employed. The stability of this type tube was anything but constant due to imperfect evacuation.''"

http://commons.wikimedia.org/w/index.php?title=File:Audion_tube.jpg&diff=92642970&oldid=92612147