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| The famous beam power valve type KT-66
made in England by MO-Valve |
In Electronics old times, inventors,
engineers, scientists and same manufacturers if had not only
involved in constants and long relative legal processes the
breaking of rights of manufacture as of patents covering devices,
components, as well as electronic circuits. Thus, in the Termionic
field the rule could not be differentdid and, circa of 1939,
in intention to prevent the breaking of patents that protected
the pentode valve, made that some manufacturers after intense
research of laboratory launched in the market the first electron
beam power valve, known as directed beam tetrode. In the reality,
this type of valve can in such a way have the structural configuration
of one tetrodo as of one pentode and received this denomination
for being constructed of form that the electrons circulate in
intent beams of the catode through the screen until the plate.
Thus, the main differences this valve, when compared with the
tetrodes and conventional pentodes, they inhabit in the fact
that in the spaces in the screen is lined up, possesss two plates
producers of beams and, generally the space enters the shield
screen and the plate is biggest. As the spaces between screen
meet lined up, few electrons that collide against the shield
grating and, therefore, the anodic current is greater that when
compared with pentodes. In this type of valve the secondary
emission is reduced due to space load enters the shield screen
and the plate. The space load is a resultant phenomenon of the
lockwire of electrons when they pass of the gratings of raised
shield of potential for the plates where the same it is lesser.
Thus, the formed space load in the front of the plate is enough
to banish secondary electrons from the same one, emitted as
resulted of the collision of primary electrons.
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| Several types of beam power valve type
6L6 made in the USA. From left to right bulbs types CC,
G and metal |
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Internal structure of a beam power valve
Beam-confining electrode
Cathode
Grid
Screen
Plate |
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