The remarkable achievements in the field of electrons, which
includes radio, radar, television, guided missiles, etc., are a
direct result of the discovery of the vacuum tube.
greatest advance in the development of vacuum tube theory and
application was the audion tube of Lee DeForest.
feature of this tube was the insertion of a third electrode in the
diode that Fleming had developed. DeForest used his third electrode
which was placed between the plate and the amount of electron flow.
Because of the form of this control electrode in the earlier tubes,
the term grid was applied to it.
The grid is now defined as an
electrode that contains openings through which electrons may pass.
Physically, it is constructed of mesh, screen or spiral wires placed
between the plate and cathode.
Many modern tubes contain more than one grid; so to describe its
function as well as to differentiate it from other grids, this third
electrode is called a "control grid."
A tube which contains three
active elements--a cathode, a control grid, and a plate--is called a
"triode." In this lesson you will study the construction, operation
and characteristics of the triode.
TM 11-662, chapter 4, paragraphs 32-44.
Signal Subcourse SS0311
When you complete this lesson you will be able to:
Characterize and explain the function of the control grid.