LESSON 5 - MULTIELEMENT TUBES
LESSON EXERCISES
In each of the following exercises, select the ONE answer that
BEST completes the statement or answers the question. Indicate your
solution by circling the letter opposite the correct answer in the
subcourse booklet.
1.
The tetrode and pentode tube types often are used in place of
the triode at frequencies between the audio and microwave ranges. In
general,
the
triode
requires
neutralizing
circuits
at
high
frequencies because the
a.
interelectrode capacitance couples an undesirable feedback
from the output circuit back to the input circuit.
b.
secondary emission creates a negative resistance region in
the tube's transfer characteristic.
c.
single control grid cannot withstand the high frequency plate
current.
d.
amplification factor is often too large for high-frequency
applications.
2.
A fourth electrode, called the screen grid, exists in a tetrode,
which is not found in a triode. The purpose of the screen grid is to
a.
act as an electrostatic shield between the control grid and
the plate, thus reducing Cgp .
b.
shield the
control
grid
from
the
effects
of
secondary
emission.
c.
supplement the controlling action of the control grid.
d.
collect electrons that do not reach the plate.
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