7.
The space charge within a diode tube is best described as a
charge that
a.
is constantly varying in density.
b.
maintains a positive potential with respect to the cathode.
c.
builds up to a point of equilibrium at which it has neither
negative nor positive characteristics.
d.
remains at a negative potential, regardless of whether a
positive or a negative charge is applied to the plate.
8.
Figure 25 of TM 11-662 shows a characteristic curve for a diode.
This curve shows the relationship between the
a.
plate voltage and plate current.
b.
plate current and filament voltage.
c.
filament current and plate voltage.
d.
space charge voltage and plate current.
SITUATION
Assume that you are analyzing the characteristic curves of a
diode tube to determine if the tube is acceptable as the rectifier in
a power supply. The characteristic curves for the tube are shown in
figures 29 and 30 in TM 11-662.
Exercises 9 through 13 are based on the above situation.
9.
Curve ABC in figure 29 is relatively flat along the portion from
B to C. This flattened portion of the filament voltage-plate current
curve is caused by the
a.
space charge in the tube.
b.
secondary emission in the tube.
c.
temperature saturation of the tube.
d.
dynamic characteristics of the tube.
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