9.
Assume that the load resistance of the high-level modulator shown in
Figure 70 is equal to 1,000 ohms and that a positive trigger voltage
causes tube V2 to conduct. The PFN will discharge and the amplitude
of the pulse developed across the primary of transformer T1 will be a
negative
a.
15 KV with a duration time of 1.5 microseconds.
b.
15 KV with a duration time of 0.75 microseconds.
c.
7.5 KV with a duration time of 1.5 microseconds.
d.
7.5 KV with a duration time of 0.75 microseconds.
10.
The charging resistance Rch is used to control the charge time of the
pulse-forming network and to
a.
prevent the PFN from discharging before V2 conducts.
b.
control the duration of the voltage developed across T1.
c.
allow the PFN to charge to a voltage that is approximately twice
the power supply voltage.
d.
prevent tube V2 from short-circuiting
the
high-voltage
power
supply during the discharge of the PFN.
11.
The current flow through the switching tube V2 will cease when
a.
switch S3 is opened.
b.
a negative trigger is applied to the grid of V2.
c.
the voltage across the pulse-forming network is zero.
d.
the pulse-forming network is completely charged to 15 KV.
97
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