12.
If the milliammeter shown in the cathode circuit of V3 (Figure 70)
indicates an abnormally high current reading, the probable cause of
this reading is
a.
a change in the magnetron's impedance.
b.
a change in the value of Rch.
c.
an open charging resistance.
d.
a decrease in the pulse repetition frequency (PRF).
13.
The network composed of C2 and R4 is used to filter the pulsating
current through V3 and to produce an average current reading on the
milliammeter. Electron tube V3 will conduct when
a.
V1 stops conducting.
b.
the PFN becomes fully charged.
c.
V2 is triggered by the positive timing pulse.
d.
the magnetron causes a negative pulse to be reflected back into
the primary of T1.
14.
When tube V2 conducts in the modulator circuit shown in Figure 70,
then pulse-forming network will discharge through
a.
the primary of T1, R2, and V2.
b.
the primary of T1, R4, R3, and V3.
c.
the primary of T1, high-voltage power supply, Rch, and V1.
d.
V1, Lch, high-voltage power supply, R4, C2, milliammeter, R3, and
V3.
SITUATION
Assume that switch S1 is moved to position B in the circuit shown in Figure
70, and that the pulse repetition frequency of the radar set is 400 pulses
per second.
Exercises 15 through 20 are based on the above situation.
98
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