12
2-29. In a twt, what is the purpose of the
attenuators along the helix?
1. To focus the beam
2. To limit the input
3. To limit the output
4. To prevent reflections
2-30. A microwave tube that extracts energy
from a wave that travels from the
collector toward the cathode is referred
to as the
1. klystron
2. traveling-wave tube
3. crossed-field amplifier
4. backward-wave oscillator
2-31. In a magnetron, the magnetic field
between the plate and cathode serves
what purpose?
1. Acts as a grid
2. Provides a plate load
3. Acts as a space-charge suppressor
4. Provides filament power
2-32. What property in a magnetron is
controlled by the cavities in the plate?
1. Input power
2. Output power
3. Input voltage
4. Output frequency
2-33. In a magnetron, what causes the path of
an electron to curve when it is moving
from the cathode to the plate?
1. The cathode pulse
2. The electric field
3. The resonant cavities
4. The permanent magnetic field
2-34. The critical value of magnetic field
strength in a magnetron causes which of
the following electronic actions?
1. Plate cavities stop oscillating
2. Output power decreases to zero
3. Electrons strike the plate and return to
the cathode
4. Electrons miss the plate and return to
the cathode
2-35. Magnetron oscillators are divided into
what total number of classes?
1. One
2. Two
3. Three
4. Four
2-36. THIS QUESTION HAS BEEN
DELETED.
2-37. In a negative-resistance magnetron,
which, if any, of the following values of
magnetic field strengths is required to
start oscillations?
1. Critical value
2. Slightly lower than critical value
3. Slightly higher than critical value
4. None of the above
2-38. In magnetrons, the effect of filament
bombardment can be reduced by which
of the following actions?
1. Increasing plate voltage
2. Reducing filament voltage
3. Reducing signal frequency
4. Increasing signal frequency
2-39. In electron-resonance magnetrons, which
of the following anode blocks is/are
used?
1. Vane anode
2. Rising-sun anode
3. Hole-and-slot anode
4. Each of the above
