What is the purpose of the electromagnetic field which surrounds a traveling-wave tube?
A. To accelerate the electron
B. To velocity modulate the electron beam
C. To keep the electrons from spreading out
D. To slow down the signal on the helix
Answer: Option C
Coupling into and out of a traveling-wave tube can be accompanied by a
A. Waveguide match
B. Cavity match
C. Direct coax-helix match
D. All of the above
A. A long time constant
B. Low-pass filters
C. The shortest possible time
D. The restricted high-frequency response
A. $${\text{S}} = \frac{{2\lambda {\text{R}}}}{{\text{L}}}$$
B. $${\text{S}} = \frac{{3\lambda {\text{R}}}}{{\text{L}}}$$
C. $${\text{S}} = \frac{{\lambda {\text{R}}}}{{\text{L}}}$$
D. $${\text{S}} = \frac{{\text{L}}}{{\lambda {\text{R}}}}$$
The aquadag coating on the inside of PPI tube is used
A. To focus the beam of primary electrons
B. To shield the electron beam from unidirectional magnetic
C. As a second anode and to prevent the build-up of secondary field
D. All of these
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