13
Figure 2A.
Cold-cathode tube operation.
2-30.
If the source voltage in figure 2A is
increased to 150 volts and the ammeter
reads 20 milliamperes, what is the
resistance (rkp) of the tube?
1. 2.65 k
W
2. 5.25 k
W
3. 6.25 k
W
4. 8.15 k
W
2-31.
The electron gun of the CRT serves
which of the following functions?
1. Deflects electrons into the plate
2. Concentrates electrons into a beam
3. Emits electrons
4. Both 2 and 3 above
2-32.
Which of the following is a description
of the grid in a CRT?
1. A metal cap with a hole in the
center
2. A metal cap at ground potential
3. A metal cap with a positive
potential
4. A metal cap with a wire screen in
the center
2-33.
What element of a television CRT is
adjusted by the brightness control?
1. Cathode
2. Aquadag
3. Control grid
4. Focusing anode
2-34.
Which of the following elements of the
CRT helps prevent the beam of
electrons from diverging?
1. Cathode
2. Aquadag
3. Focusing anode
4. Decelerating anode
2-35.
Which of the following elements of a
CRT has the highest positive potential?
1. The focusing anode
2. The electronic lens
3. The accelerating anode
4. The decelerating anode
2-36.
What is the name of the florescent
material that coats the inside face of a
CRT?
1. Posporus
2. Phosphor
3. Flourine
4. Flourese
2-37.
What is the purpose of the aquadag
coating in the CRT?
1. It is used as a plate
2. It is used to focus the beam
3. It eliminates the space charge
4. It eliminates the effects of
secondary emission
