8-37D: Display System Power Supplies

Question 1

8-37D2

The display power supply provides the following:

A. 5 volts DC for logic circuits.
B. +/-12 volts DC for analog and sweep circuits.
C. 17kV DC for the CRT HV anode.
D. All of the above

Answer 1

ANSWER D
The power supply in a cathode ray tube display will include 17 kV DC for the display tube high voltage annode, 12 volts for analog and sweep circuits, and 5 volts DC for logic circuits.

Question 2

8-37D3

ln a display system power supply, what is the purpose of the chopper?
A. lt acts as an electronic switch between the raw DC output and the inverter.
B. lt interrupts the AC supply line at a varying rate depending on the load demands.
C. lt regulates the 5 volt DC output.
D. lt pre-regulates the AC input.

Answer 2

ANSWER A
ln a RADAR power supply, the purpose of the “chopper” is to switch the input DC current to a pulsating direct current that may then be fed to the inverter’s power transformer. High speed switching transistors called “switchers” may handle large amounts of current.

Question 3

8-37D5

What would be a common switching frequency for a display system
power supply?

A. 18 kHz
B. 120 Hz
C. 60 kHz
D. 120 kHz

Answer 3

ANSWER A
Most switcher display power systems operate at 18 kHz.