Deck 'D' Flashcards
1
Q
What are the three primary controls of X-rays?
A
- kVp - quality, penetrating power of photons
- mA - quantity
- Time - quantity
2
Q
What are the three main components of an X-ray machine?
A
- Circuit to heat filament
- Circuit to apply a large p.d. between the cathode and anode to accelerate electrons
- Timing device for exposure length
3
Q
Describe the filament circuit of an X-ray tube.
A
- Heats tungsten to at least 2200 degrees Celsius to emit a useful number of electrons
- Step down transformer 220V -> 10V
4
Q
Describe the high voltage circuit of an X-ray tube.
A
- Produces a large p.d.
* Converts high Amperage to mA and high kV
5
Q
What is rectification?
A
The process of converting AC to DC to ensure electrons only flow from the cathode to the anode.
6
Q
What is a half-wave rectifier versus a full-wave rectifier?
A
Half-wave:
- One diode
- Forward bias
- Negative cycle won’t conduct
- Constant polarity
- Half the frequency
- ^-^-^-^-^-
Full-wave: * Four diodes * No bias - uses negative wave * Double the frequency ^^^^^^^^
7
Q
What is single-phase power?
A
A single wave form which allows the main current’s potential to drop to zero with each change of current flow.
8
Q
What is three-phase power?
A
Three waves of power flowing at evenly spaced intervals from each other, starting before the other depletes so it never reaches zero.
