Rectification Flashcards
what is rectification?
a diode redirects filament current before supplying the cathode
where are rectifiers located?
in the circuit between the secondary side of the transformer and the x-ray tube
two methods of rectification
suppressing the negative side of the sine wave of current, and changing the negative to a positive cycle
is a negative or positive sine wave useful for the x-ray tube?
positive sine wave
which type of rectification occurs naturally or normally within the x-ray tube and should be prevented?
self-rectification
when does self rectification occur?
when there is an excess of electrons at the target anode and a deficiency of electrons at the filament with no tube potential, so electrons will move back toward filament
limitations of self rectifications
low kV, low mA (insufficient penetration of large parts and insufficient densities)
what type of rectification is used today?
diode rectification
The PRIMARY disadvantage of self rectification is:
the limitation of high exposure factors
In a three phase half wave rectified unit, there are how many rectifiers?
6
During the positive half of the cycle, the rectifiers are:
conductive
During the negative cycle the reverse voltage is actually higher than the useful voltage. This is caused by:
change in transformer polarity
With three-phase full wave rectified equipment, the voltage across the x-ray tube:
drops about 3%
In the event that while conducting a spin top test, you see 8 dots on the QC image when 10 was expected which of the following may be the reason?
time inaccuracy
In a P-N type rectifier, the side with gallium has a(n) __________________ .
deficiency of electrons
