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Definition of semiconductor:
A material that can sometimes conduct an electric current and sometimes not, depending on the voltage applied across that material.
What is voltage ripple?
The fluctuation in the voltage applied to the x-ray tube expressed as a percentage of peak kilovoltage.
What is the purpose of the autotransformer?
To vary and control the amplitude of the voltage supplied to the high-voltage step-up transformer and the filament transformer.
Which component supplies precise voltage to the filament cirucuit & to the high-voltage circuit of the x-ray imaging system?
the autotransformer
The number of electrons emitted by filament is determined by the _______ ________.
filament temperature
(as current increases, temp increases... therefore more electrons released via thermionic emission) too much heat, can damage the filament
Define AEC
An electronic device designed to terminate x-ray exposure after properly exposing an image receptor.
What is rectification?
The process of changing alternating current and voltage into direct current and voltage.
How does primary voltage relate to secondary voltage in an autotransformer?
Primary and secondary voltage are in direct relation to the number of turns of the transformer.
The primary voltage input of the autotransformer is 220V, but the output is controllable from appx ____ to _____V.
100-400
The product of tube current and exposure time is ____, which is also electrostatic charge (C).
mAs
What does the line compensator do?
Adjusts the voltage to the x-ray imaging system to a constant value, to compensate for fluctuations in voltage supplied by the power company.
What is an autotransformer?
A type of transformer having a single winding.
What are the three main components of the x-ray tube?
1) console
2) x-ray tube
3) high-voltage generator
Which meter is placed across the output terminals of the autotransformer to read the voltage?
kVp meter
(the low voltage becomes the input to high-voltage step-up transformer that increases voltage to selected kVp)
1) Radiation "QUALITY" is defined as:
2) It is expressed in....
1) penetrability or energy
2) kVp or HVL
What is a capacitor?
An electric circuit device that stores electric charge
What is the product of voltage and current?
Power (watt)
What are the two components that make up the high-voltage generator?
1) high-voltage step-up transformer
2) rectification circuit
The electric tube current that crosses from the cathode to the anode is measured in ______.
milliamperes (mA)
Precision resistors result in ________.
(100, 200, 300 & higher)
Where is the mA meter located?
Connects at the center of the secondary winding of the high-voltage step-up transformer in series with the x-ray tube. This reduces the possibility of shock.
List the 5 major controls on the operator's console?
1) On/off control
2) kVp selection
3) mA selection
4) time (mAs) selection
5) AEC
1) Radiation "QUANTITY" is defined as:
2) How is it expressed?
1) intensity or # number of x-rays
2) mGya or mGya/mAs
The filament current normally operates at ___ to ___ A.
3-5 amperes
Which transformer in the x-ray circuit is a step-down transformer?
the filament transformer