Question | Answer |
A material that can conduct an electric current or not, depending on the voltage applied across that material. | semiconductor |
An electronic device designed to terminate x-ray exposure after properly exposing an image receptor. | AEC |
A method of adjusting the voltage to the x-ray imaging system to a constant value, in response to changes in voltage supplied by the power company. | line compensation |
An electrical circuit device that stores electric charge. | capacitor |
Place in the tube circuit, connected 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. | mA meter location |
An electrical device that contains two electrodes. | diode |
The fluctuation in the voltage applied to the x-ray tube expressed as a percentage of peak kilovoltage. | voltage ripple |
The process of changing alternating current and voltage into direct current and voltage. | rectification |
A type of transformer having a single winding. | autotransformer |
The product of voltage and current; Watt. | power |
220 V is supplied across 1200 windings of the primary coil of the autotransformer. If 1650 windings are tapped, what voltage will be supplied to the primary coil of the high-voltage transformer? | 302.5 V |
A kVp meter reads 86 kVp and the turns ratio of the high-voltage step-up transformer is 1200. What is the true voltage across the meter? | 71.7 volt peak |
The supply voltage from the autotransformer to the filament transformer is 60 V. If the turns ratio of the filament transformer is 1/12, what is the filament voltage? | 5 V |
If the current in the primary of the filament transformer was 0.5 A with a turns ratio of 1/12, what would be the filament current? | 6 amps |
The supply to a high-voltage step-up transformer with a turns ratio of 550 is 190 V. What is the voltage across the x-ray tube? | 104.5 kV |
Allows relatively undiminished intensity of x-rays through the tabletop. | 90/20 table |
List the 5 major controls on the operator's console. | On/off control, kVp selection, mAs selection, time (mAs) selection, and automatic-exposure controls. |
Purpose of the autotransformers. | to vary and control the amplitude of the voltage supplied to the high-voltage step-up transformer and the filament transformer. |
Primary/secondary voltage relationship in autotransformers. | Direct relation to the number of turns of the transformer. |
What the prereading kVp meter allows. | The precise adjustment of the supply voltage and monitoring the kVp before the x-ray exposure. |
200 mA and 1/60 of a second equals what mAs? | 3.3 |
600 mA and 30 milliseconds equals what mAs? | 18 |
What is the difference between high voltage transformer and high voltage generator? | The high-voltage transformer is just one component of a high-voltage generator. |
In order that a reverse voltage is not applied across the x-ray tube and that the tube operates most efficiently, x-ray tubes use ____ current. | direct |
Direct current is archived in the x-ray circuit through? | rectification |
Voltage ripple of single-phase generator. | 100% |
Voltage ripple of three-phase, six-pulse generator. | 14% |
Voltage ripple of three-phase, twelve-pulse generator. | 4% |
Voltage ripple of high-frequency generator. | 1% |
0.7(mA)(kVp)/1000 is the equation for computing _____ power rating. | single-phase |
(mA)(kVp)/1000 is the equation for computing ____ or ____ power ratings. | three-phase, high-frequency |
Graph showing the cooling rate of an x-ray tube housing. | housing cooling chart |
Radiation emitted through the x-ray tube housing (other than the primary beam). | leakage radiation |
Measure of heat capacity (1HU=1AVs=1Ws=1J). | heat unit |
Shroud inside the x-ray tube surrounding the cathode to concentrate electrons on the focal spot. | focusing cup |
Anode rotation speed. | 3400 rpm or 10,000 rpm |
Tungsten alloyed with thorium. | Thoriated tungsten |
Cathode to anode electron flow. | x-ray tube current |
X-ray tube capable of high speed switching. Voltage applied to the focusing cup is the switch. | grid-controlled x-ray tube |
Method of heat transfer by a moving fluid medium(liquid or gas). | convection |
Electron cloud in the vicinity of the filament. | space charge. |
Three methods used to support the x-ray tube. | Floor, wall, or ceiling mounted. |
Where thoriated tungsten would be used in a x-ray imaging system. | cathode and anode |
When all available electrons are projected from the cathode to the anode. | saturation current |
Why are arcing and tube failure no longer a problem in modern x-ray tube design? | heavy filaments and high capacity anodes |
Pass an electric current to heat a conductor and cause outer-shell electrons to be released from the conductor. | thermionic emission |
Principal cause of tube failure. | broken filament |
What addition to the filament material prolongs tube life? | thorium |
Why is the filament embedded in the focusing cup? | To electrostatically shape the beam |
Why would an x-ray tube need a large focal spot? | high intensity radiation |
Why would an x-ray tube need a small focal spot? | better spatial resolution |
Negative side of the x-ray tube. | cathode |
positive side of the x-ray tube | anode |
Name 2 types of anodes. | Fixed and rotating |
Three functions of the anode. | X-ray tube target, electrical and thermal conductor, and mechanical support. |
How does atomic number affect the selection of anode target materials? | high atomic number=efficient x-ray production. |
How does thermal conductivity affect the selection of anode target material? | thermal conductivity=heat dissipation |
How does melting point affect the selection of anode target material? | melting point=heat capacity |
How does the anode rotate inside a glass enclosure with no mechanical connection to the outside? | induction motor |
Higher x-ray intensity on the cathode side. | Anode heel effect |
How can anode heel effect be used advantageously? | positioning thicker anatomy on cathode side |
Name three causes of tube failure. | cracked or pitted anode, induction motor failure, and open filament. |
How can space charge be removed? | increase kVp |
X-ray tube locking-in at center and at a given SID. | detent position |
a material that transmits x-rays and appears dark on a radiograph. | radiolucent |