Unit 2

A single-phase waveform has ___ ripple.

100% voltage ripple

The incoming power to a step up transformer is 100 V, 10 A with a turns ratio of 250:1 (secondary:primary). What is the resulting voltage in this transformer? 25,000 kV 25,000 V 0.4 kV 0.4 V

100/x=1/250 100/x= .004 100=.004x x=25000 25,000v

A single phase full wave rectified system produces _____ pulses per cycle. 1 2 6 12

2

The filament in the x-ray tube requires ______amperes to emit electrons, thermionic emmission. 0.5-1 1-2 3-5 not enough information to answer

3-5 amperes

Low capacity x-ray tube rotors revolve at a minimum ___ rpm. 2000 3600 6000 10,000

3600

Nearly all hard wired equipment operates on incoming line voltage of: 440 V 120 AC 120 Hz 210 A

440V

When electrons bombard the target, ___% of their kinetic energy is converted to heat.

99%

A diode allows electrons to flow from ____. anode to cathode cathode to anode cathode to cathode anode to anode

A diode allows electrons to flow from cathode to anode *Direct current

As an x-ray tube ages, the inside can become coated with tungsten, which can cause ___ in the tube. convection anode pitting on-focus radiation arcing

As an x-ray tube ages, the inside can become coated with tungsten, which can cause arcing in the tube.

Which of the following transformers has one winding? Filament transformer Hi voltage transformer Autotransformer none of the above

Autotransformer

In single phase power systems, the potential never drops to zero.

False

AC current is required in the x-ray tube, and DC current is required in the transformers

False AC is required in the transformers for energy efficiency, and DC is required in the X-ray tube so that it is always from the cathode to the anode.

The basic x-ray circuit is divided into the main circuit and the anode circuit.

False The basic x-ray circuit is divided into primary/operating console circuit, secondary/high voltage circuit, and filament/X-ray tube circuit

The high voltage generator consists of a high voltage transformer, rectifiers and an autotransformer

False The high voltage generator consists of a high voltage transformer, rectifiers, and diodes.

The mAs in a system controls the quality of the beam.

False kVp controls the quality of the beam

All of the following are principle parts of the x-ray system except? the tube high voltage generator Filament transformer operating console

Filament transformer

Full-wave rectified, three-phase units provide an x-ray beam at ___ pulse(es) per second. 1 60 120 360

Full-wave rectified, three-phase units provide an x-ray beam at 360 pulse(es) per second.

Variations in power distribution to the x-ray machine are corrected by the ____.

Line voltage compensator

The automatic exposure control (AEC) terminates the exposure when ____.

The automatic exposure control (AEC) terminates the exposure when sufficient amount of radiation reaches the IR.

The high voltage generator contains the high voltage transformer, the ___, and the ___. a. autotransformer, timer b. timer, rectifiers c. kVp meter, filament transformer d. filament transformer, rectifiers

The high voltage generator contains the high voltage transformer, the filament transformer, and the rectifiers.

The mAs timer is usually set to give the ___ mA at the ___ time. highest, highest highest, shortest lowest, shortest lowest, highest

The mAs timer is usually set to give the highest mA at the shortest time.

The three main parts of the x-ray imaging system are the x-ray tube, ____, and ____. protective barrier, tabletop operating console, high voltage generator rectification circuit, operating console crane assembly, tabletop

The three main parts of the x-ray imaging system are the x-ray tube, operating console, and high voltage generator.

The x-ray beam generated by the circuit with the ___ voltage ripple has the ___ quantity and quality.

The x-ray beam generated by the circuit with the lowest voltage ripple has the highest quantity and quality.

Which of the following waveforms has the highest efficiency? Three phase 6 pulse three phase 12 pulse single phase full wave all are equal

Three phase 12 pulse

Voltage across the x-ray tube is most constant with ____ high frequency generators single-phase, half-wave rectification single-phase, full-wave rectification three-phase, full-wave rectification

Voltage across the x-ray tube is most constant with high frequency generators.

With half-wave rectification, the current flows through the x-ray tube during the ___ part of the cycle. zero positive or negative positive negative

With half-wave rectification, the current flows through the x-ray tube during the positive part of the cycle.

The voltage in the x-ray circut is adjusted or fine tuned in the __________ for ease and safety.

autotransformer

Which of the following component receives power first in the x-ray circuit ? mA meter high voltage transformer rectifier autotransformer

autotransformer

At what point in the x-ray circuit is the rectification circuit located?

between the step-up transformer and the X-ray tube

The difference in the waveform between the primary and secondary sides of the high voltage transformer is ____. a. frequency b. velocity c. amplitude d. all of the above

c. amplitude

Which of the following timer types provides exposure times as low as 1ms?

electronic timer

A step-down transformer is located in the ___ circuit. tube timing filament rectifier

filament

The ____ circuit (transformer) provides electrons for the cathode within the x-ray tube.

filament

The negative side of the x-ray tube holds the ____. filament anode target rotor

filament

The ___ is the source of radiation in the x-ray tube. filament focal spot focusing cup stator

focal spot

All of the following are radiographer operated controls except

generator selection

The external structure of the x-ray tube includes the support structure, the protective housing, and the ___. anode cathode glass envelope focusing cup

glass envelope

A step down transformer has ______ windings in the secondary vs. primary side.

less

The operating console contains circuits that are ____. both high voltage and low voltage high voltage only low voltage only non-voltage

low voltage only *Easier and safer to fine tune at low voltage.

The rotating anode is turned by a ___.

magnetic field

The least accurate type of timer is the ____ timer. mechanical electronic synchronous mAs

mechanical

Thermionic emission at the filament determines the ___ across the x-ray tube during an exposure.

milliamperage

The autotransformer has ____ solenoid(s).

one

Which of the following generator types has the most voltage ripple? 3 phase 6 pulse 3 phase 12 pulse Single phase full wave High Frequency

single phase full wave

The x-ray generator with the lowest power rating is the ___ imaging system. high frequency three-phase, twelve-pulse three-phase, six-pulse single-phase

single-phase

Thermionic emission at the filament creates a ___. space charge grid control line focus heel effect

space charge When electrons are emitted from the filament, they create a cloud, called a space charge, in the vicinity of the filament before they are accelerated to the anode. (page 117)

Because of the line focus principal, the effective focal spot size decreases with decreasing ___. target angle rotor speed window thickness space charge

target angle *Line Focus Principle: By angling the target, one makes the effective focal-spot (useful beam) much smaller than the actual electron interaction on the anode sent from the cathode (page 122). The smaller the anode angle, the larger the anode heel effect. (page 123)

the most likely found incoming line current in a modern radiography system is: single phase power three phase power direct current ~ 60 volts

three phase power

The filament is made of ____. graphite tungsten copper molybdenum

tungsten

A filament transformer with a turns ratio of 1:20(secondary:primary) provides 3.1 amperes to the filament. What is the current flowing through the primary coil of the transformer?

x/3.1= 1/20 x/3.1=0.05 x=.155