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124 Cards in this Set
- Front
- Back
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Name the 3 parts of the X-ray system.
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x-ray tube, console, high voltage
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How many windings does the autotransformer have?
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1 winding
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What provides electrons for the x-ray tube current?
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the filament circuit
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Where is a step down transformer located?
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filament circuit
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What do diodes do?
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allows electrons to flow from cathode
to anode |
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what is the most accurate type of timer?
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electronic
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What is the first component to receive power in the x-ray
tube? |
autotransformer
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What corrects the varying voltage input to the x-ray
machine? |
line voltage compensator
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Electric circuits that connect the meter and controls on the
operating console are _______ voltage? |
low
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What are the 3 main parts of the high voltage generator?
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high voltage transformer, Filament transformer and Rectifier
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What is the release of electrons from the filament called ?
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thermionic emission
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What does the release of electrons from the filament
determine??????????????????????????????????? |
The milliamperage across the x-ray tube
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This provides the highest safe tube current for the shortest
exposure? |
mAs timer
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How much does the step up transformer increase the
voltage? |
500-1000 times
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What is the purpose of the AEC?
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to terminate the exposure when enough radiation has reached the IR
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What is the only difference of the wave form between the primary and the secondary side of the high voltage transformer?
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the amplitude
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When a cloud of electrons gather around a heated
filament? |
space charge effect
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What is rectification?
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process of converting AC to DC
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What are the components of the rectifier made up of?
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solid state semiconductors
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In half wave rectification, when are the electrons allowed
to flow? |
in the positive cycle
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In full wave rectification, what occurs to the negative cycle of the wave form?
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it's reversed so that the anode is always positive
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How many pulses does a rectified full wave machine put
out per second? |
120 pulses / second
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How many pulses does a rectified full wave 3 phase
maching put out/sec? |
360 pulses/sec
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The voltage applied across the x-ray tube is most constant
with _________________. |
high frequency generators
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What type of generator does a mommography unit and a
spiral CT unit operate on? |
high frequency generator
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What is the ripple amount for a single phase machine?
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100 %
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What is the ripple amount for a three phase 6 pulse
machine? |
14%
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What is the ripple amount for a three phase 12 pulse
machine? |
4%
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What is the ripple amount for a high frequency generator
machine? |
1%
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What is the most efficient method of x-ray production?
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high frequency generators
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Whats one main disadvantage of 3 phase power?
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very costly
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The x-ray generator with the highest power rating has the
lowest what? |
ripple
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What is the formula for calculating high voltage
generators? |
Power= Max tube current(mA)
@ 100 kVp and 100 ms |
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What is the x-ray generator with the lowest power rating?
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single phase
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the operating consoles consits of what ?
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1: an on and off control.
2: controls to select kVp, mA, and time or mAs 3: AEC |
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the high-voltage generator provides power to the x-
ray tube in three possible ways, what are they ? |
1: single phase power
2: three phase power 3: high-frequency power |
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what is the diffance between single and three phase
power? |
the manner in which the high-voltage step-
up transformer is electrically positioned |
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What phase of power is the voltage across the x-ray tube
nearly constant during exposure and never drops to zero? |
three-phase power
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the components of an x-ray imaging system is
sometimes identified by there power rating in what unit? |
kilowatts (kW)
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the operating console is used for what ?
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1: control the voltage applied to the x-ray
tube. 2: control the current through the x-ray tube. 3: control the exposure time. |
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the high-voltage generator contains what ?
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the high-voltage step-up transformer,
the rectification circuit and filament transformer. |
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differant types of x-ray imaging systems are usually
identified by what ? |
identified according to
- the energy of the x-rays they produce - or the purpose for which those x-rays are intended. |
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there are many different diagnostic imaging systems ,
these systems operate at voltage of __ to __ kvp and tube currents of __ to __ mA. |
25 to 150 kVp 100 to 1200 mA
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a fluoroscopic table is identified by what and located where?
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the degree of the head and foot tilt and is located under the examination table.
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what are the advantages of carbon fiber table tops ?
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they are strong and absorb little x-radiation that will reduce patient dose.
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name the 5 types of timing circuits
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1: mechanical
2: synchronus 3: mAs 4: AEC 5: electronic |
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what has a single winding and is designed to supply a
precise voltage to the filament circuit and to the high-voltage circuit of the x-ray imaging system? |
autotransformer
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what determines the quality of the x-ray beam ?
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kVp
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what is the release of electrons from a heated
filament? |
thermionic emission
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the poduct of x-ray tube current (mA) and exposure
(s) is mAs, which is also called what ? |
electrostatic charge (C)
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what are used on falling-load and capacitor discharge
imaging systems? |
mAs timers
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what is the process of converting AC to DC ?
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rectifiers (rectification )
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what is used when medical imaging systems are
described? electron flow or current flow? |
electron flow
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less voltage ripple results in ____ radiation quanity
and quality. |
greater
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during capacitor discharge, the voltage falls approximately ?
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1 kV/mAs
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high -voltage generators power (kW) = maximum x-ray tube current (mA) at __ kVp and __ ms.
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100kVp 100ms
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power =
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current x potential
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watts =
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amperes x volts
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power rating (kW) = mA x kVp / 1000
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equation for three phase and high-frequency power
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single phase power equation
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power rating (kW) = (0.7) mA x kVp / 1000
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what is the voltage ripple for a single-phase power ?
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100% voltage
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what is the voltage ripple for a three-phase, twelve-pulse power ?
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4% voltage
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what is the ripple voltage for a three-phase , six-pulse power?
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14% voltage
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what is the ripple power for a high frequency generator ?
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1% voltage
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___ ___ rectification or __ ___ voltage generators is used in almost all stationary x-ray imaging system.
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full-wave rectification and high-frequency voltage
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fluoro x-ray tubes are usually located where ?
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under the table
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the radiographic x-ray tube is attached to what ?
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an overhead movable crane.
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a patient supporting examination table is required to be __ or __ but must be uniform in __ and __ to x-
rays. |
flat or curved. thickness and transparent
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if the table is used for fluoro where should the tray be
located ? |
the tray must be moved to the foot of the
table and the opening must be shielded from radiation |
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x-ray tube current is controlled through separte circuit
called what ? |
filament circuit
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filaments operate at currents of what?
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3 to 6 amperes
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the number of electrons emitted by the filament is
determined by what? |
the temperature of the filament
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the tube current, crossing from cathode to anode in
measured in what? |
mA
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the kvp prereading allows what ?
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the voltage to be monitored before exposure
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the kvp meter that is across the output terminals of the
autotransformer is called what ? |
prereading kvp
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the operating console allows the radiologic tech to control what?
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tube current and voltage, so the useful x-ray beam is for proper quantity and quality
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the operating console provides what?
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controls of line compensation , kVp , mA, and exposure time.
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x-ray imaging systems are designed to operate on
what power? |
220 V
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what measures and adjusts the voltage to precisely
200 V? |
line compensator
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the power supplied to the x-ray system is delivered
first to what? |
autotransformer
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the autotransformer works on the principle of what?
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electromagnectic induction
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the autotransformer is designed to do what ?
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step up voltage to approximately twice the input value
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the kvp meter that is across the output terminals of the
autotransformer is called what ? |
prereading kvp
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the tube current, crossing from cathode to anode in
measured in what? |
mA
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the number of electrons emitted by the filament is determined by what?
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the temperature of the filament
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We can calculate the output current of a transformer using the following formula:
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Ip/Is = Ns/Np
(Where I represents current, N is the number of turns, s is secondary coil, and p is primary coil.) |
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Which transformer serves as a kVp selector?
a. step up transformer b. step down transformer c. autotransformer |
c. autotransformer
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A rheostat is located in which circuit?
A. Primary B. Secondary C. Filament D. Circuit breake |
C. Filament
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The rheostat controls which of the following in the filament circuit?
A. Current B. Voltage C. Resistance D. Temperature |
C. Resistance
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The technologist has direct control of the resistance in the filament circuit through which setting on the control panel?
A. kV selector B. Focal spot selector C. AEC D. mA station |
D. mA station
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Why are rheostats necessary in the x-ray production process?
A. Control anode temperature B. Control filament heating C. Adjust kV D. Select focal spot |
B. Control filament heating
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The exposure timer serves what purpose in the general x-ray circuit?
A. Controls duration of filament heating B. Controls kV output C. Monitors radiation output D. Monitors x-ray tube temperature |
A. Controls duration of filament heating
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Which exposure timer is based on how fast a motor turns a shaft?
A. Electronic timer B. AEC C. Synchronous timer D. mAs timer |
C. Synchronous timer
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Which component increases voltage about 500 times?
A. Step-up transformer B. Rectifier C. Rheostat D. Filament |
A. Step-up transformer
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Which component serves to route electricity through the x-ray tube in the same direction each time?
A. Step-down transformer B. Rheostat C. Rectifier D. Autotransformer |
C. Rectifier
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Which sections provide the kinetic energy needed to produce x-rays?
1. primary 2. secondary 3. filament A. 1 and 2 only B. 2 and 3 only C. 1 and 3 only D. 1, 2, and 3 |
A. 1 and 2 only
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Which number on the illustration corresponds to the secondary circuit?
A. 1 B. 2 C. 3 |
B.2
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Which number on the illustration corresponds to the filament circuit?
A. 1 B. 2 C. 3 |
C. 3
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The autotransformer is a part of which circuit?
A. Primary B. Secondary C. Filament D. Circuit breaker |
A. Primary
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Hysteresis losses result in changing magnetic fields and can be reduced by using core material that is more _______.
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permiable
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Copper losses are from reistance to current flow and can be reduced by ______.
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larger diameter wire.
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EMF stands for ?
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Electro Magnetic Force
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What is the maximum time for the back up timer?
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6 seconds
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Which support design is most common for the x ray tube?
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ceiling mount (overhead imaging system)
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Another name for mAs is ______ charge (C).
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electrostatic
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Rectifier banks are located in which circuit?
A. Primary B. Secondary C. Filament D. Circuit breaker |
B. Secondary
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___ ______ are used on falling-load and capacitor discharge imaging systems.
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mAs timers
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Most exposure timers are electronic and are controlled by a __________.
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microprocessor
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Solid-state radiation detectors are used to check _______ accuracy.
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timer
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Solid state rectifiers are made of ______.
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silicon
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What is this?
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THE FLUX CAPACITOR, MARTY !!!!
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1200 mA is equal to __ amps
12 1.2 .12 .012 |
1.2
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Single phase full wave rectification involves the use of ___ diodes in the circuit in order to convert AC to DC.
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4 diodes
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the operating console contains circuits that are ____ in order to reduce electric shock potential .
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low voltage only
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The waveform of current that has been rectified is sometimes referred to as
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pulsating direct
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High frequency converts full wave rectified power from 60 Hz to as much as ____ Hz
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500 +
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In order for electrons to cross the p-n junction of a semiconductor, the charge on the P side must be
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Positive
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60 Hz AC current changes direction ____ each second.
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120
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The term "min reaction (response) time" relates to ____.
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AEC
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"Self rectification" corresponds with ______ .
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half wave rectification
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Imaging techniques may be reduced by ___ kVp when using three phase rather than single phase generated power.
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15 kVp
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which units correspond to Power?
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Watts
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voltage exiting the step up transformer will next pass through the _____
Rheostat Rectifier X ray tube Autotrasformer |
Rectifier
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which movement of a 90/20 table places in the trendelenberg position?
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20
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