chapter 5 bushong
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| What are the 3 main components of the imaging system? | operating console, high voltage generator,tube
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| what is the operating console used to control? | The quality and quantity of x-ray beam
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| What type of transformers are in the high voltage generator? | a step up and a step down transformer
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| what 4 functions does the operating console allow you to control? | current (mA), voltage (kvp), exposure time, line compensation
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| why do electric circuits and meters connected to the console operate at low voltages? | to minimize possible shock hazzards
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| most x-ray imaging systems work on 220v but some can operate at _______ or ________ | 110v/440v
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| what does the line voltage compensator measure? | The voltage provided to x-ray imaging system
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| what does the line compensator adjust the voltage to? | 220v
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| what is known as the "orchestrator" in the console? | autotransformer
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| what is the auto transformer responsible for? | accepting, controlling and delivering low voltage power to the high voltage power to the high voltage/ step up transformer
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| what is usually the in put to the auto transformer? | 220v
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| what is the output of the autotransformer? | usually controllable between 100-400v
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| on an autotransformer what is the primary connections responsible for? | conducting the input power
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| what is the secondary connection of the autotransformer responsible for? | serve to either increase or decrease the voltage depending on where they are located along the winding
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| what type type of induction is the autotransformer? | self induction
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| what are taps on the autotransformer? | places where voltage exits the transformer
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| In autotransformer law what is the relation between voltage and turns ratio? | directly proportional
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| In autotransformer law what is the relation between current and voltage? | inversely proportional
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| what are the 2 kvp options on some older models? | major and minor
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| what does voltage leaving the autotransformer become? | input to the high voltage transformer
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| which side of the autotransformer is the kvp meter on? | secondary side
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| which side of the high voltage generator is the kvp meter on? | primary side
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| What is the kvp meter responsible for reading? | total voltage leaving the autotransformer before it reaches the high voltage transformer
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| What controls tube current from cathode to anode? | mA
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| The number of electrons produced through thermionic emission is determined by? | The temperature of the filament
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| what does filament current operate at? | 3-6A
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| if tube current works on 3-6 amperes what is the range in milliamperes? | 3,000-6,000 milliamperes
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| where is the filament circuit located? | along the autotransformer
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| what does the filament circuit control? | tube current
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| What is placed along the filament circuit in order to control current and create mA station? | precision resistors (or rheostats)
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| Once a mA station had been selected ,voltage travels from the mA selector switch to the_______ | filament transformer
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| Is the filament transformer a step up or step down transformer? | step down
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| what is the official name for the filament transformer? | filament heating isolation step down transformer
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| Why are the secondary windings heavily insulated on the filament transformer? | because it is connected to the high voltage supply for the x-ray tube
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| whats the difference between the primary and secondary windings on the filament transformer? | primary are thin copper and secondary thick copper
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| what is the range that the primary windings on the filament transformer carry? | .5-1A and 150 v
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| what is the range that the secondary windings on the filament transformer carry? | 5-8A and 12v
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| what does the mA meter monitor? | tube current
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| where is the mA meter? | at the center of the secondary winding of the high voltage transformer in the x-ray tube circuit
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| where are most exposure timers? | on the secondary side of voltmeter and primary side of high voltage transformer
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| what does an exposure timer control? | how long current runs through the filament
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| what is the name of a safety feature that will terminate exposure at a designated time. (~6 sec) | guard timer
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| what type of timer cannot make serial exposures because it has to be manually reset after each exposure? | synchronous timers
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| what type of timer allows for serial exposures? | electronic timers
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| what is designed to provide the highest safe tube current for the shortest time possible? | mAs timers
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| what side of the high voltage transformer is the mAs timer on? | secondary side
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| A device that measures the quantity of radiation that reaches the IR and cuts off exposure when appropriate | AEC
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| where are AEC's located? | between the patient and the IR
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| what type of timer is the AEC used in conjunction with? | electronic timer
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| back up timer should be set to _____x's the expected time | ~1.5
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| what type of image will you get in the timer for the AEC is too short? | a light image
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| what will happen if the timer for the AED is too long? | it will add unnecessary dose to the patient and a dark image
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| what are the 2 types of AEC devices? | Ionization chambers and photomultiplier tube
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| what is in the AEC chamber of a photomultiplier tube? | a small photocathode tube
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| what are the 3 primary parts of a high voltage generator? | high voltage transformer, filament transformer and rectifiers
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| what does a high voltage generator do to output voltage from the autotransformer? | increases it to the appropriate KVp needed for x-ray production
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| what are 2 reasons the high voltage generator contains oil? | for insulation and to conduct heat from the high voltage section
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| The turns ratio is usually between ____ or ______ for a high voltage transofrmer | 500:1 /1000:1
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| what is voltage and current measured in on the primary side of the high voltage transformer? | voltage-V
current-A
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| what is voltage and current measured in on the secondary side of the high voltage transformer? | voltage-KVp
current-mA
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| what type of current is required for the x-ray tube function appropriately? | direct current
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| What is the purpose of a voltage rectification? | to convert current from AC to DC
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| What are rectifiers? | electronic devices that contain diodes
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| What are diodes? | solid state electronic devices that are made of silicon or selenium and contain 2 electrons
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| what do rectifiers in a circuit determine? | how little or how much voltage is produced
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| how many diodes does half wave rectification contain? | 1 or 2 diodes
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| how many pules per second are produced by a half wave rectification? | 60 x-ray pulses per second
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| how many diodes does a full wave rectification have? | at least 4 diodes in the high voltage circuit
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| how many pulses per second are produced by a full wave rectification? | 120 x-ray pulses per second
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| what do the arrows in the diode indicate? | the direction of the current
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| what type of x-ray beam does a single phase generator produce? | pulsating x-ray beam
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| what type of generator results in 6 pulses per 1/60 sec or 360 per second? | three phase generators
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| what type of generator produces nearly constant potential voltage waveform. | high frequency generator
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| what is the voltage ripple % for 1 phase? | 100% ripple
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| what is the voltage ripple % for 3 phase and 6 pulse? | 14% ripple
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| what is the voltage ripple % for 3 phase and 12 pulse? | 4% ripple
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| what is the voltage ripple % for high frequency? | <1% ripple
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| what is the disadvantage of low ripple? | cost
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| A benefits of low ripple is ___ dose to the patient because less technique is need for the same image | less
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| What are two equations for power rating? | P=IV or W=AV
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| What is power rating expressed in? | kW
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