Term
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Definition
multiple voltage waveforms are superimposed on one another, resulting in a waveform that maintains a nearly constant high voltage
voltage never drops to zero |
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Term
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Definition
when full wave rectification is applied to 3 phase current
produces voltage that can either be 6 or 12 pulse |
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Term
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Definition
ripple of 13-25%
voltage never drops below 75-87%
35% more average energy photons than single phase |
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Term
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Definition
has 12 diodes
ripple of 4-10%
voltage never drops below 90-96%
40% more average energy photons |
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Term
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Definition
uses AC and DC power converters to change the incoming line from 60 Hz- 6000 Hz
high frequency current is full wave rectified
peak kV is achieved in 10% of time necessary for 3 phase generators |
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Term
| advantages of 3 phase power |
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Definition
less voltage ripple
higher effective kV |
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Term
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Definition
| whenever there is a wire carrying an electrical current placed in a magnetic field, there is a force on the wire tending to push it out of the field |
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Term
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Definition
basic device for the measurement of current and voltage
consists of a coil of fine copper wire suspended between the poles of a horseshoe magnet |
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Term
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Definition
measures in amperes the quantity of electricity flow per second
connected directly to the circuit in series circuit |
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Term
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Definition
| measures in volts the differences of potential between any two points in a circuit |
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Term
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Definition
equipment is grounded to protect the xray specialist and patient from electrical shock
if live wire comes in contact with metal parts of equipment, current will flow directly to ground, no shock |
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Term
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Definition
equipment protection
connected in series along supply line to prevent overloading in circuits
made with metal tab that will melt in extreme heat to break the circuit
not reusable |
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Term
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Definition
equipment protection
permits breaking of circuit before dangerous temperatures are reached |
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Term
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Definition
two strips of different metals welded together
they react to temperatures by expanding, causing them to bend |
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Term
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Definition
an electromagnetic device operating on the principle of self induction
made up of a coil and an iron core inserted into it
the introduction of an iron core into the coil intensifies the magnetic field and increases the inductive reactance of the coil, producing
-a larger voltage drop
-a smaller remaining voltage
-a decrease in circuit |
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Term
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Definition
permits a variable contact to slide along a series circuit of resistant coils
can be used as a voltage regulating device |
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Term
| autotransformer (variable transformer) |
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Definition
regulates the voltage available to the primary side of the high voltage transformer
made of a single coil of insulated wire wrapped around a large iron core w/ insulation removed at regular intervals
acts on principle of self induction
single coil acts as the primary and secondary coils, with the number of turns being adjusted |
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Term
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Definition
| Vs/Vp= the number of tapped turns/ #of primary turns |
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Term
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Definition
part of xray circuit that modifies the incoming power to produce xrays
divided into primary (low voltage side) and secondary (high voltage side) |
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Term
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Definition
located on primary side
double blade single throw switch
designed to break connection with both hot lines simultaneously when activated
protects equipment and reduces fire hazard |
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Term
| autotransformers (main circuit) |
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Definition
| changes the voltage supplied to the primary side of the transformer to provide various kVs for the xray tube |
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Term
| kilovoltmeter (prereading kVp meter) |
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Definition
indicated desired kVp
reads voltage not kilovoltage |
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Term
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Definition
connected in parallel across portion of the primary side of autotransformer
detects fluctuations in line voltage due to variations in power distribution and consumption |
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Term
| xray transformer primary coil |
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Definition
connected to autotransformer by kV
coils immersed in transformer oil for insulation |
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Term
| timer and xray exposure switches |
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Definition
| control the current to the primary coil of transformer, completes exposure |
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Term
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Definition
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Term
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Definition
measure mA in xray tube
connected at center of of secondary winding of high voltage step up transformer |
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Term
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Definition
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Term
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Definition
| common connection of filament circuit and secondary circuit |
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Term
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Definition
| modifies the incoming line power to produce the thermionic emission from filament wire of xray tube by a series of devices |
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Term
| filament control device (mA selector) |
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Definition
| rheostat that can control xray tube current |
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Term
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Definition
| corrects for instantaneous fluctuations in line voltage that may be caused by momentary demand elsewhere on the line |
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Term
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Definition
| measures the filament current |
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Term
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Definition
automatically lowers filament current as kV is increased/ vice versa
enables tech to change kV without affect on mA |
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Term
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Definition
step down transformer
voltage supplied to filament lower than voltage supplied to filament transformer |
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Term
| xray tube (filament circuit) |
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Definition
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Term
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Definition
uses synchronous motor
cannot be used for serial exposures
min exposure time is 1/60 sec and intervals increase by multiples thereof |
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Term
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Definition
most sophisticated and efficient
allow for wide range of intervals as small as 1 ms |
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Term
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Definition
| special kind of electronic timer that terminates exposure when desired mAs is reached |
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Term
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Definition
uses a thyratron tube to regulate exposure automatically
xray beam- patient- table- cassette- fluorescent screen that absorbs xrays and emits light photons that are directed to a photo multiplier tube |
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Term
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Definition
type of automatic exposure control that incorporates a flat parallel plate ionization chamber between the patient and the film
IR is under ion chamber |
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Term
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Definition
| generators must terminate the exposures at 600 mAs for exposures above 50 kVp and 2000 mAs for exposures below 50 kVp (mammography) |
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