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What is the wave equation?
Velocity = frequency x wavelength
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If frequency increases, then wavelength _______
decreases
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If frequency decreases, then wavelength _________
increases
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What is defined as the number of wave forms per second?
Frequency
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Frequency is a representation of _______
energy
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X-ray photons are about __ cycles per second
10^19
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As beam energy is increased, frequency ______
increases
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Beam energy is determined by what?
kVp
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The higher the kVp, the _____ the ________ (there are 4)
- the higher the photon frequency
- the higher the beam quality
- the harder the beam
- the higher the penetrability of the beam
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Higher energy photons act like what?
- particles
- note: if they hit something, they do damage
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Low energy photons act like what?
- waves
- note: they just bump into things. takes a lot to do damage
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An electric current is induced in a circuit if part of the circuit is in a changing magnetic field. A magnetic field can be generated by alternating magnetic fields. This is known as what?
Faraday's Law
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Transformers work with __ current through the application of Faraday's Law.
AC-alternating current
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The goal of a step-down transformer is?
- To decrease the incoming voltage and increase current.
- ***They work on the principle of mutual induction
- ***Allows for thermionic emission to occur at the filament
- ***Ultimately, provides the electrons necessary for x-ray production.
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Which side of the step-down transformer has fewer windings?
Secondary side
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The goal of a step-up transformer is?
To increase the voltage
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Which side of the step-up transformer has more wires?
- Secondary side
- ***therefore a higher voltage is produced
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Which side of the step-up transformer does the voltage come in?
Primary side
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What are 2 other names for the step-up transformer?
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What has only one winding and works on the principle of self-induction?
autotransformer
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What are the 3 types of transformers?
- Closed-core transformer
- Autotransformer (single)
- Shell-type transformer
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What gets transformed in a transformer?
Voltage and current
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What are the 3 sections of the x-ray circuit
- Operating (control) console
- High voltage generator
- X-ray tube
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What addresses the issue of the divergent beam?
- Inverse Square Law
- ***As the beam travels it diverges or spreads out. The further it travels the more spread out it becomes, however, the intensity will be diminished
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What are conditions that are necessary for x-ray production?
- High voltage-in the kilovolt range
- Electrons-a supply of electrons and a need to stop the electrons suddenly
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How do transformers work?
- The can only work using AC current
- On the principle of induction - mutual and self
- The basic premise is that the AC current "induces" alternating magnetic fields in loop (coils) of wire
- These alternating magnetic fields are distributed throughout the core of the transformer
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What is the conservation of energy?
When voltage is increased, the current decreases
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Which side of the step-down transformer has more coils?
- The primary side
- ***This results in a decrease in voltage through the transformer
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What consists of the operating (control) console?
- Line voltage compensator/monitor
- Autotransformer
- kVp selector
- mA selector
- Timer
- Pre-reading kVp meter
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What is the purpose of the line voltage compensator?
To maintain a constant voltage to the system. In the modern system this is done automatically
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The autotransformer works on what principle? Is it a step- up or step-down transformer or both?
- The autotransformer works on the principle of self-induction. It has a single core and is responsible for varying the voltage.
- Because of its ability to adjust voltage, the autotransformer can be either a step-up or step-down transformer.
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Where is the kVp adjusted at?
The autotransformer
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Why is the kVp meter considered pre-reading?
- •The kVp meter is considered pre-reading because it is not actually measuring kVp but measuring voltage off the autotransformer.
- ***Remember, the autotransformer is used to adjust voltage.
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What types of electronic timers are out there as of today?
- mAs
- Phototiming (AEC)
- Regular electronic
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What does the mA selector do?
- Allows for adjust of the filament voltage
- ***Precision resistors
- ***Choke coil
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What is another name for the step-down transformer?
Filament transformer
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What is the purpose of the retifier?
To allow electrons to flow in only one direction
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How many retifiers are required to fully convert AC to DC?
4 retifiers
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Rectifiers convert __ to __ current
AC to DC current
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What are the types of circuits?
- Single phase
- Three phase
- Medium and high frequency
- Capacitor discharge
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What consists of the single phase?
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What consists of the three phase?
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What do the three phase units use for transformers?
Delta and 'wye'
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In a three phase transformer, the 6 pulse uses what and how many transformers?
2 'wye' and 1 delta
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In a three phase transformer, the 12 pulse uses what and how many transformers?
2 delta and 1 'wye'
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Three phase transformers require how many rectifiers?
12 retifiers
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What are the advantages of three phase?
- Higher beam quantity and quality
- Higher mA stations are also possible
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Why higher quantity and quality for three phase?
- Because the voltage ripple is less
- ***Basically when the tube is energized it stays energized.
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The turns ratio for the step-up transformer is:
500:1 or 1000:1
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