The xray circuit
What voltage ripple is associated with a three phase, twelve pulse generator.
4% A three phase, twelve pulse generator produces a 4% voltage ripple since the oscillating wave only falls 4% below 100% total energy
FInd the new voltage using the Transformer law formula: Secondary voltage = 100 Primary voltage = x Secondary turns = 50 Primary turns = 200
400 Volts Secondary voltage (100) x Primary turns (200) = 20,000 Secondary turns (50) x Primary voltage (x) = 50x 50x = 20,000 50 50 x= 400
A transformer with 100 wire windings on the primary side and 500 wire winding on the secondary side would have a ratio of
5:1 The transformer ratio is found by dividing the wire turns of the secondary side by the wire turns of the primary side. In this example, there would be 5 turns on the secondary side to every 1 turn on the primary side.
Which aspect of the x-ray circuit diagram below represents the autotransformer?
A Component A represents the autotransformer. This can be identified as the autotransformer because it has only a single wire coil. The autotransformer includes the kVp selector, which plays an essential role in converting the income line voltage to the correct kilovoltage within the x-ray tube.
Which component of the x-ray circuit operates on the principle of self-induction?
Autotransformer The autotransformer operates on the principle of self-induction. Self-induction is when a single wire coil serves as both primary and secondary portions of the transformer. The autotransformer modifies the voltage by electromagnetic induction within itself.
Which aspect of the x-ray circuit diagram below represents the low-voltage side of the step-transformer?
B Component B represents the low-voltage side of the step-up transformer. This can be identified as the low-voltage side because it has fewer coil turns compared to the other side of the transformer.
Where is the step-down transformer located with the x-ray circuit?
Between the milliamperage (mA) selector and the cathode filament The step-down transformer is located between the mA selector (rheostat) and the cathode filament. The step-down transformer must be located at this position in order to create the high-amperage necessary for thermionic emission to occur within the cathode filament.
Where are rectifiers positioned within the x-ray circuit?
Between the step-up transformer and the x-ray tube Rectifiers are located between the step-up transformer and the x-ray tube. The rectifier is placed here to convert the alternating current within the step-transformer to the direct current that supplies the x-ray tube.
Which aspect of the x-ray circuit diagram below represents the high-voltage side of the step-up transformer?
C Component C represents the high-voltage side of the step-up transformer. This can be identified as the high-voltage side because it has more coil turns compared to the other side of the transformer. At this stage in the circuit, the voltage has been converted to kilovoltage and has the necessary energy to create x-rays within the x-ray tube.
Which aspect of the x-ray circuit diagram below represents the secondary side of the step-up transformer?
C Component C represents the secondary side of the step-up transformer. The secondary side of a step-up transformer will always have more wire turns than the primary side.
Which aspect of the x-ray circuit diagram below includes the low-voltage portion of the step-up transformer?
Circuit A Circuit A (red) represents the low-voltage-portion of the step-up transformer, commonly called the primary circuit. The entire x-ray circuit is three interconnected circuits that each make essential contributions to the process of x-ray production. Included are the primary circuit (A), the secondary circuit (B), and the filament circuit (C).
Which aspect of the x-ray circuit diagram below represents the primary circuit?
Circuit A Circuit A (red) represents the primary circuit. The entire x-ray circuit is three interconnected circuits that each makes important contributions to the process of x-ray production. Included are the primary circuit (A), the secondary circuit (B), and the filament circuit (C).
Which aspect of the x-ray circuit diagram below represents the high-voltage portion of the x-ray system?
Circuit B Circuit B (blue) represents the high-voltage portion of the x-ray system. The incoming line voltage received by the primary circuit (A) is only 220 volts. Between the primary circuit (A) and the secondary circuit (B), the step-up transformer converts the low voltage current into the kilovoltage required by the x-ray tube within the secondary circuit (B). The secondary circuit is sometimes called the "high-voltage" portion of the circuit.
Which aspect of the x-ray circuit diagram below represents the secondary circuit of the x-ray system?
Circuit B Circuit B (blue) represents the secondary circuit of the x-ray system. The secondary circuit may be referred to as the high-voltage portion of the circuit because the circuit voltage was converted from volts to kilovolts.
Which aspect of the x-ray circuit diagram below represents the filament circuit?
Circuit C Circuit C (green) represents the filament circuit. The entire x-ray circuit is three interconnected circuits that each makes essential contributions to the process of x-ray production. Included are the primary circuit (A), the secondary circuit (B), and the filament circuit (C).
Which aspect of the x-ray circuit diagram below represents the high-amperage portion of the x-ray system?
Circuit C Circuit C (green) represents the high-amperage portion of the x-ray system. This is also called the filament circuit. The step-down transformer converts the incoming power supply from relatively low amps the high amperage necessary for the filament circuit. High amperage within the filament creates the heat necessary for thermionic emission to take place.
The large, solid part of the transformer is best know as the
Core The largest portion of the transformer is the core. The core is typically composed of iron and is where the tightly wound wire located.
Which aspect of the x-ray circuit diagram below represents a rectifier bridge?
D Component D represents a rectifier bridge. The rectifier bridge is located between the step-up transformer and the x-ray tube to convert the alternating current (AC) into direct current (DC). The step-up transformer requires AC while the x-ray tube is powered by DC.
Which aspect of the x-ray circuit diagram below represents the kVp meter?
D Component D represents the kVp meter. The power in this portion of the circuit is technically in volts, not kilovolts. The meter is placed here because volts are easier to measure, and the reading can easily be converted to kilovolts.
In the x-ray circuit diagram below, the electrical power at component E is described as:
High-amperage alternating current (AC) The electrical power at component E is high-amperage alternating current. Component E is the secondary side of the step-down transformer, which means the current has been modified to high amperage. There are no rectifiers in this portion of the circuit, so the waveform is still alternating current.
In the x-ray circuit diagram below, the electrical power at component C is described as:
High-voltage alternating current (AC) The electrical power at component C is a high-voltage alternating current. Component C is the high-voltage side of the step-up transformer, which means the electrical power has converted from volts to kilovolts. This is BEFORE the rectifiers, and the waveform is still alternating current.
In order to create a steady flow of highly penetrating x-rays, power arriving at the x-ray tube must be:
High-voltage direct current (DC) Power arriving at the x-ray tube must be both high-voltage and direct current (DC). High-voltage ensures that the tube creates x-rays with adequate penetrating ability. Direct current ensures that electrons only flow from cathode to anode and not in reverse.
What is the function of the step-down transformer within the x-ray circuit?
Increase current A step-down transformer decreases the voltage while at the same time increasing the current. A step-down transformer is placed in the filament circuit to create the high-amperage necessary to generate thermionic emission within the cathode filament.
Decreasing voltage ripple has what effect on image quality.
Increases Decreasing the voltage ripple increases image quality since low voltage ripples produce a more consistent x-ray beam.
A greater amount of wire windings on the primary side of the transformer will produce:
Less voltage Voltage is reduced when there is a greater amount of wire windings on the primary side as compared to the secondary side.
In order for a transformer to increase voltage it must have:
Less wire windings on the primary side A "step-up" transformer will have a greater amount of wire windings on the secondary side compared to that of the primary side.
In the x-ray circuit diagram below, the electrical power at component D is described as:
Low-amperage alternating current (AC) The electrical power at component D is low-amperage alternating current. Component D is the primary side of the step-down transformer, which means the current is still relatively low amperage. There are no rectifiers in this portion of the circuit, so the waveform is still alternating current.
In the x-ray circuit diagram below, the electrical power at component B is described as:
Low-voltage alternating current (AC) The electrical power at component B is low-voltage alternating current. Component B is the low-voltage side of the step-up transformer, which means the electrical power is still in volts and not kilovolts. This device is located BEFORE the rectifiers, so the waveform is still alternating current.
What technical factor controls the temperature of the cathode filament within the x-ray tube?
Milliamperage (mA) Milliamperage (mA) controls the temperature of the cathode filament. Increasing mA results in more current and more heat within the cathode.
Failure of the rheostat within the x-ray circuit would result in the inability to:
Modify the filament current Failure of the rheostat would result in the inability to modify the filament current. The filament current (mA) is directly controlled by the technologist through the rheostat (mA selector).
Failure of the autotransformer within the x-ray circuit would result in an inability to:
Modify the x-ray tube voltage Failure of the autotransformer would result in the inability to modify the x-ray tube voltage. The autotransformer includes the kVp selector, which plays an important role in converting the income line voltage to the correct kilovoltage within the x-ray tube. Without the autotransformer, the tube voltage would be fixed at 220 kilovolts.
Which aspect of the x-ray circuit is primarily responsible for controlling the voltage applied to the x-ray tube?
Primary Circuit The primary circuit is responsible for controlling the voltage supplied to the x-ray tube. The autotransformer and the step-up transformer modify the incoming line voltage before arriving at the x-ray tube. Both the autotransformer and the primary side of the step-up transformer are located with the primary circuit.
Which component of the x-ray circuit ensures that electrons flow in only one direction through the x-ray tube?
Rectifiers Rectifiers ensure that electrons flow in only one direction through the x-ray tube by converting alternating current (AC) into direct current (DC). With AC power, the electrons rapidly oscillate back and forth. With DC power, the electrons flow in only one direction.
The filament current is controlled by the technologist through a device called a(n):
Rheostat A rheostat serves as the mA selector and controls the filament current. As a thermostat controls the temperature of a house, the rheostat controls the temperature of the filament by modifying the filament current.
What type of transformer would have a turn ratio of 0.5:1?
Step-down Since the turn ratio is not a whole number, you can infer that the primary side has more wire turns than the secondary side. When there are more turns on the primary side, it is a step-down transformer.
Which component of the x-ray circuit operates on the principle of mutual-induction?
Step-up transformer The step-up transformer operates on the principle of mutual-induction. This is called mutual induction because there are two wire coils that serve as the primary and secondary portions of the transformer. The step-up transformer modifies the voltage by electromagnetic induction from one coil to the other.
Failure of the step-up transformer within the x-ray circuit would result in an inability to:
Supply adequate voltage to the x-ray tube Failure of the step-up transformer would result in the inability to supply adequate voltage to the x-ray tube. The step-up transformer converts volts into kilovolts. This device is essential because the incoming line voltage is only 220 volts, but the power arriving at the x-ray tube must be nearly 1,000 times higher in the kilovoltage range. Without increasing the voltage to kilovoltage, electrons within the x-ray tube would not have enough energy to create x-rays.
What term describes the process through which free electrons are created within the x-ray tube?
Thermionic emission Thermionic emission describes the creation of free electrons within the x-ray tube. "Therm" refers to heat, and "ionic" refers to charged particles like electrons. The term "thermionic emission" refers to the creation of charged particles (electrons) in response to heat.
Single-phase generators are inefficient since they produce waves that fall to zero before returning to 100%.
True This is true. The falling between zero and 100% causes there to be a short gap between X-ray photon production. This short gap means that a larger mAs must be used in order to produce a diagnostic x-ray beam.
The role of the transformer is to increase or decrease:
Voltage The transformers role within the X-ray circuit is to either increase or decrease voltage.
Which of the following devices is located within the filament circuit of the x-ray system?
mA selector The mA selector is located within the filament circuit. The mA selector must be located in this portion of the x-ray circuit as it is responsible for controlling the current supplied to the filament.
Which aspect of the x-ray circuit protects the system from power surges and short-circuits?
Circuit breaker The circuit breaker protects the rest of the x-ray circuit from power surges and short-circuits. The x-ray system could be damaged or destroyed if the system begins to draw too much power. The circuit breaker breaks the circuit and cuts off power to the entire x-ray system.
The rectifier's role within the X-ray circuit is to:
Convert AC to DC The role of rectification within the X-ray circuit is to convert alternating current (AC) to direct current (DC).
Which aspect of the x-ray circuit diagram below represents the mA selector (rheostat)?
D. D Component D represents the rheostat. The rheostat (mA selector) has an essential role in controlling the current supplied to the filament.
The autotransformer includes which of the following devices?
kVp selector The autotransformer includes the kVp selector. When the technologist sets the kVp, the initial change in voltage occurs when the kVp selector changes positions on the autotransformer. For example, if the technologists set the kVp to 100, the autotransformer modifies the incoming line voltage from 200 volts to 100 volts. Volts are converted to kilovolts at the step-up transformer.
Decreasing voltage to the filament circuit will result in: 1.Decreased thermionic emission 2. Increased electron production at the cathode 3.Increased thermionic emission 4.Decreased electron production at the cathode
2 & 3 When there is a decrease voltage in the filament circuit, there is an increase in current. Higher levels of current will result in a tungsten filament that reaches a higher temperature. This will cause more electrons to be burned off through thermionic emission. Both, b and c are correct.
The incoming line voltage received by most x-ray systems is:
220 volts The majority of x-ray systems are powered by an incoming line voltage of 220 volts. The transformers within the circuit modify this voltage so the correct kilovoltage is applied to the x-ray tube.
What voltage ripple is associated with full-wave rectification?
100% With full-wave rectification, the wave must fall to the zero line before reaching 100%. This 100% decrease in current causes the circuit to produce an 100% voltage ripple.
Which aspect of the x-ray circuit diagram below represents the circuit breaker?
. B Component B represents the circuit breaker. The circuit breaker must be placed at the very beginning of the x-ray circuit to protect the rest of the system from power surges and short circuits.
Which aspect of the x-ray circuit diagram below represents the primary side of the step-down transformer?
D Component D represents the primary side of the step-down transformer. The primary side always has more wire turns than the secondary side in a step-down transformer. This configuration decreases the voltage but increases the amperage. D. D Component D represents the rheostat. The rheostat (mA selector) has an essential role in controlling the current supplied to the filament.
With all factors remaining constant, a generator with 100% percent voltage ripple will have this effect on receptor exposure.
Decrease receptor exposure Generator with 100% voltage ripple are the least efficient at producing X-ray photons due to the wave form having to oscillate between 100% and 0%.
Select the term that describes the main component used within a rectifier(s)
Diode Diodes are the main component within rectifiers. Diodes work by allowing current to flow in only one direction.
This type of current must be delivered to the X-Ray tube for the production of photons to occur.
Direct Current (DC) Direct current is the only type of electricity that can be used in the production of x-ray photons. The use of alternating current would cause the x-ray tube current to flow in the wrong direction (anode to cathode not cathode to anode).
Which aspect of the x-ray circuit diagram below represents the exposure timer?
E Component E represents the exposure timer. The exposure timer controls the amount of time that power is supplied to the x-ray tube.
Which aspect of the x-ray circuit diagram below represents the x-ray filament?
E Component E represents the x-ray filament. The x-ray filament is the component responsible for creating free electrons through the process of thermionic emission.
At which point in the x-ray circuit diagram below has the electrical power been converted to high-voltage direct current?
E Location E, the x-ray tube, represents the only portion of the x-ray circuit that uses direct high-voltage current. Low voltage converts to high-voltage at the step-up transformer (B and C), and the alternating current converts to direct current at the rectifiers (D).
The amount of time the kilovoltage potential is applied to the x-ray tube is controlled by which of the following devices?
Exposure timer The exposure timer controls the amount of time the kilovoltage potential is applied to the x-ray tube. This is the same as the exposure time set by the technologist at the control panel.
A Transformers can only function through the supply of DC current.
False This is false, A transformer must have alternating current (AC) in order for mutual induction to occur.
Diodes are able to be placed within a rectifier in either direction based on the incoming current.
False This is false. A diode can only be placed in one direction since diodes allows current to pass in only one direction
The step-down transformer is located in the:
Filament circuit The step-down transformer is located in the filament circuit. In order to increase the current necessary for the desired level of thermionic emission in the filament, there needs to be a decrease the voltage. This is done with a step-down transformer. Remember, when there is a decrease in voltage, there is an increase of current.
The removal of the bottom, negative oscillating wave is known as?
Half-wave rectification The term, "half-wave rectification" describes the removal of the negative oscillating wave that is present in alternating current (AC).
In order to create sufficient heat within the cathode filament, the power supplied to the filament must be:
High amperage High amperage is necessary to create sufficient heat within the cathode filament. This heat is necessary to generate the process of thermionic emission.
The step-up transformer in the x-ray circuit serves to modify the current within the x-ray system by converting:
Volts to kilo-volts The step-up transformer converts volts into kilovolts. This device is important because the incoming line voltage is only 220 volts, but the power arriving at the x-ray tube must be nearly 1,000 times higher in the kilovoltage range. Without increasing the voltage to kilovoltage, electrons within the x-ray tube would not have enough energy to create x-rays.
