Physic Ch.6 Study Guide

• What is the main topic of Chapter 6 in T. Parker's Study Guide?

  1. Ray Imaging System
• What are the key components of an X-ray imaging system?

  • Circuits
  • Sections
  • Components
• What are the two types of rectification in X-ray imaging?

  1. Half-wave rectification
  2. Full-wave rectification
• What is a diode in the context of X-ray circuits?

  A one-way electrical device used to rectify the x-ray circuit
• What does voltage ripple refer to?

  Fluctuations in the voltage waveform
• What are the characteristics of half-wave rectification?

  • Uses only the positive half of the AC waveform
  • Removes the negative half of the AC waveform
  • Requires 1-2 diodes
  • X-ray output = 60 pulses per second
  • Disadvantage: wastes half of the power and requires twice the exposure time
• What are the characteristics of full-wave rectification?

  • Converts the entire AC waveform into direct current (DC)
  • Uses both positive and negative portions of the AC cycle
  • Requires 4 diodes
  • X-ray output = 120 pulses per second
  • Advantages: requires half the exposure time; no large gap in power supply
  • Disadvantages: has pauses in the power supply
• What is the formula for calculating the turns ratio in transformers?

  Turns ratio = primary turns / secondary turns

  
• What voltage and frequency supply the X-ray imaging system?

  60 Hz & 110 V
• What is the function of the circuit breaker in the X-ray system?

  Protects against short circuits and shock hazards
• What does the line monitor do in the X-ray system?

  Measures the incoming line voltage & current
• What is the role of the line compensator in the X-ray system?

  Adjusts the incoming voltage to 220V and corrects fluctuations
• What is the function of the autotransformer in the X-ray system?

  • First component to receive power
  • Provides power to secondary and filament circuits
  • Supplies precise voltage needed by transformers
  • Single winding & one core with primary and secondary connections
  • Voltage is related to the number of turns
• What does the kVp selector do in the X-ray system?

  Provides the required kilovoltage to the imaging system
• What are the two types of kVp selectors?

  • Major kVp selector: adjusts by factors of 10
  • Minor kVp selector: fine-tunes by factors of 1-2
• What is the purpose of the exposure timer in the X-ray system?

  Controls exposure time by terminating the x-ray exposure
• What are the four types of timer circuits in the X-ray system?

  1. Synchronous
  2. Electronic
  3. mAs
  4. Automatic exposure control (AEC)
• What does the mA selector do in the X-ray system?

  Adjusts the flow of current by varying resistance in the circuit
• What is the function of the high-voltage transformer?

  • Step-up transformer
  • Raises volts to kilovolts
  • Increases voltage 500-1000 times
• What is the role of the filament transformer?

  • Step-down transformer
  • Provides current to heat the filament
  • Lowers voltage and raises current
• What does the focal spot selector do in the X-ray system?

  Corresponds to the filaments of the x-ray tube
• What are the characteristics of the mA meter?

  • Monitors the x-ray tube current
  • Provides accurate readings before, during, and after exposure
• What is the function of rectifiers in the X-ray system?

  • Changes AC to DC
  • Allows current to flow in one direction
  • Acts as an insulator when AC current reverses
• What are the types of generators used in X-ray systems?

  1. Single-phase generators
  2. Three-phase generators
  3. High frequency generators
  4. Capacity generators
  5. Falling load generators
• What are the characteristics of single-phase generators?

  • Generates one AC waveform
  • 100% voltage ripple
  • Produces less penetrable x-rays
• What are the advantages of three-phase generators?

  • Maintains near constant voltage
  • Produces more penetrable x-rays
  • Requires less ripple
• What is the output of a 3-phase/6 pulse generator?

  • Uses 6 diodes
  • 13-14% voltage ripple
  • X-ray output = 360 pulses per second
• What is the output of a high frequency generator?

  • Converts AC power from 500 Hz to 25,000 Hz
  • Produces < 1% ripple
  • X-ray output = 500-1000 pulses per second
• What is the definition of voltage ripple?

  • Fluctuations in the voltage waveform
  • Results in a pulsating x-ray beam
• What are the types of timers used in X-ray systems?

  1. Synchronous timers
  2. Electronic timers
  3. mAs timers
  4. Automatic Exposure Control (AEC) timers
• What is the function of AEC in X-ray systems?

  • Determines exposure time
  • Automatically stops exposure when the IR receives enough radiation
• What are the two types of AEC systems?

  1. Ionizing chambers (modern)
  2. Phototimer (older)
• What is the minimum exposure time for synchronous timers?

  1/60 or 17 milliseconds
• What is the advantage of electronic timers in X-ray systems?

  Most complex and accurate timers
• What does the mAs timer do in the X-ray system?

  Monitors mAs and terminates exposure when desired mAs is reached
• What is the purpose of the back-up timer in AEC systems?

  Set to 1.5 times the expected exposure time in case of timer failure
• What is the significance of the actual time and total mAs displayed after an exposure?

  • Provides feedback on exposure settings
  • Helps in adjusting future exposures