X-ray Circuit: Secondary Circuit Explained

Introduction to the X-ray Circuit

• This lesson is the second in a series concerning the X-ray circuit, specifically focusing on the secondary circuit.

Structure of the X-ray Circuit

• The complete X-ray circuit is composed of three combined circuits:
  • Primary Circuit: Involved in the initial energy provision.
  • Secondary Circuit: The focus of this lesson, responsible for converting and directing power to the X-ray tube.
  • Filament Circuit: Powers the filament of the X-ray tube.

Understanding the Secondary Circuit

• Definition of the Secondary Circuit:
  • It is called the secondary circuit because it operates on the secondary side of a transformer.
  • It directly influences the operation of the X-ray tube, which is crucial for X-ray production.
• Function of the Transformer:
  • The step-up transformer converts voltage from volts to kilovolts.
  • This conversion is essential since the X-ray tube functions on kilovoltage, not volts.

Role of Current Types in the X-ray Circuit

• AC vs. DC Current:
  • Transformers operate using Alternating Current (AC), allowing AC power to be stepped up in voltage.
  • The X-ray tube, however, requires Direct Current (DC) for its operation.
• Consequences of Using AC in the X-ray Tube:
  • If an AC current were used within the X-ray tube, electrons would flow in both directions (cathode to anode and back), leading to malfunction.

Rectification Process

• Rectifiers:
  • Essential components that convert alternating current (AC) into direct current (DC). They ensure that electrons travel solely in one direction.
  • The symbol for a rectifier features arrows indicating a unidirectional flow of current.
• Rectifiers in Action:
  • AC from a transformer has reversing polarity, enabling electrons to move in alternating directions.
  • Upon entering the rectifiers, the current transitions to having only one polarity, thereby allowing electrons to consistently flow in one direction, meeting the operational needs of the X-ray tube.

Components of the Secondary Circuit

• The secondary circuit comprises three primary elements:
  • Step-up Transformer:
    • Operates on AC current.
    • Responsible for converting volts to kilovolts (e.g., $V{input} = V{output} imes rac{N{secondary}}{N{primary}}$).
  • Rectifiers:
    • They provide the critical function of converting AC into DC, positioning themselves between the transformer and the X-ray tube to facilitate this transition.
  • X-ray Tube:
    • Receives the kilovoltage at DC to transform the flow of electrons into X-rays. It is designed to operate specifically on a DC current.

Conclusion

• Understanding the transitions between AC and DC within the secondary circuit is pivotal for grasping how the X-ray production process functions effectively. The interactions among the transformer, rectifiers, and the X-ray tube form a cohesive system that is essential for producing X-rays.