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Study Notes on X-ray Primary Circuit

Introduction to X-ray Circuit

  • This lesson is the first in a series about the X-ray circuit, focusing specifically on the primary circuit.
  • The complete X-ray circuit consists of three combined circuits:
    • Primary circuit
    • Secondary circuit
    • Filament circuit
  • Each circuit supports X-ray production in unique ways.

Overview of the Primary Circuit

  • The primary circuit is where the main power supply enters the X-ray machine.
  • It is referred to as the primary circuit because it exists on the primary side of the step-up transformer.
  • The primary circuit consists of several significant components critical to the functioning of the X-ray machine.

Major Components of the Primary Circuit

Circuit Breaker

  • Definition: The circuit breaker is among the first components in the primary circuit.
  • Purpose: It serves to protect the rest of the circuit by breaking the circuit if the machine attempts to draw too much power.
  • Functionality:
    • When triggered, it stops incoming electrical power from reaching the X-ray machine.
    • This prevents potential damage to the circuit from excess electrical power.

Primary Exposure Factors

  • The primary circuit directly relates to the primary exposure factors essential to X-ray production, particularly the kilovoltage potential (kVp).
  • Incoming electrical power is initially at 220 volts, which is insufficient for X-ray generation.
  • Higher voltage settings, specifically kilovolts, are required in radiography.

Auto Transformer

  • Function: The auto transformer plays a crucial role in adjusting the kVp settings for the X-ray machine.
  • Operation:
    • It utilizes a single coil of wire through a mechanism known as self-induction.
    • The term "auto" implies self or one, indicating its singular coil configuration.
    • The adjustment of kVp is facilitated by this device, changing voltage from volts to the required kilovolts.

kVp Meter

  • Placement: The kVp meter is located subsequent to the auto transformer in the primary circuit.
  • Rationale:
    • The meter measures voltage in volts, which is easier to read compared to kilovolts.
    • Readings in volts can easily be converted to kilovolts for accurate kVp measurement.

Exposure Timer

  • Function: The exposure timer is integrated within the primary circuit to control the duration of the exposure.
  • Justification: Since the primary circuit governs kVp, it's logical for the timer to be placed here to synchronize exposure length with voltage settings.

Step-Up Transformer

  • Definition: The last component in the primary circuit is the step-up transformer, specifically on its primary side.
  • Purpose: This part of the circuit converts electricity from volts to kilovolts to meet the operational requirements for X-ray production.
  • Mechanism: It operates on the principle of mutual induction using a set of two coils:
    • Red coil and blue coil.
    • Notable: The blue coil has more turns than the red coil, indicative of the voltage being stepped up to kilovolts.
  • Spatial Arrangement: The area between the two coils demarcates the boundary between the primary and secondary circuits.

Summary of the Primary Circuit Components

  • Main Power Supply: Receives the primary voltage necessary for X-ray generation.
  • Circuit Breaker: Protects the circuit from excess electrical power.
  • Auto Transformer: Allows selection of desired kVp by employing self-induction with a single wire coil.
  • kVp Meter: Measures voltage in volts for easier reading and conversion.
  • Exposure Timer: Controls the timing of exposure, placed within the primary circuit structure.
  • Step-Up Transformer: Changes electrical potential from volts to kilovolts, essential for proper X-ray function.