Ch.6 X-ray Equipment RAD 145

Chapter 6: X-Ray Equipment

Power for X-Ray Generation

• Incoming Line Current

  • Electricity supplied to buildings

  • 60 Hz alternating current

  • rms 200-240 volts

  • X-ray equipment typically operates on 210-220V

• Single-Phase Power

  • Potential difference drops to zero with every change in current direction

• Three-Phase Power

  • Produced by generators

  • Commonly supplied by power companies

A Basic X-Ray Circuit

• Main X-Ray Circuit

  • Components: Exposure switch, Timer circuit

• Filament Circuit

The Exposure Switch

• Functions as a remote control switch to permit current flow

• Should be depressed to maximize tube life

• Mobile equipment typically requires a 6-foot cord

The Timer Circuit

• Electronic Timers

• mAs Timers

  • Monitor the product of mA and time on the secondary side of the high-voltage step-up transformer

• AEC Timers (Automatic Exposure Control)

  • Ensures consistency of radiographic quality

Generators

• Single-Phase

  • Full wave rectification results in 2 ripples of pulses

• Three-Phase

  • Full wave rectification results in 6 ripples of pulses

• High Frequency

  • Full wave rectification results in 12-13 ripples of pulses

• Capacitor Discharge Mobile Units

• Battery-Operated Mobile Units

  • Provide non-pulsating direct current

• Falling Load

  • Involves starting exposure with high amperage and allowing it to decrease during exposure

Circuit Components

• Main Switch

• Low Voltage or Primary Circuit

• High Voltage or Secondary Circuit

• Autotransformer (kVp selector)

• Exposure Switch

• Timer

• Kilovolt Meter

• Step-Up Transformer

• Variable Resistor (mA selector)

• Filament Ammeter

• Step-Down (Filament) Transformer

• X-Ray Tube

• Rectifiers