Core Circuit Components
The x-ray machine consists of three main circuit sections:
1. Console circuit
2. High-voltage circuit
3. X-ray tube circuit
A circuit breaker protects the entire system by shutting off power during overloads or
short circuits.
A line voltage compensator monitors incoming line voltage and adjusts the
autotransformer to correct fluctuations.
Major and minor kVp controls adjust the autotransformer setting.
Transformers & Rectification
The high-voltage transformer is a step-up transformer with a turns ratio of 500:1 to
1000:1.
Voltage increase is indicated by increased wave amplitude.
Single-phase systems require at least four diode rectifiers.
Modern diodes are made from N-type and P-type silicon crystals.
A potential barrier forms at the p-n junction allowing current flow.
When current reverses, the diode becomes polarized, blocking flow.
Rectification must be the final step before electricity enters the x-ray tube.
X-Ray Tube & Filament Circuit
Thermionic emission releases electrons from the heated filament.
Filament heating requires high amperage current.
Filament current flows when the rotor button is pressed.
A delay is required to allow the filament to heat.
Excessive rotoring causes filament wear and tear.
Filament step-down transformer ratio is typically 1:44.
Filament current does not require rectification.
mA selection routes current through specific electronic resistors.
Electrical Measurement
A meter placed in series measures amperage.
A voltmeter is connected in parallel to compare electrical potential.
A pre-reading voltmeter prevents high-voltage exposure at the console.
The mA meter measures current flowing across the x-ray tube.
Tube current is only a fraction of filament current.