In which portion of the x-ray circuit is the step-down transformer located?

In which portion of the x-ray circuit is the step-down transformer located?

• A. High voltage circuit
• B. Filament circuit
• C. Grid circuit
• D. Anode circuit

Answer: (B)

The filament circuit is where a step-down transformer is used. Heating the x-ray tube filament requires a low voltage but high current to cause thermionic emission. A step-down transformer lowers the incoming mains voltage to a few volts while allowing plenty of current to flow through the filament. This contrasts with the high-voltage circuit, which needs a high voltage to accelerate electrons and uses a step-up arrangement, and with the grid/anode aspects, which involve control and high-voltage delivery rather than filament heating. So the step-down transformer sits in the filament circuit.

The filament circuit is where a step-down transformer is used. Heating the x-ray tube filament requires a low voltage but high current to cause thermionic emission. A step-down transformer lowers the incoming mains voltage to a few volts while allowing plenty of current to flow through the filament. This contrasts with the high-voltage circuit, which needs a high voltage to accelerate electrons and uses a step-up arrangement, and with the grid/anode aspects, which involve control and high-voltage delivery rather than filament heating. So the step-down transformer sits in the filament circuit.