What is the purpose of the step-down transformer in the x-ray circuit?

The purpose of the step-down transformer in the x-ray circuit is to lower the voltage prior to exposure. In the x-ray machine, there are two main transformers: the step-up transformer, which increases the voltage to accelerate electrons toward the target anode, and the step-down transformer, which reduces the voltage for the filament circuit.

The step-down transformer is critical because it ensures that the filament of the x-ray tube operates at the lower voltage necessary for heating. This heating is essential for thermionic emission, where electrons are released from the filament. Those electrons, once heated, are then directed toward the anode at high voltage (achieved by the step-up transformer) to produce x-rays.

Thus, the step-down transformer's role is foundational for properly managing the voltage levels required for different functions in the x-ray circuit, specifically in preparing the filament to produce the electrons needed for x-ray generation.