The function of the autotransformer is to.. Stabilize the fixed voltage of the step-down transformer

The function of the autotransformer is to:

• a- Stabilize the fixed voltage of the step-down transformer.***
• b- Act as a voltage regulator to the filament.
• c- Select the primary voltage for x-ray machine circuits.
• d- Help reduce power loss in the transformer due to eddy currents.

While autotransformers can play a role in voltage stabilization, that's not their primary function. Here's a more accurate explanation of their key functions:

Primary Functions of Autotransformers:

- Voltage Transformation:

• They can step up or step down voltage levels, similar to conventional transformers.
• They are often used to adjust voltage levels in power transmission and distribution systems, as well as in various industrial and commercial applications.

- Voltage Regulation:

• They can help maintain a relatively constant output voltage despite fluctuations in input voltage or load.
• This is achieved by adjusting the tap connections on the winding, which changes the turns ratio and effectively regulates the output voltage.

- Starting Motors:

• They are frequently used to reduce starting current in large electric motors.
• By applying a reduced voltage during startup, they minimize the inrush current that can strain electrical systems.

- Impedance Matching:

• They can match the impedance of different electrical components, ensuring efficient power transfer and reducing potential for overheating or damage.

- Phase Shifting:

• In some applications, they can create a phase shift between input and output voltages.
• This is useful for certain types of power control and measurement systems.

Key Advantages of Autotransformers:

- Smaller and Lighter:

For the same voltage ratio, they are often more compact and lighter than two-winding transformers due to their single winding design.

- More Efficient:

They typically have higher efficiency, especially for small voltage transformations, as they have lower internal losses.

- Cost-Effective:

They often cost less to manufacture than two-winding transformers, making them an economical option in many applications.

Important Considerations:

- Lack of Isolation:

Autotransformers do not provide electrical isolation between the primary and secondary circuits. This must be considered in safety-critical applications where isolation is required.

- Short Circuit Protection:

They may require additional protection devices to prevent damage in case of short circuits.