A transformer is capable of changing which of the following?

Transformers are electrical devices specifically designed to change the voltage levels of alternating current (AC) while maintaining the power in the system. The key function of a transformer revolves around its ability to either step up (increase) or step down (decrease) voltage levels.

The principle of operation for transformers is based on electromagnetic induction, where the primary winding receives the input voltage and generates a magnetic field. This magnetic field induces a voltage in the secondary winding. Depending on the turns ratio of the windings, a transformer can either step up or step down the voltage.

When you look at the functionality offered by transformers, they can take in a high voltage input and reduce it to a lower voltage, or they can accept a low voltage input and transform it into a higher voltage output. This dual capability to convert voltages in both directions is essential for a wide range of applications in electrical systems, including power distribution.

Other options restrict this capability to either stepping down or stepping up alone, which does not accurately reflect the full function of transformers. Transformers are versatile components in electrical engineering, suited for multiple scenarios in voltage management.