A device used to convert AC power from one combination of voltage and current to another is called what?

A transformer is the correct answer because it is specifically designed to convert alternating current (AC) power from one voltage level to another through electromagnetic induction. It consists of coils of wire (windings) that create a magnetic field when AC flows through them. This magnetic field induces a voltage in a second coil of wire, allowing the transfer of electrical energy between the two coils at different voltage levels.

Transformers can either step up (increase) or step down (decrease) voltage depending on the turns ratio of the windings. This feature makes transformers vital in power distribution systems, where voltages often need to be adjusted for safe and efficient transmission over long distances.

In contrast, a rectifier is used to convert AC to direct current (DC), a capacitor stores electrical energy and can help in filtering or smoothing out voltage fluctuations, and an inductor stores energy in a magnetic field when current flows through it. Each of these devices serves a different function in electrical circuits and does not convert AC power between voltage and current combinations like a transformer does.