What does a transformer do to alternating current?

A transformer primarily functions to change the voltage of alternating current (AC) to another level, which is crucial for the transmission of electricity over long distances. By stepping up (increasing) or stepping down (decreasing) the voltage, transformers enable efficient power distribution from power plants to homes and businesses.

When the voltage is increased, the current decreases, which helps minimize energy loss due to heat during transmission. In contrast, when the voltage is lowered, it is suitable for safe use in electrical systems at homes or industries. This ability to modify voltage levels without changing the frequency of the AC makes transformers vital components in electrical engineering and power management.

Other options, while relating to electrical concepts, do not accurately describe a transformer's role. For instance, transformers do not store energy; their purpose is to facilitate the transfer of AC electrical energy at different voltage levels. They also do not convert AC to direct current; that process is managed by rectifiers. Additionally, a transformer does not primarily increase the current flow but rather alters voltage while adhering to the power conservation principles.