What is the primary function of a transformer in an electrical circuit?

The primary function of a transformer in an electrical circuit is to change voltage levels. Transformers operate on the principle of electromagnetic induction to transfer electrical energy between two or more circuits through inductively coupled conductors. This allows them to either step up (increase) or step down (decrease) voltage levels, depending on the turns ratio of the windings.

Transformers are essential in electrical systems because they ensure that the voltage is appropriate for the load being supplied, optimizing performance and safety. They help in transmitting electrical power over long distances by increasing the voltage to reduce losses during transmission, and then lowering the voltage for usage at the point of consumption.

The other options do not accurately represent the primary function of a transformer. For instance, while transformers can be used to increase voltage, stating that their sole purpose is to increase voltage overlooks their capability to also decrease it. Converting alternating current to direct current is a function of rectifiers, not transformers. Storing electrical energy is a function of devices like batteries and capacitors, rather than transformers.