A transformer is used to do what?

A transformer is primarily used to raise or lower voltage levels in an electrical circuit. It operates on the principle of electromagnetic induction and consists of two coils of wire, known as the primary and secondary windings, which are wound around a magnetic core. When an alternating current flows through the primary winding, it creates a magnetic field that induces a voltage in the secondary winding. Depending on the number of turns in each winding, the transformer can either increase (step-up transformer) or decrease (step-down transformer) the voltage.

This ability to modify voltage levels is crucial in electrical power distribution. For instance, high voltages are used to transmit electricity over long distances to reduce energy losses, and transformers are employed at substations to lower the voltage to safer levels for residential or commercial use.

The other options do not accurately describe the primary function of a transformer. While some equipment does involve converting direct current to alternating current, that function is performed by inverters, not transformers. Transformers do not store electrical energy; that task is assigned to devices like capacitors or batteries. Additionally, transformers do not reduce electrical resistance; rather, they facilitate the safe and efficient transmission of electrical energy by adjusting voltage levels.