What is the primary application of a transformer in electrical systems?

The primary application of a transformer in electrical systems is to increase or decrease AC voltage levels. This functionality is critical in power distribution and transmission. Transformers operate on the principle of electromagnetic induction, allowing them to transfer electrical energy between two or more circuits through inductively coupled conductors—the transformer windings.

When a transformer is designed to step up voltage (increase voltage), it has more turns of wire in the secondary coil compared to the primary coil. Conversely, a step-down transformer has fewer turns in the secondary than the primary, resulting in a lower voltage output. This capability is essential for efficiently transmitting electricity over long distances, as high voltage levels reduce current and thus minimize energy loss due to resistance in the transmission lines.

While other options discuss functions that are vital in electrical systems, they do not pertain to the primary role of transformers. Storing electrical energy, converting DC to AC, and amplifying signals are accomplished by other devices such as capacitors, inverters, and amplifiers, respectively, which are not the primary function of a transformer. Therefore, understanding voltage transformation is crucial for anyone working with electrical systems.