What is the main purpose of a transformer in electrical theory?

The main purpose of a transformer in electrical theory is to step up or step down voltage levels. Transformers operate on the principle of electromagnetic induction and are designed to transfer electrical energy between two or more circuits through inductively coupled conductors, typically called windings.

When alternating current (AC) flows through the primary winding, it creates a changing magnetic field that induces a voltage in the secondary winding based on the turns ratio of the windings. This allows transformers to increase (step up) or decrease (step down) voltage levels while maintaining the same frequency. The voltage can be adjusted to suit the requirements of various electrical systems, making transformers essential for efficient power distribution and usage across different voltage levels in electrical grids and devices.

This functionality is crucial, especially in power transmission, where high voltages are often used to minimize losses over long distances, followed by local step-down transformers that provide lower voltages suitable for consumer use.