An electrical transformer is a device that changes the voltage of electricity in a circuit. It works on the principle of electromagnetic induction, allowing it to either increase (step-up) or decrease (step-down) voltage levels. This is essential for efficiently transmitting electricity over long distances, as higher voltages reduce energy loss. Transformers consist of two coils of wire, known as the primary and secondary windings, wrapped around a core made of magnetic material. When alternating current flows through the primary winding, it creates a magnetic field that induces a voltage in the secondary winding, enabling the transfer of electrical energy between the two circuits.