What is the main function of a transformer?

The primary role of a transformer is to change the voltage level of an electrical supply. This is accomplished through electromagnetic induction, where alternating current in the primary coil generates a magnetic field that induces a voltage in the secondary coil. Depending on the turns ratio between the primary and secondary coils, a transformer can either step up (increase) or step down (decrease) the voltage. This voltage adjustment is crucial in power distribution systems, where high voltages are necessary for efficient long-distance transmission, and lower voltages are required for safe utilization by consumers. Thus, the correct choice highlights the transformer's essential purpose in managing voltage levels in electrical systems.