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

The primary purpose of a transformer in electrical systems is to change the voltage levels of electrical energy. Transformers operate on the principle of electromagnetic induction, allowing the transfer of electrical energy between circuits while increasing or decreasing the voltage as required for efficient transmission or suitable usage. This ability to adjust voltage levels is crucial for minimizing energy loss over long distances in power transmission and for ensuring that electrical devices receive the correct voltage for their operation.

Transformers can either step up (increase) or step down (decrease) voltage, depending on the turns ratio between the primary and secondary coils. This capability is essential in various applications, from utility power lines to residential distribution systems.

The other options do not align with the fundamental functions of a transformer. Detecting voltage surges pertains more to protective devices rather than a transformer's role. Converting AC to DC current is a function of rectifiers, not transformers, as transformers do not change the type of current. Protecting appliances from overload typically involves circuit breakers or fuses, which are designed to interrupt power in case of excessive current flow but do not change voltage levels.