What is the purpose of a transformer in electrical systems?

The purpose of a transformer in electrical systems is primarily to change the voltage levels in alternating current (AC) circuits. Transformers operate on the principle of electromagnetic induction and are used to either step up (increase) or step down (decrease) voltage levels while maintaining the same frequency. This ability is crucial for efficiently transmitting electricity over long distances, as higher voltages reduce energy losses due to resistance in the wires.

For example, electricity is often generated at a certain voltage and then stepped up by a transformer for transmission over power lines. Once it reaches its destination, another transformer steps the voltage down to a usable level for homes and businesses. This process ensures that electrical systems operate efficiently and safely at the required voltage levels.

The other choices do not correctly capture the primary function of a transformer. While converting AC to DC is part of what rectifiers do, it is not the job of a transformer. Storing electrical energy is typically associated with batteries or capacitors, not transformers. Measuring electrical consumption is done with devices like ammeters and watt-hour meters, which measure current and energy use, rather than involving voltage transformation.