What does a transformer do in an electrical circuit?

The function of a transformer in an electrical circuit is to change the voltage level. Transformers operate based on the principle of electromagnetic induction, utilizing alternating current (AC) to transfer electrical energy between two or more coils of wire. By adjusting the number of windings in the primary and secondary coils, a transformer can either step up (increase) or step down (decrease) voltage levels while maintaining the power balance (minus losses) across its input and output.

This ability to adjust voltage levels is crucial for efficient power distribution. For instance, high voltages are used for long-distance transmission to minimize losses, and then transformers are employed at various points to reduce the voltage for safe use in homes and businesses.

The other options are related to different electrical concepts. Measuring resistance pertains to ohmmeters, converting AC to DC involves rectification, typically using diodes or rectifier circuits, and storing electrical energy is the function of capacitors or batteries, not transformers.