What is the purpose of a transformer?

The purpose of a transformer is to change the voltage of alternating current in a circuit. Transformers operate on the principle of electromagnetic induction, which allows them to either increase (step-up) or decrease (step-down) the voltage levels of AC electricity while maintaining the same power level (minus losses due to heat and other factors). They are essential components in power distribution systems, enabling efficient transmission of electrical energy over long distances by stepping up the voltage, which reduces energy losses in the form of heat, and then stepping it down again for safe use in homes and businesses.

The other options focus on functions that are not applicable to transformers: converting sound waves into electrical energy concerns transducers, measuring electrical resistance pertains to multimeters or ohmmeters, and providing backup power relates to batteries or uninterruptible power supplies (UPS). Understanding the specific role of a transformer helps clarify its critical function in electrical engineering and power management.