A __________ is an electrical device that converts AC electricity from one voltage level to another.

• A. Rectifier
• B. Capacitor
• C. Transformer
• D. Inductor

Answer: (C)

Converting AC voltage levels is the job of a transformer. It works by electromagnetic induction between two windings wrapped around a magnetic core. When alternating current flows in the primary winding, it creates a changing magnetic flux that induces a voltage in the secondary winding. The voltages relate by the turns ratio, so you can step the voltage up or down as needed. Because it relies on AC to produce the changing flux, a transformer won’t work with DC. In contrast, a rectifier changes AC to DC, a capacitor stores and smooths voltage, and an inductor stores energy and filters but does not by itself change the AC voltage level between source and load.