A device that converts AC voltage levels and is commonly used to step up or step down voltages is called a __________.

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

Answer: (C)

Voltage level transformation in AC systems is achieved with a transformer. A transformer has primary and secondary windings wrapped around a magnetic core. When alternating current flows in the primary, it creates a changing magnetic field that links to the secondary winding. That changing flux induces a voltage in the secondary, and the output voltage is determined by the turns ratio—the number of turns on the secondary compared with the primary. If the secondary has more turns than the primary, the voltage goes up (step-up); if it has fewer turns, the voltage goes down (step-down). Transformers require AC because the changing magnetic field is essential for induction; a steady DC would not sustain the transfer and could saturate the core. This makes transformers the go-to device for changing AC voltage levels in power systems. The other devices have different roles: a rectifier converts AC to DC, a capacitor stores electrical energy, and an inductor stores energy while influencing current, but neither primarily changes voltage levels between circuits like a transformer does.