What is a transformer?

• A. A protective circuit breaker.
• B. A device that transfers electrical energy between circuits and changes voltage levels via electromagnetic induction.
• C. A device that stores charge.
• D. A conductor with resistance.

Answer: (B)

The main idea is that a transformer moves electrical energy from one circuit to another and changes the voltage using electromagnetic induction. It has two windings wrapped around a magnetic core; when AC current flows in the primary winding, it creates a changing magnetic flux that induces a voltage in the secondary winding. The voltage change is governed by the turns ratio, so the device can step voltage up or down while transferring power efficiently. It’s used to match voltages in the system and is a fundamental part of distribution and transmission. It’s not a storage device, not a resistor, and not a protective circuit breaker, which is why the correct description fits best.