Which term describes the device that converts AC to DC?

• A. Rectifier
• B. Inverter
• C. Transformer
• D. Generator

Answer: (A)

The main idea is turning alternating current into direct current. A rectifier is the device designed for this task: it uses diodes (or controlled switches) to block the negative half-cycles of AC, allowing current to flow in only one direction, which creates direct current (often a pulsating DC that can be filtered for a steadier output). This makes rectifiers essential in power adapters, battery chargers, and most digital electronics power supplies.

Inverters do the opposite—they convert DC to AC. Transformers work only with AC to change voltage levels and do not convert AC to DC. Generators produce electrical power from mechanical energy, and while their output can be AC or DC depending on design, they aren’t the device that converts existing AC into DC; that job is handled by a rectifier if DC output is needed.