Which device consists of four diodes and converts AC to DC?

• A. Rectifier
• B. Transformer
• C. Inverter
• D. Bridge rectifier

Answer: (D)

AC-to-DC conversion with diodes relies on steering current so it always flows in the same direction through the load. When four diodes are arranged in a bridge, two diodes conduct on the positive half of the cycle and the other two conduct on the negative half. This makes the current through the load flow in the same direction for both halves of the AC cycle, producing a pulsating DC output. The four-diode bridge rectifier is specifically designed to achieve full-wave rectification without needing a center-tapped transformer, which is why it’s the standard device described for converting AC to DC. The other devices serve different roles—transformers change voltage, and inverters convert DC to AC—so they don’t match the function described.