A rectifier diode is a semiconductor device that allows current to flow in one direction while blocking it in the opposite direction. This property makes it essential for converting alternating current (AC) to direct current (DC), which is necessary for powering electronic devices. Rectifier diodes are commonly used in power supplies and various electronic circuits. These diodes are typically made from materials like silicon and are characterized by their ability to handle high voltage and current levels. They come in different types, such as standard rectifier diodes and Schottky diodes, each suited for specific applications based on their performance and efficiency.