Explain how a p-n junction makes an excellent rectifier.

A p-n junction, formed by connecting p-type and n-type semiconductors, creates a potential barrier across the junction that behaves differently under forward and reverse bias conditions. These distinct behaviors make it an excellent rectifier. In the forward-biased condition, the potential barrier decreases, allowing charge carriers to flow through the junction, facilitating current flow. Conversely, in the reverse-biased condition, the potential barrier increases, preventing charge carriers from flowing across the junction, effectively blocking current flow. As input voltage alternates between positive and negative half-cycles, the p-n junction conducts during the positive half-cycle and blocks the reverse current during the negative half-cycle, converting AC input into pulsed DC output. This unidirectional flow of current makes the p-n junction an effective rectifying component in electrical circuits.