Diodes have several basic applications including half-wave rectification, full-wave rectification, and voltage regulation. A half-wave rectifier uses a diode to allow current to flow through it in only one direction, converting an alternating current into a pulsing direct current. A full-wave rectifier uses a bridge rectifier configuration to allow current to flow through on both halves of the alternating current cycle. Voltage regulators, which can use Zener diodes or integrated circuits, automatically maintain a constant voltage level.