KBU4B-E4/51 Bridge Rectifier, 4A 100V, 4-Pin KBU. The Bridge Rectifier converts an Alternating Current (AC) input into a Direct Current (DC) output for full-wave rectification applications. The diode arrangement provides the same polarity of output for either polarity of input. A three-phase full-wave rectifier is an arrangement of six diodes in a bridge circuit configuration. The packages are designed for minimal size, highest reliability and maximum thermal performance.