The 1SMAF4751A with Zener Diodes SMAF RoHS manufactured by Shikues is a type of bridge rectifier that is designed for use in DC power supplies. It consists of four components: two Zener diodes, two bipolar transistors, and a metal oxide varistor. The two Zener diodes provide protection against overvoltage and out-of-regulation conditions, while the two bipolar transistors act as switches that enable the four-terminal bridge rectifier to be triggered by an external signal. The metal oxide varistor (MOV) is used to protect the bridge rectifier from surge voltages. The 1SMAF4751A is RoHS-compliant, meaning that its construction and composition are free from the use of lead-based components.