BZT52C12S SMD 12V 200mW Zener Diode SOD-323

A Zener diode is a diode which allows current to flow in the forward direction in the same manner as an ideal diode, but also permits it to flow in the reverse direction when the voltage is above a certain value known as the breakdown voltage, "Zener knee voltage", "Zener voltage"

This is 12V voltage 200mW SMD SOD-323 Datasheet