Zener Diode is a special type of diode, which allows current to pass in the forward direction (from its anode to cathode) as well as in reverse direction (from its cathode to anode) after reaching Zener Voltage. This diode has a highly doped P-N junction. The difference between a normal diode and Zener diode is the voltage and sharpness of knee is well defined for a Zener diode but not for the normal diode. Zener diode can reliably work in breakdown region.This is a 1/2 Watt Zener Diode Voltage Regulator with tight limits and better operating characteristics that reflect the superior capabilities of silicon-oxide passivated junctions. All this is in an axial-lead, transfer-molded plastic package that offers protection in all common environmental conditions.