The following are the key differences between the PN junction and Zener diode.
- The semiconductor which conducts only in one direction is known as the PN-junction diode. And the Zener diode is the silicon diode which is optimized to operate in the breakdown region.
- The reverse current flow through the diode damage the PN-junction diodes. The reverse current flows through the diode when it is connected in reverse biased. The reverse biasing means the p-type material is connected to the negative terminal of the supply and the n-type material is connected to the positive terminal of the supply. But the Zener diode allows the current to pass through both the direction.
- The doping level of the PN-junction diode is low as compared to Zener diode. The width of the depletion region depends on their doping level. If the doping level of the diode is high, their depletion region is low and vice versa.
- The breakdown in PN-junction diode occurs at high voltage level, whereas in PN-junction diode it occurs at low voltage levels. The breakdown is the phenomenon of making the depletion region conductive. The heavily doped diode has a low depletion region.
- The PN-junction obey the ohm’s law whereas Zener diode does not obey the ohms law. The ohms law said that the voltage applies across the diode is equal to the product of the current and resistance applied across the diodes.
- The PN-junction diode is mainly used for rectification purpose, whereas the Zener diode is used for providing the constant voltage to the load whose voltage vary.
