Following are the difference between PN junction diode and zener diode:
| PN junction diode | Zener diode |
|---|---|
| PN junction is not properly doped to control reverse breakdown. | Zener diode is properly doped to control reverse breakdown. |
| PN junction has no sharp reverse breakdown. | Zener diode has small sharp reverse breakdown. |
| It conducts only in one direction. | It conducted in both the directions. |
| It is commonly used for rectification purpose. | It cannot be used for rectification, but commonly used for voltage regulation. |
| A PN junction diode will be permanently damaged for a large reverse current. | Zener diode will be not damaged for a large reverse current. |
| It burns immediately, if applied voltage exceeds the breakdown voltage. | It cannot be used for rectification, but commonly used for voltage regulation. |