| LED | PN junction diode |
|---|---|
| The LED emits light. | The PN junction diode cannot emit light. |
| The LED uses GaAs, GaAsP or GaP material. | The PN junction diode silicon or germanium material. |
| In LED all energy converted into a light | In PN junction diode all energy converted into a heat. |
| It’s on state voltage ranges between 1.2 V to 2.0 V. | Its on-state voltage drop is 0.7 V for silicon diode and 0.3 V for germanium diode. |
| It has very low value of reverse breakdown voltage. | It has high value of reverse breakdown voltage. |
| It is used as a light source in fiber optics, as an indicator in 7 segment displays etc. | It is used in rectifiers, clippers, clamping, voltage multipliers etc. |