What is the principle of a p-n junction diode ?

The resistance of a p-n junction becomes low when forward biased and becomes high when reversed biased.

When the P-N junction is forward biased, the built-in electric field at the P-N junction and the applied electric field are in opposite directions. When both the electric fields add up, the resultant electric field has a magnitude lesser than the built-in electric field. This results in a less resistive and thinner depletion region.

When the P-N junction is reverse biased, the built-in electric field and the applied electric field are in the same direction. When the two fields are added, the resultant electric field is in the same direction as the built-in electric field, creating a more resistive, thicker depletion region.

• The resistance of a p-n junction becomes high when forward biased and becomes low when reversed biased. FALSE
• The current in reverse bias is due to drift current of minority carriers. TRUE but not the principle of p-n junction.
• The current in reverse bias is due to diffusion current of majority carriers. FALSE