SOLUTION

A PN-junction diode is formed when a p-type semiconductor is fused to an n-type semiconductor creating a potential barrier voltage across the diode junction

Forward Biasing: If the positive terminal of an external battery is connected to p-type and its negative terminal to n-type of PN junction then such a biasing is called forward biasing. Forward biasing reduces potential barriers and hence, depletion layer width decreases. The current is due to majority carries. Current is quite large when applied, with forward voltage. In forward biasing condition, the PN junction acts as a Closed switch.

• An ideal diode acts as a short circuit under forward bias condition. A practical diode offers small but finite resistance under forward bias condition.
• An ideal diode acts as an open circuit under reverse bias condition. A practical diode offers large but not infinite resistance under reverse bias conditions.
• A diode conducts current when forward biased and blocks current when reverse biased. This property of the diode is made use of in rectifier circuits.