Basic Work of diode

 
                  

• A diode is a 2 lead semiconductor that acts as a one way gate to electron flow.  
• Diode allows current to pass in only one direction. 
• A pn-junction diode is formed by joining together n-type and p-type silicon.
• In practice, as the n-type Si crystal is being grown, the process is abruptly altered to grow p-type Si crystal. Finally, a glass or plastic coating is placed around the joined crystal.
• The p-side is called anode and the p-side is called cathode. When the anode and cathode of a pn-junction diode are connected to external voltage such that the potential at anode is higher than the potential at cathode, the diode is said to be forward biased. 
• In a forward-biased diode current is allowed to flow through the device. 
• When potential at anode is smaller than the potential at cathode, the diode is said to be reverse biased. In a reverse-biased diode current is blocked.