Diode

Diode is component that work to allow electricity that flows to forward direction and block backward or opposite types of diode are  
    
Backward diode
      It is normally used specialized application only like very high speed switching
   
Baritt diode

This is a time diode and mostly used in microwave application .

Gunn diode

This is mainly used to generate microwave rf signals making it is less expensive to produce signals .this diode not have a pn junction

Laser diode
 
      It is not a normal diode and produce coherent light . this diode are normally used in DVD and CD driver and used as laser light pointer. this diode uses milliwatts to conserve power. But the life of diode is limited

Light emitting diode

         This diode produce visible light and  cheaper price. It is normally used in DVD player cl,computer switch,TV  and light bulb. Light emitting diode are normally known as LED. The new type of LED is OLED is organic light emitting diode.

Photo diode
    This diode is normally used to detecting light. It is normally used to counting and light breaking circuit

Schoottky diode
It is used in rf application and clamming diode

 Step recovery diode
             This diode is used generating radio frequency (Normally calls rf )and pulses.this diode cutt of or turn off in seconds

Zener diode
   It is normally used to produce stable electricity means the electricity is not change