Re: What is the importance of pn junction in moderen electronics?

Hi,
The PN junction diode is the basic unit of nearly all the electronic goods 
you see today. It basically consists of a silicon wafer (a very thin slice 
or lamina of silicon) on which different atoms of elements are introduced 
(the process is known as doping) . The elements create diferently charged 
regions. One side has excess of electrons, while the other side has a lack 
of them.
This serves as a device which allows current only to pass in one direction.
This simple device (the PN junction diode) led to the development of 
Transistors and later to many other complex devices such as logic gates, 
chipsets etc. All the current personal computers too use this simple PN 
junction as their basic building block.

Examples of efficient products include:
Radio sets, Televisions, audio systems, microprocessors, telephone and 
communication equipment etc. The list is endless!! Basically most of the 
chips you see around you use the PN junction diode.

If you need further clarification feel free to email me,
Nauzad