P-N junction diode

without knowing the concepts of diode operation we can't get into the concepts of electronics in depth.so try to know the details  about a diode.

Basic diode operation

by viewing the above link you may know the details of basic diode operation.

After that when we connected a source to it in different modes of operation then how the diode will behave we will see in below link..

https://www.youtube.com/watch?v=syUoJ3-nCRo