Question
Tue January 17, 2012 By: Vivek
 

what is a pn diode? how is it obtained?

Expert Reply
Wed January 18, 2012
when we join p type and n type semiconductors together, pn jn diode is formed. it allows  current to flow in forward bias(ie when p connected to positive and n connected to negative) and stops current through it in reverse bias.so it works like a valve. this pn diode is very useful for various useful operations.
here in this diode we can control current by varying the output voltage.
now p type semiconductor is obtained by adding impurity of pentavalent atom in the pure semiconductor(say si). so there we get enough free electrons which can flow if pd is applied.
n type semiconductor we get by adding impurity of trivalent atoms in pure semiconductors. so thetre will be defficiency of electrons called holes.which move when pd is applied.
Tue February 07, 2017

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