Electronics,semiconductors

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                                          ELECTRONICS


Definition of electronics:      electronics is a science which deals with the study of flow and control of electrons and the study of their behaviour and effects in vaccum,gases and semiconductors,and with devices using such electrons.



Actually everyone confuses between electronic and electrical.the basic difference between them is simple.

  • electronics deals with the flow of charge through non metal conductors
  • electrical deals with the flow of charge through metal conductors
 here non metal conductors means semi conductors.we will see how semi conductors act like non metals below.


metals can be classified as insulators ,semiconductors and conductors.
  1. INSULATORS:diamond
  2. SEMI CONDUCTORS: graphite, germanium and silicon
  3. CONDUCTORS: aluminium ,copper  











  • conduction band consists of holes which are positively charged
  • valence band consists of electrons which are negatively charged

BAND GAP:-

                               Band gap is the energy needed to promote an electron from lower energy level i.e valence band to higher energy level i.e conduction band.It is also known as energy gap (or) forbidden gap.


CONDUCTOR:-

                                   As shown in fig(c) there is no energy gap between conduction and valence band.so ,electrons can move freely resulting in flow of current.

INSULATOR:-

                                As shown in fig(a) the energy gap between conduction and valence band is 6ev .As energy gap is more electrons cant move from lower energy to higher energy level.that's why insulators  can't allow current to flow.

SEMI CONDUCTOR:-

                                        As shown in fig (b) the energy gap is 1ev. By applying a small amount of energy electrons can be moved to higher energy level.There results in flow of current.
  • current  in semiconductor results from the movement of both holes and electrons
  • they are doped with impurity atoms so that current is predominately due to either holes or electrons
  • DRIFT CURRENT is flow of charges under the influence of an electric field






Comments

  1. Jithendra10 June 2017 at 14:01

    A got very good knowledge is very to understand better than authorised text books

    ReplyDelete
    Replies
    1. Jithendra10 June 2017 at 14:03

      i got very good knowledge in this, is very easy to understand ur words good knowledge sharing

      Delete

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