Classification of materials based upon resistance

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Classification of materials based upon the resistance:-

1.       Conductors:
-          Materials which offer least resistance to flow of electrons through them.
-          Example: Silver,Copper,Aluminium
-          Resistivity range: 10^(-8)to 10^(-3)
-          Applications: Cables core etc.
-          Note1: Resistance of a conductors increases with the increase in temperature.
-          Note2: Human body and earth acts as conductors.



2.       Insulators:
-          Materials which offer very high resistance to flow of electrons through them.
-          Examples: Mica,Glass,Porcelain
-          Resistivity range: 10^(6)to 10^(18)
-          Applications: Insulation of cables etc.
-          Note: Resistance of insulators decreases with the increase in temperature.



3.       Semi conductors:
-          Materials which acts as conductors sometime and insulators sometime.
-          Examples: Germanium, silicon
-          Resistivity range: 10^(-3) to 10^(6)
-          Applications:  Diodes, Printed circuit boards etc.
-          Note: Resistance of semiconductors decreases with the increase in doping.



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