what is conductor,insulator and semiconductor??

conductor :

conducting materials are good conductors of electricity and are characterized by a larger electrical conductivity and small electrical resistivity.

• silver.
• copper.
• aluminium etc.

  

  copper wire

 Insulator:

Insulating materials are characterized by poor electrical conductivity  and are used to block current from flowing where it is not to pass. 

• glass.
• rubber.
• wood.
• quartz etc...

  

  picture of glass

semiconductor:

there is another group of materials which are neither good conductors nor good insulators. at room temperature such materials have conductivites considerably lower than those of conductor and much higher than those insulators.such  materials are called semiconductor. below the example of a semiconductor(c,si,pb,sn,Ge) you want to know about active and passive component click here  active and passive components

• carbon(C)
• silicon(Si)
• Lead(Pb)
• Tin(Sn)
• Germanium(Ge)

• 

  diode made in si and Ge