PART - 1
Diode look like –
And the symbols of diode
are –
CONDUCTORS –
All Metals. Like - Silver,
Gold. Cupper, Steel, Iron etc. Here we see the conduction band (C.B) and the valence
band (V.B) is over lapping each other. For that reason, the electrons are easily
move from V.B to C.B.
INSULATORS-
Rubber,
Glass, Diamond, Wood, Plastic, Dry Paper etc. are the insulators, which can not
carry the electron from V.B to C.V. Because the distance between V.B and C.V is
grater then 5 electro volt (ev). This gap is called energy gap (Eg).
SEMI-CONDUCTORS-
Germanium
and Silicon are the semi-conductors, because the Eg V.B and C.V is less then 5ev.
So we can get the flow of electrons to applying some heat energy. Like-
In
0k temp.-
Ge = 0.78ev
Si = 1.21ev
In
300k temp.-
Ge = 0.72ev
Si = 1.1ev
Those types of semi-conductors are called in-centric semi-conductor.
If
we add some impurities with those in-centric semi-conductor to increase the
speed of the flow of electrons then those elements are called ex-centric semi-conductor.
The
process to create the ex-centric semi-conductor is called Doping.
