In the following sections, we will introduce the basic concepts of
semiconductor physics and discuss some semiconductor devices like
junction diodes (a 2-electrode device) and bipolar junction transistor (a
3-electrode device) A few circuits illustrating their applications will also
be described 14 2 CLASSIFICATION OF METALS, CONDUCTORS AND
SEMICONDUCTORS
On the basis of conductivity
On the basis of the relative values of electrical conductivity (s ) or resistivity
(r = 1/s ), the solids are broadly classified as:
(i) Metals: They possess very low resistivity (or high conductivity)