The operation of many Electronics devices depended upon the movement of charged particles i.e.electrons with in them.Therefore, it is very necessary to study the structure and arrangement of atoms is solids.The objective of this chapter is to present elementary knowledge about the physical structure of solid.
This chapter also help to understand the energy bands with reference to conductors, insulators and semiconductors.Certain substance such as germanium,silicon,carbon etc.are neither good conductors like copper nor insulators like glass.In other words between the insulators and conductors there is another substance is called semiconductors.A semiconductor is a material whose conductivity lies somewhere that of a conductor and an insulator.Typical value of conductivity is 100 ohm's/cm3.Semiconductors are being extensively used in electronics circuits.Diodes,transistor and integrated circuits (IC) are also a semiconductor devices.Gallium arsenide is another semiconductors material becoming increasingly popular for microwave and solid state devices.
"The most important branch of physics which deals with the flow of electrons through a gas,vacuum or semiconductor is known is "ELECTRONICS"
Electronics essentially deals with the electronics devices or equipments which are used to production,propagation and reception of electromagnetic waves.such devices are being used in almost all the industries for increasing production,efficiency and quality control.
In the universe,everything have its existence,make up the matter.Matters exist in the three forms solid liquid gas.There are 109 elements divided in to several groups according to their chemical properties and atomic number.The smallest particle having independent existence and which cannot be further divided is known as an atom.