Page 103 - CITS - WCS - Mechanical

WORKSHOP SCIENCE - CITS

Most conductors are metals, such as copper, silver, and aluminum, due to their high electron mobility.
Conductors are used in a wide range of applications, including power transmission lines, electrical wiring, and
electronic components.
• Semiconductors are materials that exhibit intermediate electrical properties between conductors and insulators.
They possess unique characteristics that make them crucial for modern electronics. The conductivity of
semiconductors increases with temperature, as thermal energy generates additional charge carriers.
Semiconductors can be intentionally doped with impurities to control their conductivity and create either n-type
(electron-rich) or p-type (hole-rich) materials. Semiconductors are the foundation of modern electronics, used
in transistors, diodes, integrated circuits, and solar cells.Silicon and germanium are the most widely used
semiconductor materials

• Insulators are materials that oppose the flow of electric current, exhibiting high resistance and low conductivity.
The characteristics of insulators include. Insulators have tightly bound valence electrons, preventing the free
movement of electrons and hindering electric current flow. Most insulators are nonmetals or compounds, such
as plastics, ceramics, glass, and rubber. Insulators are used to prevent the flow of electric current, such as in
electrical insulation, circuit board substrates, and cable jackets.
In summary, conductors, semiconductors, and insulators are materials distinguished by their ability to conduct
electric current. Conductors allow easy current flow, semiconductors exhibit intermediate conductivity with
unique properties, and insulators hinder current flow. These classifications play a crucial role in the design and
function of electrical systems and electronic devices.
Classification of solids into three types,
Classification of solids into three types,
according to their band structure
according to their band structure
Insulators Semiconductor Conductor

Conduction Free
band electrons

Conduction
E =6 V Energy E =1 V band
e
g
gap
e
g
Valence Valence
band band
Holes

Insulator Semiconductor Metal

Sl. No. Conductors Semiconductors Insulators

Conductor easily A semiconductor An insulator does not
conducts the electrical conducts the electrics conduct any current

1 current current less than
conductor and greater
than insulator

Conductor has one Semiconductor has 4 Insulator has 8 valance
valance electron in its valance electrons in the electrons in the outer
outer most orbit outer most orbit most orbit
2

90

CITS : WCS - Mechanical - Exercise 9