Wednesday, 7 October 2020

Solid State Electronics

 




Solid State Electronics, electronic gadgets don't rely solely on natural conductors and insulators.

 

In the late forties of the last century, solid-state devices were invented, which performed the function of vacuum tubes. These tools were made from materials known as (semiconductors) such as silicon and germanium. These tools enlarge and control electrical signals.

 

Semiconductor properties

  • very small.
  • It does not generate much heat.
  • They cost little to manufacture.
  • Its life span reaches 20 years.

 

Belt theory of solids

Solid State Electronics It is a description of the electrical conductivity of a material by describing the valence and conduction beams separated by forbidden gaps.

 

Power packs

  1. Electrical conductivity can be described as follows:
  2. Energy beams with lower energy levels or valence beams are filled with electrons bound in the crystal.
  3. In higher energy levels, or as bundles of conduction, electrons can move from one atom to another.
  4. The valence and conduction beams are separated by a gap in which the electron is forbidden to be present, and therefore it is called the banned or blocked energy regions.

 

Example

At a temperature of zero kelvin, the valence beam of silicon is completely filled with electrons and the conduction beam is completely empty.

• When the temperature increases, more valence electrons gain enough energy to jump from the gap to reach the conduction beam, and the conductivity of silicon increases.

 

 Insulators

The valence beam in the insulating material is filled, while the connecting bundle is empty.

• He must acquire an electron

A large amount of energy to transfer to the conduction beam.

Because there are energy gaps in insulators of (5 eV) and this energy is not possessed by electrons and therefore cannot jump from the forbidden gap. Therefore, the insulating material does not conduct electric current.

 

Semiconductors

Silicon and germanium are the most important semiconductors used in electronic devices.

• It has four valence electrons and semiconductor atoms in the crystal linked by covalent bonds.

 

Electrons and gaps

• If the electron is released (moved from the valence beam to the conduction beam), then its place remains a gap.

It is an empty energy level in the valence beam and the total charge of the atom becomes positive with the increase in the amount of the cavities.

 

Treated semiconductors

  • The conductivity of a pure semiconductor has to be increased by a large amount in order to make practical tools.
  • Therefore, electron donor or acceptor atoms are added in small concentration to pure semiconductors called impurities.
  • It increases its conductivity by providing additional electrons or gaps.
  • Semiconductors that are treated by adding impurities are called (treated) impure semiconductors.

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