Electricity, Conductors, Insulators, Semi-Conductors

Electricity

Atom is what builds this nature. We know it has neutron, proton and electron. These elements have some amount of energy, called ELECTRIC CHARGE(simply Charge)! Neutron has no charge associated with it, where as proton is said to be positive and electron negative.

The movement of these charged particles is Electric current. And physical phenomena related with these particles and current is Electricity.

Electric current

Current is established in a similar way where water in tank at higher level flows to lower level due to difference in energy. Similarly electrons move from higher energy state i.e. negative side to, lower energy state i.e. positive, constituting electron current. 

Direction of electric current is the way the positive charges move, so its opposite to electron current

SI Unit to measure charge is Coulomb, and Current is Ampere(A).

The charges which produce current must be free to move from one place to another. This is determined by the material which carries them, just like a water pipe, where the pipe shows how much water can flow and in what way.


These materials are known as Conductors, Insulators and Semi-Conductors. According to bandgap theory, the energy bands of these materials decide their type. And the property which defines how freely charges can move through them is called conductivity.

 Conductors

They are type of materials that allow electric charge to keep moving. This is possible only if atoms allow their electrons to move freely through its material. Conductors allow their outermost electrons to be free and make them float around. With proper guidance to these free electrons, through source called voltage (provides path from high state to low state), they constitute current in a very easy way.
 Like: Copper, Iron, Aluminum, and other metals.

Imagine a transparent glass, it has the ability to pass light, conductors are similar in case of charges.

Insulators

 These are materials that block charge movement. It means that they don not have free electrons for charge transfer from atom to atom. This causes current not to flow.
Like:Glass, Wood and other such materials.



This is more like a opaque object, which does not allow light to pass through, insulators are opaque to charge flow.

Semi-Conductors

Some have charges such that with proper energy source they provide free electrons for conduction. This provides a control over conductivity.
Like: Silicon, Germanium and other such materials.



They are more like translucent glass, they pass only required amount of light, same is semiconductors for charges.