Some Definition related EEE

Free electron:

1.     (Physics / General Physics) any electron that is not attached to an ion, atom, or molecule and is free to move under the influence of an applied electric or magnetic field.

2.     electron that is not attached to an atom or ion or molecule but is
free to move under the influence of an electric field.

Current: Electrical current is a measure of the amount of electrical charge transferred per unit time. It represents the flow of electrons through a conductive material.

Current is a scalar quantity (though in circuit analysis, the direction of current is relevant). The SI unit of electrical current is the ampere, defined as 1 coulomb/second.

Voltage: Voltage is a representation of the electric potential energy per unit charge. If a unit of electrical charge were placed in a location, the voltage indicates the potential energy of it at that point. In other words, it is a measurement of the energy contained within an electric field, or an electric circuit, at a given point.

Voltage is a scalar quantity. The SI unit of voltage is the volt, such that 1 volt = 1 joule/coulomb.

Voltmeter: A voltmeter is an instrument used for measuring the electrical potential difference between two points in an electric circuit.

OR, Voltmeter is an instrument for measuring potential difference in volts.

AC & DC Current: In alternating current (AC, also ac) the movement (or flow) of electric charge periodically reverses direction. In direct current (DC), the movement (or flow) of electric charge is only in one direction.

The difference between Conductor, Semi-conductor & Insulator:

Conductor	Semi-conductor	Insulator
i) In case of conductor, conduction band and valence band are overlapping, and therefore electrons are very free to move.	i) In Semiconductors there is a bit distance between the valence band and conduction band. When there are heated electron jump to the conduction band from the valence band.	i) In case of Insulators there is a big distance between the conduction band and valence band. so electron can not move from valence band to the conduction band.
ii) Conductors are liable to conduct electricity.	ii) The semiconductors are intermediate.	ii) Insulator do not allow electricity pass through them.

The difference between Conductor and Insulator: The Difference between conductors and insulators is that conductors conduct electricity and insulators do not. On the basis of energy band theory conductors have partially filled valence band and insulators has fully filled valence band.

Conductor	Insulator
i) The substances through which electricity can pass are known as conductors.	i) The substances through which electricity cannot pass are known as insulators.
ii) There are many free electrons and ions in the conductor, so they conduct electricity.	ii) There are no free electrons and ions present in the insulator, so they do not conduct electricity.
iii) According to energy band theory in conductors the valence band and conductor band are overlapped, so electrons from valence shell easily jump to conductance shell. In this way conductors conduct electricity.	iii) In insulators there is a large forbidden band present between valence band and conduction band, so insulators do not conduct electricity.

Thanks for being with us. Keep visiting for more updates. :)