Ohm's law

Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points.

V = IR

Resistance (R) is the Proportional constant.

In circuit analysis, three equivalent expressions of Ohm's law are used interchangeably:

V = IR ;      I = V/R ;      R = V/I

Resistor, Capacitor & Inductor

There are three basic elements in electronic circuits they are Resistor, Capacitor and Inductor this are called passive elements.

 

Resistor (R)

Resistor represents amount of resistance in given circuit. Resistance is the measure of opposition to electric current.

Units of resistance is ohms.

Ohm is named after German physicist George Ohm(Ω).

Capacitor (C)

The electric component that stores the electric charge is called capacitor. Capacitor's ability to store charge is called capacitance which is measured in 'Farads' (F).

Farad is named after English physicist Michael Faraday.

 

 

Inductor (L)

And inductor presents amount of inductance in a circuit. The inductance is the ability of a component to generate electromotive force due to change in flow of current.

Inductance is measured in Henrys(H).

Henry is named after American scientist Joseph Henry.

Inductor strores the energy in the form of magnetic field.

Active components & Passive components

Active components

Active components supplies energy to the circuit. Active components can control the electron flow.

Examples:

            Voltage Sources

            Current Sources

            Generators

            Diodes

Passive components

Passive components receive the energy, which it can either dissipate, absorb or store it in the electric field or magnetic field.

Examples:

            Resistor

            Capacitor

            Indctors

Structure of Atom

The atoms have a planetary type of structure according to the classical Bohr model.

All the protons and neutrons are bound together at the centre of an atom. Which is called nucleus. while all the electrons were moving around the nucleus.

In an atom the number of protons and the number of electrons are equal. The number of protons is called atomic number. Total number of protons and neutrons in the nucleus is called atomic weight.

Electrons revolving around the nucleus do not more in the same orbit(Shell). Each shell contains fixed number of electrons. A shell can contain maximum of 2n² electrons.

Electrons closer to the nucleus has high force of attraction and electrons farther from the nucleus has less force of attraction. Show the electrons in the outer shell has loosely bonded to the nucleus.

the amount of energy required to extract the valence electrons from outer shell is very less.

When an atom absorbs energy from external source, its energy levels increases and electron moves to the next orbit. If such external energy is observed by valence electron, it tries to move to next orbit but there is no next orbit so it is completely removed from the force of attraction of nucleus.

Structure of Matter

According to the modern electron theory, matter is composed of three fundamental particles. these are neutron proton and electron.

Proton is positively charged.

Electron is negatively charged.

Neutron is uncharged.

The mass of neutron and proton is same.

Fundamental Element	Nature of Charge	Mass in Kg
Neutron	No Charge	1.675 x 10-27
Proton	Positive	1.672 x 10-27
Electron	Negative	9.107 x 10-31

 

There is no difference between an electron of copper and an electron of aluminium or an electron of any other element. similarly the neutrons and protons of various atoms or characteristic wise identical in nature.