# Electrical Engineering Basics And Formulas

The basic things of Electrical engineering is called fundamentals(electrical components).

• Electric charges.
• Electric current and voltage.
• Electrical circuit Elements.
• Fundametal laws electric engineering.

Electric charges

Electrical Charges is the physical property of the matter,The main cause is due to force experience
by the two closed electical charged particles.

Coulomb’s law
The force exerted by one charge q on another charge Q is givern by colomb’s law.

coulmb’s law F= (kqQ/r^2)
Whrere, constant k=8.99*10^9Nm^2/c^2.
r-> is the distance between two charges.

SI UNIT OF CHARGE : Coulomb (C)

Material are divided into three according to the how easily charge( ie electons) to flow along them.

Conductors – (eg: Metals)
Semi-condutors – (eg: Silicon)
Insulators – (eg: Rubber,wood,platic)

Electric Current and Voltage

The rate flow of charges in a condutor is called current.The electric current i is givern by,

Current (i) =Q/t
where Q charge in coulomb and t charge flowing time in seconds.

SI UNIT OF CURRENT : Ampere (A)

“The flow of one coulomb of charge in one second is one unit electric current.”

a) Direct Current(DC): The flow charges is in always in one direction and steady for the period of
contstant time is known as Dc.
b) Alternating Current(AC):Name indicates likes its alternating.The flow of charges first in one direction
then the other direction repeating this cycle in definite freequency is known as AC.

Voltage

current flow through electrical element when a voltage appears acroos the terminals of the element
just like whater flows through a pipe when pressure differnce appears acroos the pipe.

SI UNIT OF VOLTAGE : Volt(V)

Electic Power and Energy

The work done or energy transferred in an electric circuit wih a voltage V is givern VQ Where Q is the charge moved through the circuit in a given time t . hence power

Power (p) = Vq/t or V*(q/t) P= VI
Where I is current

SI UNIT OF POWER : Watt(W)

Energy

cappacity to doing work is called Energy.

Energy (E) = VIT

SI UNIT OF ENERGY : Joule(J)

Electrical circuit Element

Componnents of electric circuit are called circuit elements.The circuit element may be active and passive elements. There are Three types of passive elements ressistors,capacitorand inductor.

Resistor

The oppostion of to the passage of an electric current through the conductor.It is the property is most
commonly described by Ohme’s law states that “the voltage acorss the resistor is dirctly proportional to
the cuurent at constant temperature and pressure”
.

Resistance (R) = V/I

SI UNIT OF RESISTANCE : ohm

series conection : Rs=R1+R2+…..
parallel connection: Rp=1/R1+1/R2……

Capacitor

Capacitor is charge storing device.Capacitor allso called condenser.It an electric device consisting of two
conductors sepearted by an insulating dielectric medium.The raio of on one of the condutors of the capacitor to the potential differnce between two condutor is called capacitance

Capacitance (C) = Q/V

SI UNIT OF CAPACITANCE : Fard

Inductor

Its allso a charge storing device .It stores maganetic energy.

Inductance (I) = L*(di/dt)
Where L self inductance

SI UNIT OF INDUCTANCE : Henry

Reference

Tony

Hi, Myself Tony George. An Electrical Engineer by Education, a Software Developer by Profession and an Education Blogger by Passion. In the past, I had been working as an Engineer in KSEB. The knowledge that I have acquired I would like to share here with you. I will be happy if these articles can give you a way to your career growth. Feel free to contact me.

### 7 Responses

1. Kolin says:

Hai tony nice work ,Provide some more laws and explanation…

• Tony kuttan says:

Thanks Kolin, I will

• REMYA says:

informative and helpful notes Tony,, thanks

2. KarSho says:

Good One…

3. Rajeev says:

Good work!

4. lekshmi says:

Hi
I wnt to know is this was the last chance for ECE candidates to apply for this post give reply early as possible

5. Manasa says:

Good going Tony..all the best for the upcomings..