1. Basic Electronics PART 1

Basic Electronics PART 1

Potential :

In classical electromagnetism the electric potential at a point is equal to the electric potential energy ( measured in jouls ) of a  charged particle at a location divided by the charge ( measured in coloumbs ) of that particle. it is measured in Volts.

Potential Difference :

The Potential Difference is measure of difference of potential between two points.It is again measured in Volts. It causes the flow of electrons in a conductor from high potential to low potential.

Current :

Flow of electrons in a conductor is called current. Rate of flow of electrons is measured in Ampere.it is denoted by symbol I.

Resistance :

It is the property of matter by virtue of which it opposes the flow of electrons. It is measured in Ohms. More the resistance means less the flow of current at the same potential difference. Resistance of different materials is different. Copper causes less resistance than Iron and Iron causes less resistance than wood. thus the current flows easily in copper and too much less in wood.

Relation between Voltage,Current and Resistance ( Ohm's law ) 

Ohm's law states that potential difference between two point of a conductor is directly proportional to the current  flowing through it while keeping the other parameters (temperature etc) kept constant.


                 V    I

where

  V       Potential Difference (Volts)
  I        Current (Ampere)
   Sign of proportionality

To remove the sign of proportionality we have to add constant on the right side of equation.

V = R X I     .....................eq(1)

Where R is the Resistance of Conductor. The value of R can be calculated as

R= V/I          ....................eq.(2)


From eq (2) we can say that in a conductor if potential difference across a conductor is 1 V and current flowing throw it is 1 A then the resistance of that conductor is said to be 1Ω.

Power :  

Power is the amount of current times the voltage level at a given point measured in wattage or watts.

means

P= VI

Heat :

Current flowing throw a conductor also produces heat. which can be calculated as

H=P . t

where t is time is seconds.

and Heat (H) is calculated in joules (J)


Other relations between V,I,R,P,H and t are

R=V/I                         V=I.R                 I=V/R

P=V.I                           P=I² .R               P=V²/R

H=P.t                          H=V.I.t               H=V²/R . t

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