Concept of Electrical Conductivity

Period of Teaching about network theory

The scanrious/secrets present in the Network theory:-

Scanrious 1:-  In the presence of active sources
 In the presence of source all the 3-passive lumped R, L, C will always absorb the energy
When ever they ( R, L, C ) are absorbing the energy, the current through them will always flows from positive to negative terminals ( i,e high level to low level ).

Scanrious 2 :-  In the absence of active sources 
* In the absence of sources, stored energy in the memory elements ( L & C ) will be delivered to the memoryless resistances . 
Whenever L and C elements are delivering the energy, currents through them will always from positive to negative terminals ( i,e from low level to high level ).As the Resistor is always absorbing the energy, the current through it will always from positive to negative terminal.

Active Element:- The Element which can boost any electrical energy.
 Another definition :- In an electrical network, if a circuit element has the capability of enhancing the energy level of a single passing through it , then it is termed as an active element

Examples - voltage and current sources, semiconductor devices like transistor and OP-Amp etc.

Passive Element:- The Element which dissipate energy from the circuit.
Examples - Resistor, Inductor and Capacitor etc.

Basic difference between the Network and  Circuit .

Circuit :- The circuit is a closed loop path in which electric current and voltage sources flows through it.

Electric circuit

Network:- The Network is the interconnection of the circuit.

Electric Current:- The flow of charges in the circuit is called Electric current.
* Electric current is denoted by I and S.I unit is Ampere.
* It is expressed as  I = q/t.

Voltage:- The potential difference between two point charges is nothing but Voltage.
* The Voltage is denoted by V and S.I unit is 'V'.
 Resistor:-    Resistor are common elements of electrical network and electronic circuit and are ubiquitous in electronic equipment which reduce current flow  , and , at the same time time , act to lower voltage levels within circuits.

 Series Resistor:- In the series connection of the resistor , there is only one path for the flow of current in the circuit . 
* In series connection of the resistor , current will be same of the every resistor but voltage will be different of the every resistor .
* In series connection of the resistor volt meter is used .

Parallel resistor :-  In the parallel connection of the resistor , there are many  path for the flow of current in the circuit . 
* In parallel connection of a resistor , the voltage will be same in every resistor while current will be  different in every resistor .
* Series and parallel connection of the resistor as shown in figure :-

Figure :-  Series and Parallel connection of the resistors  

Ohm's Law
The Ohm's law is the mathematical relationship among electric current , voltage and resistor.
* The principle is named after German Scientist Georg Simon Ohm.
* the ohm's law is defined as the electric current is directly proportional to the voltage.
i,e  V directly proportional to I.
    V = IR
    I= V/R 
    R= V/R

LAB ACTIVITY OF ELECTRIC CONDUCTIVITY

* Testing conductivity of liquids

. Electrical conductivity of liquids can be tested by a simple activity of taking a liquid, like lemon juice, in a container, inserting electrodes in it, connecting the two electrodes to the terminals of a battery with a bulb (LED) between them. The bulb glows, indicating that lemon juice is a conductor of electricity. Several liquids can be checked for electrical conductivity in the same way.

The process of decomposition of a chemical compound in a solution when an electric current passes through it is called electrolysis. This process is due to the chemical effect of electric current .


* Testing conductivity of metal

Figure : Testing conductivity of metal

Metaltest provides electrical conductivity testing for determining the electrical conductivity of nonmagnetic metals using the electromagnetic (eddy-current) method. This test is applicable to metals that have either a flat or slightly curved surface and includes metals with or without a thin nonconductive coating. Electrical conductivity testing can be used to determine: type of metal or alloy, type of heat treatment (for aluminum this evaluation should be used in conjunction with a hardness examination), aging of the alloy, and heat damage.

By : Engineer Affan Nomani

( The writer is a research Analyst at JNTU Hyderabad & Columnist . He has been publishing in many leading newspaper such The Hans India and DC  for the last few years . we always believe that there is no need to be defensive in front of communal forces. He may be reached at affannomani02@gmail.com )