Basic Electrical Concept 1 - Current Voltage Frequency Power Resistivity


Current is the flow of electrical charge carriers like electrons. 

Current flows from negative to positive points. 

The SI unit for measuring electric current is the ampere (A). 

One ampere of current is defined as one coulomb of electrical charge moving past a unique point in a second. Electric current is widely used in household and industrial appliances

I = Q/t


Voltage is the pressure from an electrical circuit's power source that pushes charged electrons (current) through a conducting loop, enabling them to do work such as illuminating a light.


Resistivity is directly proportional to length of conductor.

Resistivity is inversely proportional to cross sectional area of conductor.

R ∝ L

R ∝ 1/A

ஃ R ∝  L/A

ஃ R = ⍴ L/A

⍴ = resistivity of conductive material

 ⍴ = R A / L 

Unit = Ω . m

Alloys have more conductivity and less resistivity.

Insulators have high resistivity and less conductivity

Resistors behavior in series and parallel


If we have 3 resistivity materials and connected in series then total voltage drop is equal to sum of individual.

V = V1 + V2 + V3

As per ohm's law ( V= IR )

IR = IR1 + IR2 + IR3

so, R = R1 + R2 + R3


I = I1 + I2 + I3

As per ohm's law ( V= IR )

V/R = V/R1 + V/R2 + V/R3

1/R = 1/R1 + 1/R2 + 1/R3


Power is defined as work done per unit time

P = Electrical energy consumed / Time

= W/t

Unit =kWh, Joule


Frequency is the number of times a sine wave repeats, or completes, a positive-to-negative cycle.

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Our house hold power has rating 50 A current, 230 V Voltage, 50 Hz Frequency. 50 Hz means 50 AC Wave cycle in 1 second.


Thanks for reading - Basic Electrical Concept - Current Voltage Frequency Power Resistivity
Naitik Patel
Industrial Guide

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