Basics of electrical and electronics engineering

Basics of electrical and electronics engineering

Analysis of DC circuit and AC circuit: 

We will cover the following topics related to basics of electrical and electronics engineering for analysis of DC and AC circuits:

Basics of electrical engineering:

•Network classification, Ohm's law, KCL, KVL

• Use star delta transformations, mesh analysis to simplify the network

• Network theorem (Superposition and Thevenin).

• Generation of AC voltage, basic principles of AC circuits

• The behavior of pure R, L, C in AC circuits, the concept and representation of phasors,

• RL, RC and RLC series circuits.

Network classification :The electric Network is the combination of circuits and electrical components (for example, batteries, resistors, inductors, capacitors, switches) 

An electric circuit composed of a closed loop, which provides a return path for the current. 

Linear power circuit, a special type consisting of only active element (voltage or current), linear distributed elements (transmission lines), an linear lumped elements (resistors, capacitors, inductors).                    

               Electric network is a combination of circuits with active and passive elements.

Active components: voltage source, current source, etc.

Passive components: resistors, capacitors, inductors, etc.

Different ways to classify the network:

Active and Passive Network:

An active network is a network containing an active source, which can be a voltage or current source. It contains one or more emf source.

A passive network is a network that does not contain active sources. There is no source of emf. It contains R, L, and C elements only.

Linear and nonlinear network:

If the signal of the network follows the superposition principle, the network is linear, otherwise it is non-linear.

A linear circuit is a circuit whose output is proportional to its input. Linear circuits are subject to homogeneity (scaling) and additivity.

Scientific calculator:Casio fx-991 ES

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Click below to download Syllabus, book pdf,ppt etc:

Basics of electrical and electronics engineering syllabus (MIT-ADTU)

Basics of electrical and electronics engineering lab manual

Basic electrical and electronics engineering pdf (book) 

Basic electrical and electronics engineering multiple choice questions  


D.C.  and AC Circuits ppt

ELECTRICAL MACHINES(Motor and 1 phase Transformer) ppt


Diode and Diode Circuits ppt(Click here)

Questions bank on Basic Electronics(Diode,BJT,Digital Electronics) and Transducer(Unit-III,IV and V)(Click here)


Digital Electronics ppt(Click here)

Questions bank on Basic Electronics(Diode,BJT,Digital Electronics) and Transducer(Unit-III,IV and V)(Click here)


Questions bank on Transducer(Unit-III,IV and V)(Click here)


Ohm's Law:

This is the most basic law of electrical engineering. As long as the temperature and other physical parameters of the conductor remain unchanged, the potential difference between the two ends of the conductor is proportional to the current flowing through the conductor.

V∝I or V = RI

Here, R = the resistance of the conductor (ohm, Ω)

The unit of resistance, ohm is defined as the resistance that allows one ampere of current to flow when a potential difference of one volt is applied to the resistance.

Another way to illustrate Ohm’s law is

 I = GV

The constant of proportionality is called conductor conductance. 

Therefore, G = 1 / R

The graphical form of Ohm’s Law,

Ohm's Law
V-I Characteristics
Here voltage is the independent variable (cause) and current is the dependent variable (effect)

 The slope of the line is the reciprocal of resistance (1 / R), which is the conductance

A conductor exhibiting linear VI characteristics has linear resistance. 

            The slope of the line is reciprocal of the resistance (1/R) and is conductance(G)


A resistor is a property of any material which always oppose the flow of current. If the current flowing through a resistor is proportional to the potential difference between both ends, the resistance of the resistor is considered linear. 

If the resistance changes with the magnitude of the voltage or current, the resistance is said to be non-linear.

R ∝l/A or R =ρl/A

Where ρ=Resistivity (ohmmeter, Ωm),l =length of the material, A=Cross sectional area of the material.

Resistance: Color coding of resistance

 Google image by: https://www.instructables.com/id

  Combination of resistance:

Combination of resistance
Combination of resistance
1. Series combination:

In  figure(a), current I flows through three resistances. Applied voltage V must be equal to the sum of the three individual voltage drops V1,V2, V3.

V =V1+V2+V3

    =  IR1+IR2+IR3

     =I (R1+R2+R3)


Where Rs = R1+R2+R3

 2. Parallel combination:

In figure (b), voltage V is equal to all three resistances.


Here, I = I1+I2+I3

              = V(1/R1+1/R2+1/R3)

             = V/Rp


 For two resistances,


Voltage Divider Rule:

Voltage division takes place in series circuit.The concept of voltage divider is very useful when analyzing the circuits. 

Consider the circuit in which two resistors R1 and R2 are connected in series with a voltage source V. The current I is given as:

I = V /(R1 + R2)

Therefore, the voltage V1 across resistor R1 is

V1 = IR1 = V R1 /(R1 + R2)

Similarly, the voltage V2 across resistor R2 is given as:

V2 = IR2 = V R2 /(R1 + R2)

Current divider rules:

Let us consider that two resistors (R1 and  R2) are connected in parallel. Therefore, a voltage V appears at both resistor.

V = I1R1 and V = I2R2

Among them, I2 = V / R2 = I1 R1 / R2

I = I1 + I2 = I1 + I1 R1 / R2 = I1 [R1 + R2 / R2]

I1 = IR2 / R1R2

The current through R2 is given as 

I2 = IR1 / R1R2

Kirchhoff's Law

The German physicist Gustav Kirchhoff (Gustav Kirchhoff) observed that these are specific examples of analyzing two basic conditions of any power circuit. The possible conditions are as follows:

The first Kirchhoff ‘s law is current law(KCL): at any moment, the algebraic sum of the current at the network node is zero. 

At any electrical junction incoming current is equal to outgoing current. Different sign positive and negative are assigned to keep the current flowing to and away from the junction.

Kirchhoff ‘s current law

The second Kirchhoff ‘s voltage law: In any case in a closed loop, the algebraic sum of e.m.f that works in the loop is equal to the algebraic sum of potential drop in the loop.


 Circuit Theorems

  • Superposition Theorem
  • Thevenin's Theorem
  • Norton's Theorem 
  • Maximum Power Transfer

Superposition Theorem:

In any linear, bilateral network having various active and passive element, the response (current, voltage) across any passive element is algebraic sum of all the responses across that element when considering one source at a time and deactivation all other source at that instant. 

          Because the circuit is linear, we can find the circuit's response to each source acting alone, and then add them together to find the circuit's response to all sources acting together. This is the so-called superposition theorem.

The principle of superposition states that the voltage across a component (or the current flowing through it) in a linear circuit is the algebraic sum of the voltage across the component (or the current flowing through it). This is due to the fact that each independent power supply works independently. .

Steps to apply the superposition principle:

1. Turn off all independent sources except one. Look for the response (voltage or current) due to a valid source.

2. Repeat step 1 for each other independent source.

3. Find the total output by adding all the results found in steps 1 and 2 above algebraically.

Let us take one example :

#Remedial Lecture-01:Solve 2 Question(Given below) on Basic Law's of Electrical Network  & Paste your photo of your solution by Clicking  on plus(+)pink sign below.Write your roll no and name on every page of your solution then take photo.

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#Remedial Lecture-02: 
Solve 3 Question(Given below) on Basic Law's of Electrical Network  & upload your scanned/photo  of your solution .Write your roll no and name on every page of your solution then take photo

#Remedial Lecture-03 & 04 : Solve Questions (Given below) on Basic Law's of Electrical Network.

MCQ Test-01Click here for MCQ Test-01. Syllabus of MCQ Test-01:D.C. CIRCUITS AND A.C. CIRCUITS:  Classification of network, Ohm's law, KCL, KVL, network simplification using star-delta / delta-star transformations, mesh analysis, network theorems (Superposition and  Thevenin).Generation of alternating voltages, fundamentals of ac circuits, behaviour of pure R, L, C in ac circuits, concept of phasor and its representation, series RL, RC and RLC circuits                                             

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