JNTUH Electrical Circuits Study Materials by Adrobook

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INTRODUCTION:

UNIT 1

With increase in population the need for electricity also increases therefore it is necessary to rise number of electrical engineers. The electrical engineering mainly deals with generation , transmission and distribution of electricity.

Electrical circuits is the basic and fundamental subject which lays path to understand subjects related to generation , transmission and distribution of electricity.

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In the first unit we shall deal with what is electrical circuit and formation of electrical circuit. Knowing or unknowing we come across electron in our life daily, studying the properties of these electrons leads to the terms voltage, current and power. Hence the basic definitions of voltage , current , power and energy are studied here.

Basic Parameters:

Here we shall deal with three basic parameters so called RESISTOR, INDUCTOR AND CAPACITOR with out which formation of electrical circuit is highly difficult. What are these element? , the properties, beahviour, relation between voltage and current in these elements are studied . later formation of electrical circuit and network using these elements is studied. Formation of electrical circuits using these elements depends mainly on the nature of supply. For DC source networks one can use only resistors and for AC source networks one can combinations of RLC elements. Inductor and capacitor are also called as energy storing elements. Later we shall see classification of elements from the knowledge of this one can able to identify the element required to form that particular circuit.

Formation Of Electrical Circuit Or Network:

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There are several combinations of we can use to form electrical network using RLC, they are only R, R-L, R-C, L-C, R-L-C and these arrangements can be done in different types like series, parallel, series-parallel and parallel –series connections.

Source:

To lead the network we need source , where source is defined as an active element which delivers power. Mainly there are two types of source– voltage and current source, but practically voltage source exist, again these sources are classified as DC and AC source. General sources are called as independent sources and their exist depend sources also which dummy one.

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Basic Laws:

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The statements of ohm’s law, kirchoff’s laws are seen here. With the knowledge these laws one can be able to study the behavior of network, type of source required depending on connection of elements.

Network Reduction Techniques: These reduction techniques are used to reduce any complex network into simple one and then simplify for required result. These are used to determine equivalent resistance, source current, current through each element, voltage across each element and total power deliver and total power received by the elements. Some of techniques are named as mesh analysis, nodal analysis, source transformation and star-delta transformation.

Conclusion:

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By the end of this unit one can understand the basic parameters to form electrical network, formation of electrical network, simplifying the network using different reduction techniques to determine voltage, current and power in the network.

UNIT 2

INTRODUCTION:

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In general transmission of Dc power is difficult and not economical and even Dc generation is also less , hence more units are required to meet demand to overcome above drawbacks the AC generation came into existence , therefore before going to study in depth about Ac generation, transmission and distribution it is necessary to have the knowledge of alternating quantities and their importance in power systems.

Alternating Quantity:

In the definition alternating quantity is one whose value changes from time to time , if this change periodically happens then it is called as periodic alternating quantity otherwise nonperiodic alternating quantity. There are many periodic functions but best one sinusoidal function. Hence generally sine function is used to represent periodic waveform because of following reasons,

ď&#x192;¨ It can be easily generated. ď&#x192;¨ Integration and differentiation of sine function is again sine function only.

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Hence we shall study what is sine function?, representation of sine function, definitions related sine functions and its applicability in power system networks. Some of the definitions related to sine wave are peak value, peak to peak value, average value, RMS value, peak factor and form factor.

AC Circuit:

An AC circuit consists of an source, RLC elements and connecting wire, here AC source could be an alternating voltage source or alternating current source. Before formation of AC circuit one should have the knowledge of reactance, impedance, susceptance and admittance offered by R-L-C parameters. In the definitions :

 Impedance is the ratio of source voltage to source current for the circuit and for the element ratio of voltage across element to current flowing through element. Impedance is analogues to resistance in DC circuits.  Admittance is reciprocal of impedance in definition and is analogues to conductance in Dc circuit. Power In AC Circuit:

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In the Dc circuits the power is given as product of voltage and current but the case is different in AC circuit. The behavior of AC circuit studied in terms of reactance, resistance and impedance offered by the circuit. Depending on this behavior the Ac circuit is associated with three powers , they are—active , reactive and apparent power.

 Active power – because of resistive nature of circuit.  Reactive power -- because of reactance nature of circuit.  Apparent power – represented by impedance of circuit.

But the only usefull power by the load always active power, that is why it is also called as true power, average power , ohmic power and active power.

The power concept can be easily understood by power triangle

B -- reactive power C – apparent power

Where, A – active power

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In the similar fashion impedance triangle can also be represented

Where, A – resistance B

B -- reactance C – impedance

CONCLUSION:

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By the end of this unit student will be able to understand what is AC quantity?, representation elements in AC circuit, what are the AC sources?, how to represent Ac circuit?, what is the behavior of AC circuit? And how it is applicable to real power systems?

UNIT 3

INTRODUCTION: From the unit 2 we understood the AC circuits. In the first part of unit 2 we shall locus diagram, in the next part electrical resonance and in the last part of the unit we shall see magnetic circuits. Locus Diagram:

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Locus diagram is the graphical or plot representation of electrical circuit. Locus diagram is drawn for Ac circuits, where the behavior of Ac circuit is given in terms of total impedance. Impedance of the circuit is variable depending on variations in resistance or reactance. The variations in resistance is done by rheostat and in reactance is done by frequency.

How to draw the locus diagram?

 Firstly represent the impedance of the circuit either resistance as variable or reactance as variable.  At each and every variation of resistance or reactance represent the resultant impedance .  Continue this for the variations of resistance or reactance from 0 to infinite.  Then join all the tips of resultant with smooth forming semi circle.  This plot representing the behavior of circuit is called as locus diagram.

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Locus diagram got applications of designing efficiency of the machine.

the machine, determining the

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Electrical Resonance:

In general resonance is defined the second body will come under influence of first body leading maximum . Similarly when electrical circuit is under resonance the maximum current flows through the circuit, which may also called as electrical resonance. In the definition the electrical circuit is said to be under resonance if total impedance offered by the circuit is purely resistive, the condition for electrical resonance is net reactance of the circuit must be zero. This phenomenon is studied for both series and parallel circuits. The resonance topic is also useful in determining the bandwidth and quality factor of the circuit. Resonance got wide applications in communications eg: radio frequencies i.e the desired signal can be transmitted at desired frequency at desired band of frequencies.

Magnetic Circuits: Before going for magnetic circuit one must have the knowledge of coil and its properties like self inductance, mutual inductance, energy stored and definitions like flux linkage, flux density, field intensity, magneto motive force(mmf), reluctance and permeaance.

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Faradays laws also plays important role while studying about magnetic circuit. In general, the emf induced in the coil is given by faradayâ&#x20AC;&#x2122;s law of electro-magnetic induction. The total emf induced in coil is given as sum self induced emf and mutually induced emf. To determine expression for total induced emf in the coil we can use right hand thumb rule or dot convention. During this we may come across co-efficient of coupling which is the index amount of flux linking with second coil.

In the definition magnetic circuit is formed when an core provides closed path for the magnet flux developed in the coil. Then we shall see what is the total mmf required to develop flux in coil?, what is the total reluctance of the core?. Later this study is extended to series, parallel magnetic circuits and then to composite magnetic circuits.

Conclusion:

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By the end of this unit student will be able to form the locus diagram for any electrical network, can design the bandwidth for the electrical network and then gets the concept of magnetic circuit which is very much required to study further subjects in power systems.

UNIT 4 INTRODUCTION:

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It is easy to study the behavior of electrical network in terms of voltage, current and power using different network reduction techniques for simple networks i.e if number of mesh are <=4 and number of nodes are <= 4, but if the numbers of mesh or nodes are more then 10 then these are techniques are not suggestable. Here comes importance of graph theory or network topology .

Network Topology:

Incidence matrix:

Network topology is the technique where all the elements of the network are represented by straight lines and cross lines with crossover and without cross over and then studying the behavior network using different matrices. Before going for these matrices one should know the definitions like graph, oriented graph and non-oriented graph, tree, co-tree, degree, rank, twigs, links, tieset and cut-set matrices.

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Incidence matrix is formed between number of nodes and number of branches , this matrix is mainly aimed to construct or design any complex network very easily . This matrix is also used in determining rank of the circuit.

Tie-set Matrix:

The tie-set matrix is formed between number link currents and number of loop currents. This matrix aimed to write the mesh equations for any complex network. This is also called as fundamental or basic tie-set matrix.

Cut-set Matrix: The cut-set matrix is formed between number twig voltages and number of branch voltages. This matrix aimed to write the nodal equations for any complex network. This is also called as fundamental or basic cut-set matrix.

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With these matrices formed we can write code in the system and then can study the behavior of the complex network.

Dual And Duality:

To reduce the complexity of the circuit some times we can transform series network into parallel and vice-versa. This can be done using duality. Dual network is the duplicate of the original network without changing the characteristics of the network. For the original network to convert into dual network , we shall use—

Resistance –dual element—conductance Inductance –dual element—capacitance

capacitance –dual element—inductance

Series –dual element—parallel

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Conclusion:

Short circuit–dual element—open circuit.

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By the end of this unit student can be able to write the mesh and nodal equations for any complex electrical network.

UNIT 5 INTRODUCTION:

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Here we are going to deal with DC and AC theorems. These theorems are useful in reducing complexity of the network, to design the network, to design the load resistance or impedance and to find the response in any element. The different theorems we are going to see in this unit are tellegen’s, super-position, thevenin’s, nortan’s, reciprocity, milliman’s and compensation theorem.

Discription:

Let us see in brief the importance of each theorem

Tellegen’s theorem---- to verify whether power delivered is equal to power received are not because no Circuit exist without this.

Thevenin’s theorem--- to reduce complexity of the network and to design load resistance.

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Nortan’s theorem------ to reduce complexity of the network and to design load resistance.

Super-position theorem- to determine the response in any element very easily and due to individual Sources.

Reciprocity theorem--- it is useful in communications network to check whether the network reciprocity Are not.

Milliman’s theorem--- to reduce complexity of the network and to design load resistance.

Compensation theorem- to determine the behavior of network for small variations in the resistance.

CONCLUSION:

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By the end of this unit student can be able to use appropriate theorem for finding response, designing element and to find variations in the response of the circuit.

UNIT 6 INTRODUCTION:

THE MOST IMPORTANT PARAMETER AROUND WHICH THE ENTIRE POWER SYSTEMS REVOLVES IS RESISTANCE OF THE MATERIAL. IF AN MATERIAL AS NATURE OF RRESTRICTING THE CURRENT THEN IT IS TERMED AS RESISTOR OTHERWISE CONDUCTOR.

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DEFINATION---THE PROPERTY OF OPPOSING ELECTRONS BY AN MATERIAL IS CALLED AS RESISTANCE, WHICH IS REPRESENTED IN TWO WAYS----EITHER IN TERMS OF RESISTIVITY, LENGTH ,AREA OR IN TERMS OF VOLTAGE APPLIED AND CURRENT FLOWING THROUGH IT.

PROCESS---TO AN MATERIAL WHEN EXTERNAL PRESSURE IS APPLIED( VOLTAGE) TILL THEN RANDOMLY MOVING ELECTRONS TENDS MOVE IN ONE PARTICULAR DIRECTION FROM CATHODE OT ANODE, DURING THIS TRAVEL ELECTRONS TENDS TO COLLIDE THE ATOMS OF MATERIAL THEIR BY LOOSING KINETIC ENERGY AND NOT REACHING THE ANODE, THIS IS CALLED AS RESISTANCE, AS NUMBER OF COLLISIONS INCREASES THE RESISTANCE PROPERTY OF MATERIAL ALSO INCRASES.

DISCRIPTION:

THE MEASUREMENT OF RESISTANCE GOT VERY IMPORTANCE IN POWER SYSTEMS AS IT PLAYS KEY ROLE IN POWER SYSTEM OPERATION AND CONTROL. DEPENDING ON RANGE MEASUREMENT OF RESISTANCE IS CLASSIFIED INTO THREE TYPES---

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1. LOW RANGE RESISTANCE. 2. MEDIUM RANGE RESISTANCE. 3. HIGH RANGE RESISTANCE.

LOW RANGE RESISTANCE:

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TO MEASURE LOW RANGE THE DOFFERENT METHODS ARE 1. VOLT-AMP METHOD 2. POTENTIOMETER 3. KE LVIN DOUBLE BRIDGE

WE SHALL STUDY DEEP INTO THESE METHODS AND CHOOSE WHICH METHOD IS BEST SUITABLE FOR MEASUREMENT OF RESISTANCE. EVERY METHODS GOT THEIR OWN ADVANTAGES, DISADVANTAGES AND LIMITATIONS.

MEDIUM RANGE RESISTANCE:

TO MEASURE MEDIUM RANGE THE DOFFERENT METHODS ARE 1. VOLT-AMP METHOD 2. SUBSTITUTION METHOD 3. WHEAT STONE BRIDGE.

HIGH RANGE RESISTANCE: TO MEASURE HIGH RANGE THE DOFFERENT METHODS ARE

VOLT-AMP METHOD MEGA OHM BRIDGE OHMMETER. MEGGER. LOSS OF CHARGE METHOD

1. 2. 3. 4. 5.

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WE SHALL STUDY DEEP INTO THESE METHODS AND CHOOSE WHICH METHOD IS BEST SUITABLE FOR MEASUREMENT OF RESISTANCE. EVERY METHODS GOT THEIR OWN ADVANTAGES, DISADVANTAGES AND LIMITATIONS.

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CONCLUSION:

WE SHALL STUDY DEEP INTO THESE METHODS AND CHOOSE WHICH METHOD IS BEST SUITABLE FOR MEASUREMENT OF RESISTANCE. EVERY METHODS GOT THEIR OWN ADVANTAGES, DISADVANTAGES AND LIMITATIONS.

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THE DIFFERENT WAYS TO MEASURE RESISTANCE OF MATERIAL UNDER DIFFERENT CONDITIONS IN THE CHOOSEN ARE MEASURED WITH MOST PRECISIONEDLY . ALSO THE ERROR IN THE MEASUREMENT OF RESISTANCE USING VARIOUS METHODDS ARE THOROUGHLY ANALYSED HERE AND BEST METHOD IS SUGGESTED.

UNIT 7

INTRODUCTION: THE OTHER TWO PARAMETERS WHICH RULE THE ELECTRICAL ENGINEERING ARE INDUCTOR AND CAPACITOR.

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INDUCTOR IS AN CONSTRUCTION OF WIRE IN THE TWISTED FORM EXHIBITING INDUCATNCE PROPERTY, THIS INDUCTOR ELEMENT GOT APPLICATIONS IN DESIGN OF MACHINES FOR GENERATION, FOR FILTERING, FOR STORING ENERGY ETC.THIS STORES ENERGY IN THE FORM OF MAGNETIC FIELD.INDUCTOR IS ASSOCIATED WITH STORING FACTOR.

CAPACITOR IS THE CONSTRUCTION OF TWO PARALLEL PLATES SEPERATED BY INSULATION MEDIUM EXHIBITING PROPERTY OF CAPACITANCE, WHICH GOT APPLICATIONS IN POWER SYSTEM TRANSMISSION AND DISTRIBUTION. THIS STORES ENERGY IN THE FORM OF ELECTRIC FIELD.CAPACITOR IS ASSOCIATED WITH LOSS FACTOR.

DISCRIPTION:

HENCE TO MEASURE INDUCTANCE AND CAPACITANCE AC BRIDGES ARE EVOVLED . AC BRIDGES CONSISTS OF FOUR ARMS, SOURCE AND DETECTOR. EACH ARM IS REPRESENTED WITH IMPEDANCE. SOURCE IS AN BRIDGE OSCILLATOR , POWER LINE ETC.

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MEASUREMENT OF UNKNOWN INDUCTANCE:

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 CONSTRUCTION AND DERIVATION OF ALONG WITTH THE PHASOR DIAGARM MAXWELL’S BRIDGE  ADAVTAGES AND DISADVANTAGES OF MAXWELL’S BRIDGE  CONSTRUCTION AND DERIVATION OF ALONG WITTH THE PHASOR DIAGARM HAYS BRIDGE  ADAVTAGES AND DISADVANTAGES OF HAYS BRIDGE  CONSTRUCTION AND DERIVATION OF ALONG WITTH THE PHASOR DIAGARM ANDERSON’S BRIDGE  ADAVTAGES AND DISADVANTAGES OF ANDERSON’S BRIDGE  CONSTRUCTION AND DERIVATION OF ALONG WITTH THE PHASOR DIAGARM OWEN’S BRIDGE  ADAVTAGES AND DISADVANTAGES OF OWEN’S BRIDGE MEASUREMENT OF UNKNOWN CAPACITANCE:

 CONSTRUCTION AND DERIVATION OF ALONG WITTH THE PHASOR DIAGARM DESAUTY’S BRIDGE  ADAVTAGES AND DISADVANTAGES OF DESAUTY’S BRIDGE  CONSTRUCTION AND DERIVATION OF ALONG WITTH THE PHASOR DIAGARM WEIN’S BRIDGE  ADAVTAGES AND DISADVANTAGES OF WEIN’S BRIDGE  CONSTRUCTION AND DERIVATION OF ALONG WITTH THE PHASOR DIAGARM SCHERING BRIDGE  ADAVTAGES AND DISADVANTAGES OF SCHERING BRIDGE

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CONCLUSION:

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THE AC BRIDGES GOT VERY MUCH IMPORATNCE IN MEASURING UNKNOWN PARAMETERS LIKE INDUCATNCE, CAPACIATNCE AND THEIR STORAGE , LOSS FACTOR. OTHER THAN USING RLC METERS TO MEASURE THESE PARAMETERS AC BRIDGES ARE COMPARISON METHODS WHICH GIVES VERY PRECISION VALUE. EVERY BRIDGE GOT THEIR OWN ADVANTAGES AND DISADVANTAGES TO OVERCOME THAT NEW BRIDGE IS EVOVLED .

UNIT 8

INTRODUCTION: OTHER THAN MAJOR MEASURING DEVICES THEIR ARE OTHER DEVICES ALSO WHICH ARE USED OCCASIONALLY. OUT OF THAT WE ARE GOING TO DEAL WITH BALLASTIC GALVANOMETER AND FLUXMETER. DISCRIPTION:

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HERE WE SHALL SEE THE DEFINATION OF BALLASTIC GALVANOMETER, CONSTRUCTION AND OPEARTION BALLASTIC GALVANOMETER, ADVANTAGES OF DISADVANTAGES OF BALLASTIC GALVANOMETER, EQUATION OF MOTION FOR BALLASTIC GALVANOMETER. LATER WE SHALL SEETHE CONSTRUCTION AND OPEARTION OF FLUX METER, ADVANTAGES OF DISADVANTAGES OF FLUX METER.

COMPARISION BETWEEN BALLASTIC GALVANOMETER FLUXMETER.APPLICATIONS OF BALLASTIC GALVANOMETER AND FLUXMETER

DETERMINATION OF B-H LOOP METHODS

AC TESTING

ï&#x192;¨ IRON LOSS OF BAR

CORENSTRUCTION LOSS MEASUREMENT

CONCLUSION:

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THEERE FOR THE IMPORATNCE OF BALLASTIC GALVANOMETER AND FLUXMETER IN POWER SYSTEMS ARE STUDIED, AND THEIR IMPORTANCES ARE COMPARED .

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