introduction to electrical engineering 1.pptx

8/9/2019 INTRODUCTION TO ELECTRICAL ENGINEERING 1.pptx

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INTRODUCTION TO ELECTRICAL ENGINEERING 1GEC 211.

Topic :Introduction to circuit theory

Highight : Ch!rge !nd current"

Re#i#tor"

Independent !nd dependent #ource#" Ter$# !nd de%nition#"

Oh$# !&"

'irchho()# circuit !: 'irchho()# current !nd*ot!ge !"

Loop !nd $e#h current !n!y#i#"

Nod! or +unction !n!y#i#"

,ource tr!n#-or$!tion. E!$pe#/ tutori! 0ue#tion#.


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An eectric circuit i# ! co#ed p!thco$$encing !t ! point in #p!ce !nd

ter$in!ting !t the #!$e point. The ter$ oop or co#ed oop or $e#h $!y

e u#ed to de#crie the co#ed p!th. A good no&edge o- the -und!$ent!# o-

circuit theory -!ciit!te# ! etter gr!#p o-Eectric! !nd eectronic# #u+ect# incudingCo$$unic!tion Engineering.

Charge and Current Ch!rge i# ! -und!$ent! !nd ch!r!cteri#tic

property o- the ee$ent!ry p!rtice# th!t$!e up $!tter. Eectron#" proton# !ndneutron# !re the p!rtice# cont!ined in !$!tter.


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An !to$ i# de#cried !# h!*ing ! po#iti*eych!rged nuceu# #urrounded y ! coud o-

neg!ti*ey ch!rged eectron#" ! neutr! !to$h!# !n e0u! nu$er o- oth the proton# !ndeectron#.

,u#t!nce# !re c!##i%ed on the !#i# o- the

-reedo$ o- $o*e$ent o- the eectric ch!rge#&ithin the$.

3e h!*e conductor# &hich !o& -ree 4o& o-eectron in it"

In#u!tor# &here the eectron# !re rigidyounded to the nuceu# #uch th!t it i# note!#iy det!ch!e y eectric %ed.

In et&een the conductor# !nd the in#u!tor!re the #e$i5conductor# &ho#e propertie# -!


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The ch!rge in ! conductor i# denoted y!nd the unit o- ch!rge i# Couo$ 6C7.

The r!te o- ch!nge o- ch!rge# or 4o& o-ch!rge# in ! conductor i# ter$ed current.The #y$o o- current i# &ith unit o-$e!#ure$ent gi*en !#

RE,I,TOR R!te o- 4o& o- current in ! #u#t!nce

depend# on the re#i#t!nce o- #u#t!nce.

,o$e #u#t!nce# !o& unhindered 4o& o-current through the$" other# o(eroppo#ition.

The oppo#ition o(er# to the 4o& o- current

in ! #u#t!nce i# &h!t i# c!ed !


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The #u#t!nce &ith thi# property i# c!edre#i#tor.

A re#i#tor i# lineari- it# *ot!ge5currentre!tion#hip i# de#cried y ! straightline" &hie ! non5ine!r re#i#tor h!# curvedi(erent -ro$ the #tr!ight ine.

Non5ine!r re#i#tor# h!*e &ide !ppic!tion#in negative resistance devices!nde!$pe# incude recti%c!tion" in i$itingcurrent !nd *ot!ge" -re0uency

$utipic!tion etc.

&here i# c!ed conduct!nce" the reciproc!o- re#i#t!nce.

I-" ! ine!r re#i#t!nce i# #!id to e ! #hort


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INDE9ENDENT AND DE9ENDENT ,OURCE,The %gure eo& depict# !n !ritr!ry net&or

N ecited y ! #ource o- eectric energy. I- thepre#cried potenti! energy i# $!int!ined !t! *!ue" #!y " the #ource o- energy $!y ede#ign!ted !# ! con#t!nt *ot!ge #ource. Thi#

potenti! i# #uppo#ed to e un!(ected y the*!ue o- current 4o&ing into the net&or. Onthe other h!nd" i- the #ource current i#$!int!ined irre#pecti*e o- the potenti!

di(erence" #uch ! #ource i# c!ed ! con#t!ntcurrent #ource.


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An independent #ource i# ! #ource 6currentor *ot!ge7 &ho#e *!ue i# not ! -unction

o- !n etern! condition i.e. it# *!ue i# notdependent on the *!ue o- !nother0u!ntity &ithin the circuit.

I- the current or *ot!ge o- ! #ource

depend# on the *ot!ge or currente#e&here in the circuit" it i# re-erred to !#! dependent or controed #ource.

Controed #ource# !re o-ten -ound in

eectronic circuit#. They $!y e either *ot!ge or current !nd

$!y e controed y !nother *ot!ge orcurrent !# the c!#e $!y e.


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TER;, AND DE


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Lumped Network: ! net&or in &hichphy#ic!y #ep!r!te re#i#tor#" inductor#"

c!p!citor#" etc. c!n e repre#ented. The*!ue# o- the re#i#t!nce" induct!nce etc.!re u#u!y u$ped together.

Distributed Network: Re#i#t!nce"

Induct!nce" etc. !re repre#ented !#di#triuted p!r!$eter#. They !reeectric!y #ep!r!ted !nd repre#ented !##ep!r!te ee$ent#.

Passive Network: Net&or cont!iningcircuit ee$ent &ithout !ny #ource.Re#i#t!nce" induct!nce !nd c!p!cit!nce

!re p!##i*e ee$ent#. Active Network: net&or cont!inin


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Line!r Ee$ent: ee$ent in &hich the re!tionet&een current !nd *ot!ge i# ine!r.

Line!r Net&or: di(erenti! e0u!tion re!tingthe in#t!nt!neou# current or *ot!ge i# !ine!r e0u!tion &ith con#t!nt coe=cient#.

Loop: thi# i# -or$ed y ! #et o- r!nche#-or$ing ! co#ed p!th in the net&or. I- !nyo- the r!nche# i# o$itted" the re$!iningr!nche# ce!#e to -or$ ! co#ed p!th.

;e#h : i- the oop cont!in# no other oop" it$!y e re-erred !# ! $e#h. A $!+or oop $!ycont!in $ore th!n one co#ed p!th. I- there i#ony one co#ed p!th" #uch i# etter re-erred

to !# ! $e#h.


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Node or Junction : ! ter$in! o- !ny r!nch o-net&or " or ! ter$in! co$$on to t&o or $orer!nche#.GN!AL P!"P!#$% "& LC#!$C

C$!C'$#% Eectric circuit po##e## -our -und!$ent!

eectric! propertie#" n!$ey re#i#t!nce"

induct!nce" c!p!cit!nce !nd e!!geconduct!nce. Theoretic!y" pure re#i#tor#" inductor#" !nd

c!p!citor# !re concei*ed -or !n!y#i#.

A re#i#tor $!y po##e## !p!rt -ro$ re#i#t!ncecert!in !$ount o- re#idu! induct!nce !ndc!p!cit!nce !# &e.

,i$i!ry" !n inductor $!y po##e##" !p!rt

-ro$ the induct!nce" cert!in !$ount o-


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Circuit ee$ent# !re c!ed i!ter! i- the*ot!ge5current re!tion#hip re$!in#unch!nged &hen the po!rity o- the !ppied*ot!ge !nd the direction o- the current !rere*er#ed.

I- ho&e*er" the re!tion et&een the current

!nd *ot!ge i# not the #!$e on re*er#! o-the direction" the circuit ee$ent# !re c!eduni!ter!" e.g. !cuu$ !nd #e$i5conductordiode#.

ot!ge !nd current #ource# !re !cti*eee$ent# !nd !re independent #ource# i- thecurrent !nd *ot!ge in the circuitre#pecti*ey do not !(ect the *ot!ge !nd

current o- other #ource# in the circuit.


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An ide! *ot!ge #ource h!# ! con#t!nt!$pitude *ot!ge !t the output ter$in!#irre#pecti*e o- the $!gnitude o- the current

#uppied y it. ,i$i!ry" there i# no po&er di##ip!tion in

the #ource i.e. it# e0ui*!ent #erie#re#i#t!nce i# >ero.

In the c!#e o- pr!ctic! *ot!ge #ourceconnected in ! circuit !# #ho&n in thedi!gr!$ eo&" the ter$in! *ot!ge i# .

I- the current #uppied y the gener!tor i# "then the ter$in! *ot!ge !*!i!e -or theo!d i# gi*en y the re!tion?


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OH;), LA33hen the current in ! conductor i# #te!dy !nd

there i# no E;< 6eectro$oti*e -orce7 &ithinthe conductor" the *!ue o- the potenti!di(erence 6*ot!ge7 !cro## the ter$in!# o-the conductor i# proportion! to the current"i.e.

3here i# the potenti! di(erence !nd I i# the

current.


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The coe=cient o- proportion!ity R i# there#i#t!nce o- the conductor.


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($!C))"&&*% C$!C'$# LA+%T&o -und!$ent! circuit ! $o#ty u#ed !re?

'irchho()# current !& 6'L7 !nd 'irchho()# *ot!ge !& 6'L7

'irchho()# current !&: the !ger!ic #u$ o- !the in#t!nt!neou# current !t ! +unction or nodein !n eectric circuit i# >ero.

'irchho()# ot!ge !&: the !ger!ic #u$ o-the in#t!nt!neou# *ot!ge# !cting !round !nyco#ed p!th in !n eectric circuit i# >ero. Or the

!rith$etic #u$ o- the *ot!ge drop# !round !co#ed p!th i# e0u! to the !rith$etic #u$ o-the *ot!ge ri#e# !round the p!th.


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,TEADB ,TATE D.C CCT ANALB,I,

Circuit# c!n e re#o*ed yThe Direct ;ethodU#ed !#ic!y -or #i$per circuit# Incude#:5 Oh$)# L!&" L! o-

re#i#tor#6 #erie# 9!r!eco$in!tion#" ot!ge Di*ider Rue"Loop An!y#i#" Nod! An!y#i#",uperpo#ition " Co$pen#!tion"Reciprocity Theore$# " etc.

Net&or Reduction ;ethodU#ed -or oth #i$pe !nd co$pe

circuit#.Incude# :5 Det!5 ,t!r Tr!n#-or$!tion"

,t!r5Det! Tr!n#-or$!tion" The*enin)#theore$" !nd Norton)# Theore$


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'irchho()# L!

A, (irchho-*s Current Law .(CL/:At !ny +unction in !n eectric cct" the tot! current

4o&ing to&!rd#th!t +unction i# e0u! to the tot! current 4o&ing

!&!y -ro$ the

+unction. i.eOR

In !ny eectric! net&or" the !ger!ic #u$ o- thecurrent# $eeting !t ! point 6or +unction 7 i# >ero.

$llustration$

0

$

1

$

2

$

3

$

4


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B, (irchho-*s 8oltage Law.(8L/:

In !ny co#ed oop in ! net&or" the !ger!ic #u$ o-

the

*ot!ge drop# !round the oop e0u!# the re#ut!nt

e.$.- !cting

in th!t oop.

OR

The !ger!ic #u$ o- the product o- current# !nd

re#i#t!nce in e!ch

O- the conductor# in !ny co#ed p!th6$e#h7 in !

net&or !nd the

! er!ic #u$ o- the e.$.-# in the #!$e !th i# >ero.

Ager!ic #u$ t!e# cogni>!nce o- thepo!ritie#


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DETER;INATION O< OLTAGE ,IGN

1. ,ign o- !ttery E.;.

introduction to electrical engineering 1.pptx

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