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VERIFICATION OF KIRCHOFFS LAW

AIM:

To verify Kirchoffs law in DC circuit.

APPARA T US:

Sl No: Name of the apparatus Type Range Quantity1 Voltmeter MC !"V 1# Voltmeter MC !1$V "" %mmeter MC !1% "& Rheostat 'ire !'oun( $) * $% "

PRINCIPLE:

Kirchhofs Voltage Law states that the algebraic sum of all the voltages aroundany closed path (loop or mesh) is ero.

!pplying "irchho#$s voltage la% to the &rst and the second loops in the circuitsho%n in 'igure sho%n belo% yields:

Loop : -Vs +V1 +V2 +V5 = 0 (a)Loop : -V2 +V3 +V4 = 0 (b)

Kirchhofs Current Law states that the algebraic sum of all the currents at anynode is ero.

*epartment of EEE !l+!meen Engg.,ollege- Shoranur

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!meen Engg.,ollege-

!pplying "irchho#$s current la% to the &rst four nodes in the &gure sho%nabove yields the follo%ing euations/

Node a: +0s 1 0 2 3 (a)

Node b: +0 1 0 1 04 2 3 (b)Node c: +04 1 05 2 3 (c)Node d: +0 + 05 1 06 2 3 (d)

PROCEDURE :

1+ Ma,e the connection accor(ing to the c,t (iagram#+ Keep all the three rheostats to their ma- value+"+ .witch on the DC power supply&+ /or (ifferent voltage settings of power supply* note the voltmeter an( ammeter rea(ings+

RESULT :

Kirchoffs laws are verifie(+ 0e V V1 2 V# * V V1 2 V" * 0 01 2 0#


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CIRCUIT DIAGRAM:

TABULAR COLUMN:

.3+N4+

V5v6

V15v6

V#5v6

V"5v6

015%6

0#5%6

0"5%6

VV12V#5v6

VV12V"5v6

01 0# 20"5%6

SAMPLE CALCULATIONS:

Voltmeter rea(ings V 7++voltsV1 7++voltsV# 7++voltsV" 7++volts

V1 2 V# 7++volts%s per KV3* V V1 2 V# 7++ volts


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ie KVL is verified.

%mmeter rea(ings01 7++ampere

0# 7++ ampere0" 7++ ampere 01 2 0# 7++ ampere

%s per KC3* 0 01 2 0# 7++ ampere

ie KCL is verified.


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QUESTIONS/ANS W ERS:

Ques 'hat is the statement of ,irchhoffs first law8A!s The sum of the currents entering at any 9unction is e:ual to the sum of the currents

leaving the 9unction+

Ques %ccor(ing to Kirchhoffs secon( law* the alge;raic sum of all 0R (rops an( emfs in any cloop of a networ, is e:ual to7A!s 0t is e:ual to

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E"PERIMENT NO #

AIM: TO VERI$% T&EVENIN'S T&EOREM

APPARA T US :DC N=T'4RK K0T %ND C4NN=CT0N? 3=%D.

T&EOR%: T@=V=N0N. T@=4R=M as applie( to the (c networ, c,t may ;e state( as the cuflowing through a loa( resistance R3 connecte( across any two terminals % an( A of a linear ;ilnetwor, is given ;y VT@ B RT@2R3 where VT@ is the open c,t voltage an( RT@ is the internal resisof the networ, from terminal % to A with all voltage sources replace( with their internal resistancecurrent sources with infinite resistance+

CIRCUIT DIAGRA M :

PROCEDURE:

1+ To fin( the current flowing through the loa( resistance R3 as shown in fig+ Remove R3 fromc,t temporarily an( leave the terminals % an( A open circuite(+

#+ Calculate the open c,t voltage Vth which appears across terminal % an( A+i+ Vth0+Rth

This is calle( thevenins voltage+"+ Now calculate RthR1 R# BR12R#.This is calle( thevenins resistance+&+ Calculate 03 VthB5R32Rth6+$+ Vth =R#BR12R# .

OBSERVATION TABLE:


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.R+N4 %30=DV43T%?=5volts6

Vth5volts6Theo+

Vth5volts6ract+

Rth54hms6

035m%6ract+

035m%6Theo+

R=.3


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RESULT: T@=V=N0N. T@=4R=M has ;een verifie(+

DISCUSS I ON: 0n T@=V=N0N. e:uivalent circuit thevenins e:uivalent voltage is in seriesthevenins resistance an( the loa( resistance+

PRECAUTIONS:

&+ .'0TC@ 4// the supply when not in use+$+ Rea(ing shoul( ;e ta,en carefully+E+ %ll connections shoul( ;e tight an( correct+

QUI ( /ANSWER:

Ques To what type of c,t thevenins theorem is applica;leA!s 3inear an( ;ilateral

Ques 'hat is the use of thevenins theorem8A!s To convert the comple- c,t into a voltage source an( a series resistance

Ques @ow is the Rth is connecte( with the c,t8A!s 0n series

Ques @ow is the Rth is connecte( with the loa( resistance8A!s 0n series

Ques 'hat mo(ification is (one in galvanometer to convert it into a ammeter8A!s % large resistance in parallel

Ques 'hat mo(ification is (one in the galvanometer to convert it into a voltmeter8A!s % series resistance

Ques Resistance is a n active element or the passive8

A!s assiveQues @ow will you calculate the Rth8A!s The resistance ;etween the two terminals

Ques 0n place of current source* what is place( while calculating Rth8A!s Replace current source ;y open c,t


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Ques 0n place of voltage source which electrical parameters is place(8A!s % short c,t+


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E"PERIMENT NO )

AIM:TO VERI$% NORTON'S T&EOREM

APPARA T US: DC N=T'4RK K0T *C4NN=CT0N? 3=%D.+

T&EOR%: N4RT4N. T@=4R=M replaces the electrical networ, ;y an e:uivalent constant cusource an( a parallel resistance+nortons e:uivalent resistance RNR1FR#BR12R#%ctual loa( current in the circuit 031Theoretical loa( current 03#0.CFRNB5RN2R36* 0.C is the short circuit current.

CIRCUIT DIAGRA M :

PROCEDURE :

1+ Connect the c,t as per the c,t (iagram#+ Remove the loa( resistance"+ /in( the Nortons resistance Rn&+ Measure the Nortons current 0n$+ Now measure the current in the loa( resistance (irectlyE+ /in( out the current in the loa(

G+ sing formula fin( out the current in the loa( resistanceH+ Verify that these two are e:ual+

OBSERVATION TABLE:


SRNO APPLIED

VOLTAGE

*v+,-s.

IN*A.

RN*).

IL0*A.

IL#*A.

ERROR

IL0 -- IL#

RESU

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RESULT : Nortons theorem is verifie(

DISCUSS I ON :0n N4RT4N. e:uivalent circuit the nortons current source is in parallel N4RT4N. resistance an( the loa( resistance+

PRECAUTIONS:

G+ %ll connections shoul( ;e tight an( correct+H+ .'0TC@ 4// the supply when not in use+I+ Rea(ing shoul( ;e ta,en carefully+

QUI(/ANSWER:

Ques To what type of networ, Nortons theorem applica;le8A!s Two terminal linear networ, containing in(epen(ent voltage an( current sources+

Ques @ow is Rn connecte( to 0n8A!s 0n the parallel

Ques 'hat is place( in place of voltage sources while calculating the Rn8A!s Their internal resistance replaces these+

Ques ?ive an e-ample of unilateral c,t8A!s Dio(e rectifier

Ques 'hat is unilateral c,t8A!s 'hose characteristics changes with the change in (irection of operation

Ques ?ive one e-ample of the ;ilateral nBw8A!s Transmission lines

Ques 'hat is the limitation of ohms law8A!s rovi(e( physical con(itions (o not change

Ques 'hat is the reason that groun( pin are ma(e of greater (ia in the plugs8A!s RJ3B%

Ques 'here is the voltage (ivi(er rule applica;le8A!s Two resistance in series

Ques 'here is the current (ivi(er rule applica;le8A!s 'hen there are two resistances are in parallel+


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E"PERIMENT NO 1

AIM: TO VERI$% RECIPROCIT% T&EOREM

APPARA T US: DC N=T'4RK T@=4R=M K0T %ND C4NN=CT0N? 3=%D.

T&EOR%: Reciprocity theorem can ;e state( as in any ;ilateral linear networ, if a source of emany ;ranch pro(uces a current 0 in any other ;ranch then the same emf = acting in the secon( ;will pro(uce the same current 0 in the first ;ranch+

CIRCUIT DIAGRA M :

PROCEDURE:

1+ Ma,e the connection accor(ing to the circuit (iagram

#+ Measure the value of current ;y ammeter

"+ 0nterchange the position of the ammeter an( the voltage source

&+ Now again measure the value of current

$+ Verify that 010# .


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OBSERVATION TABLE:

SRNO APLIED

VOLTAGE

*v+,-s.

I0*A.

I#*A.

ERROR

I02I#

RESULT : Reciprocity theorem has ;een verifie(

DISCUSS I ON: 0n the ;ilateral linear networ, the position of voltage source an( the ammeter cinterchange( +there will not ;e any change in their rea(ings+

PRECAUTIONS:

1+ .'0TC@ 4// the supply when not in use+

11+ Rea(ing shoul( ;e ta,en carefully+

1#+ %ll connections shoul( ;e tight an( correct+


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QUI ( /ANSWER:

Ques To what type of the c,t* the reciprocity theorem applica;le8A!s 3inear an( ;ilateral

Ques 'hat is transfer resistance in reciprocity theorem8A!s =B0 transfer resistance

Ques 0s reciprocity theorem applica;le to ac8A!s es

Ques 'hat are mutually transfera;le in the reciprocity theorem8A!s = an( 0 are mutually transfera;le

Ques 0s this theorem applica;le to the c,t having capacitor or in(uctor8A!sNo* it is applica;le to only resistive ac c,t+

Ques 'hat is the fre:uency of mains8A!s $ hero

Ques 'hen will the power e-tracte( from a c,t is ma-imum8A!s 'hen R3 is e:ual to the internal resistance of the c,t+


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Ques @ow is the ammeter connecte( in circuit8A!s 0n series

Ques To fin( the voltage (rop across a resistance* where shoul( the voltmeter ;e connecte(8A!s 0n parallel+


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E"PERIMENT NO 4

AIM: TO MEASURE T&E POWER DRAWN B% A SINGLE P&ASE AC CKT USING T&

VOLTMETERS

APPARA T US: V43TM=T=R* %MM=T=R* R@=4.T%T* V4NN=CT0N? 3=%D.

T&EOR%:

To measure the power in an in(uctive loa( three voltmeters are use( which recor(s the follovoltagesV1 recor(s the voltage across the resistance of ,nown valueV# recor(s the voltage across te in(uctorV" recor(s the voltage applie( to the c,t V# 0CosL powerconsumes ;y loa(

V1 V# CosL BRpower consume( ;y in(uctive loa(5V)

#2V0

#2V

#./#R

CIRCUIT DIAGRA M :

PROCEDURE :

1+ Connect the c,t as shown in fig#+ =nsure that the output voltage is not

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E+ Repeat the whole e-periment for the (ifferent values of the voltageG+ /in( the value of VB0 in all the casesH+ .witch off the power supply after use+


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OBSERVATION TABLE:

SNO V0 *VOLTS. V# *VOLTS. V) *VOLTS. I*A. P5*V) 2V0 -V0

*W.

RESULT :The power (rawn ;y single phase ac c,t using three voltmeter is7777++

DISCUSS I ON :The power consume( ;y the single phase ac c,t can ;e calculate( ;y the rea(inthree voltmeters+

PRECAUTIONS:

1E+ %ll connections shoul( ;e tight an( correct+1G+ .'0TC@ 4// the supply when not in use+1H+ Rea(ing shoul( ;e ta,en carefully+

QUI ( /ANSWER:

Ques+ 'hat is fara(ays first law8A!s+ 'hen magnetic flu- lin,e( with a c,t changes* an emf is in(uce(+

Ques.'hat is fara(ays secon( law8A!s+The magnitu(e of the in(uce( =M/ is e:ual to the rate of change of flu- lin,age

Ques.'hat is the (imension of 3C8A!s+0t has the unit of velocity

Ques.'hat is the power (rawn ;y a three phase ;alance( loa(8

A!s." V3 03 C4.Ques+Can a repulsion!in(uction motor ever run at super synchronous spee(8A!s+=.

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Ques+ Can a (c shunt motor run at heavy loa(s8A!s.%t heavy loa(s the internal (rop ;ecomes very large an( hence the terminal voltage are re(uca very low value an( finally resulting into run away+

Ques+ 'hat is %CA8A!s+%ir c,t ;rea,er

Ques.'hich electric motor is use( in ceiling fan8A!s+.ingle phase capacitor run in(uction motor

Ques.'hich motor is use in the refrigerator8A!s+.ingle phase capacitor start in(uction motor

Ques+ 0n which N0T. transformers are rate(8A!s+KV%

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E"PERIMENT NO 6

AIM: TO PER$ORM T&E DIRECT LOAD TEST ON T&E TRANS$ORMER AND PLOT

T&E CURVE BETWEEN E$$ICIENC% AND VOLTAGE

APPARA T US: %T4 TR%N./4RM=R* .0N?3= @%.= D4A3= '4ND TR%N./4RM

%MM=T=R* V43TM=T=R+T&EOR%:

The ac emf is applie( to the primary coil* the ac current in the primary coil gives rise to flu- chThe change of flu- in(uces emf in the secon(ary coil (ue to mutual in(uction

CIRCUIT DIAGRA M :

PROCEDURE:

1+ Connect the c,t as shown in fig+#+ Ta,e the rea(ings of 01 an( V1 for primary"+ Ta,e the rea(ings of of 0# an( V# for secon(ary&+ Calculate the efficiency of the transformer using the formula$+ =fficiency output powerBinput power+

OBSERVATION TABLE:

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SNO I0*A.

V0*v+,-s.

I#*A.

V#*v+,-s.

E$$ICIENC%5V# I# /

V0 I0

GRAP&: The efficiency increases with the increase in voltage an( ;ecomes ma-imum at a partivoltage an( after that it (ecreases+

RESULT :

The efficiency of the single!phase transformer comes out to ;e777777

DISCUSS I ON: Mutual in(uction is the ;asic principle in the transformer+ Direct loa( test is carriout to fin( out the efficiency of the transformer+

PRECAUTIONS :

1 %ll connections shoul( ;e tight an( correct+

# .'0TC@ 4// the supply when not in use+

" Rea(ing shoul( ;e ta,en carefully+

QUI(/ANSWER:

Ques 'hat is the effect on the fre:uency in the transformer8A!sNo change

Ques 'hat is the me(ium for the energy conversion from the primary to secon(ary in the transfor

A!s Ay the flu-

Ques 'hat is the main reason for the generation of harmonics in the transformer8A!s .aturation of the core+

Ques 'hy are the ferrite cores use( in the high fre:uency transformer8A!s @igh resistance

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Ques 'hat type of win(ing is use( in the "!phase shell type transformer8A!s .an(wich type

Ques 'hat is increase( in step up transformer8A!s Voltage

Ques 'hat is the effect on voltage in step (own transformer8

A!s Voltage is (ecrease(

Ques 'hat is the formula of efficiency8A!s 4utput energyBinput energy

Ques 'hat is the function of ;ushings in the transformer8A!s To ma,e the e-ternal connections

Ques 'hat is the principal of transformer8A!s Mutual in(uction+

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E"PERIMENT NO 7

AIM:TO STUD% $REQUENC% RESPONSE O$ SERIES R2L2C CIRCUIT AND DETERM

RESONANCE $REQUENC%

APPARA T US :CR4* %D04 /R=Q=NC ?=N=R%T4R*M3T0M=T=R %ND C4NN=CT3=%D.+

T&EOR% :in the series resonance circuit * the net reactanceOO3+OC.o impe(ence of the c,t is

>5R#2 5O3+OC 6#6

at the resonance fre:uency the capacitive reactance ;ecomes e:ual to the in(uctive reactance+O3 1OCw331Bw3C

f31B#PM3C

CIRCUIT DIAGRA M :

PROCEDURE :

1+ Ma,e the connection s shown in fig#+ /re:uency is given ;y au(io fre:uency generator"+ Change the fre:uency an( note the rea(ing carefully&+ %t certain fre:uency the voltage ;ecomes ma-imum after which the voltage (ecreases+ T

the resonance fre:uency$+ lot a graph ;etween fre:uency an( voltage+

OBSERVATION TABLE:

.+N4 /R=Q=NC 5K@

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RESULT : The resonance fre:uency is foun( to ;e77,@

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E"PERIMENT NO 8

AIM:TO STUD% $REQUENC% RESPONSE O$ A PARALLEL R2L2C CIRCUIT A

DETERMINE RESONANCE $REQUENC%

APPARA T US : CR4* %D04 /R=Q=NC ?=N=R%T4R* M3T0M=T=R %ND C4NN=CT3=%D.+

T&EOR%: for the parallel R!3!C c,t0C03 .in 303VB>*.in 3O3B>

VB>FO3 B>VBOC4r O3FOC>#

N4' O3w3* OC1BwC'3BwC># or 3BC>#

3BCR# 2 O #

fo1B#P F 1B3C+R#B3#

CIRCUIT DIAGRA M :

PROCEDURE :

E+ Ma,e the connection s shown in figG+ /re:uency is given ;y au(io fre:uency generatorH+ Change the fre:uency an( note the rea(ing carefullyI+ %t certain fre:uency the voltage ;ecomes minimum after which the voltage increases+ This

resonance fre:uency1+ lot a graph ;etween fre:uency an( voltage+

3

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OBSERVATION TABLE:

.R+N4 /R=Q=NC 5K@

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Ques 'hat is the effect of the in(uctance on the time constant in any in(uctive c,t8A!s Increases with increase in in(uctance an( (ecreases with (ecrease in R

Ques 'hat is the effect of (c flow on the (c8A!s Only at the time of on an( off

Ques Can all the laws of the (c ;e applie( to the ac c,t having resistance8A!s yes

Ques 'hat is the time constant of the capacitive c,t8A!s RC

Ques 'hat is the effect of length of iron path on in(uctanceS8A!s 0n(uctance varies inversely as the length of iron path+

Ques 0f two signals having same fre:uency have opposite phase* what is the phase angle;etween them8

A!s 1H3

Ques /or least power consumption what shoul( ;e the phase angle ;etween current an( voltage8A!s I3

Ques 'hat is magnifie( ;y the parallel R3C c,t8A!s current+

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E9eri e !- N+ 0;

RESULT: The (ifferent measuring instruments have ;een stu(ie(+

DISCUSS I ON: %mmeters are use( to measure the current ;ut the moving coil type ammeter ionly for %C+ 0n(uction type wattmeter is use( to measure the %C only* while the electro(ynamicwattmeter is use( for DC only+

PRECAUTIONS:

QUI(/ANSWER:

1 %ll connections shoul( ;e tight an( correct+

# .'0TC@ 4// the supply when not in use+

" Rea(ing shoul( ;e ta,en carefully+

Ques 'hat is the cheaper metho( of starting a "!phase in(uction moor8A!s Direct over loa( starting

Ques 'hen a (c motor pro(uces a ma- output power8A!s 'hen ;ac, emf is e:ual to half of the applie( voltage+

Ques 'hat is the use of wattmeter8A!s it is use( to measure the power consume( in a c,t+

Ques 'hat are the (ifferent types of the wattmeter8A!s Dynamometer* in(uction an( electrostatic

Ques 'hat is the use of integrating or the energy meter8A!s it is use( to measure the :uantity of electric energy supplie( to the to a c,t in a given time

Ques 'hat is a meggar8A!s These are the instruments which are use( to measure the insulation resistance relative to ea

Ques 'hat are the two types of the moving iron instruments8A!s %ttraction type

Repulsion type

Ques 'hat are the (ifferent types of the moving coil instruments8

A!s ermanent magnet typeDynamometer type

Ques 'hat are the sources of error with the (c in moving iron instruments8A!s =rror (ue to hysteresis

=rror (ue to stray fiel(

Ques 'hat are the errors with the ac in moving coil instruments8A ( h i

(291882886) et-lab-manual

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