BVoc programme in Automobile Auto Electricals & Electronics

U.O.No. 9483/2015/Admn Dated, Calicut University.P.O, 09.09.2015

Usha K

Deputy Registrar

File Ref.No.72742/GA - IV - J1/2014/Admn

UNIVERSITY OF CALICUT

Abstract

BVoc programme in Automobile Auto Electricals & Electronics- under Modified BVoc Regulations

2014 – Question Bank - implemented w.e.f 2014 admission onwards - Orders issued

G & A - IV - J

Read:-1) BVoc Regulations implemented as per U.O.No. 9809/2014/Admn Dtd 23.10.2014

2) Modified BVoc Regulaitons U.O.No. 2650/2015/Admn Dtd :17.03.2015

3) Syllabus implemented as per U.O.No. 4516/2015/Admn Dt 04.05.15

4) Minutes of the Combined meeting of all Chairmen of BOS & Principals of the

Colleges having BVoc Programmes

5) Remarks of the Dean, Faculty of Science 4.08.15

4) Orders of Vice Chancellor in the File on 29.08.15

ORDER

As per the paper read as (1) & (2) the Regulations for BVoc Programmes have been

implemented and modified. As per paper read as (3) the BVoc programme in Automobile Auto

Electricals & Electronics has been implemented.

As per the paper read as (4) the Question Bank of Automobile Auto Electricals & Electronics

have been approved. As per paper read as (5) the Dean Faculty of Science has recommeded to

approve minutes of the Combined meeting of Chairmen and Principals. Considering the urgency

the Vice Chancellor exercising the powers of the Academic Council has approved to implement the

Question Bank of BVoc in Automobile Auto Electricals & Electronics subject to the ratification of

Academic Council

Sanction has, therefore, been accorded for the implementation of the Question Bank of

the BVoc programme in Automobile Auto Electricals & Electronics, w.e.f 2014 Admissions.

Orders are issued accordingly.

Forwarded / By Order

Section Officer

To

Course No: 2.6 Course Code: SDC2AE04 (P)

Course Name: Automotive Electrical Laboratory I

Questions.

1. Find out the internal resistance of the given battery. 2. Calculate the reserve capacity of given battery by conducting specific gravity test. 3. Calculate the reserve capacity of the given battery using its standard notations. 4. Trouble shoots the given battery. 5. Trouble shoots the given alternator also check the charging rate noise of the alternator. 6. Diagnose the ignition system fault for the given engine. 7. Draw and implement conventional automobile lighting circuit layout. 8. Draw and implement conventional automobile trafficator, wiper circuit layout. 9. Find the unknown resistance value using Kelvins double bridge. 10. Find out the unknown inductance value using the standard given capacitors using

Maxwells capacitace Inductance Bridge. 11. Measure the capacitance value and dissipation factor using given Schering Bridge. 12. Find out percentage ratio error of given potential transformer and current transformer. 13. Calibrate the given RTD using given thermometer. 14. Calibrate the given Thermistor using given thermometer. 15. Calibrate the given Pressure transducer using given Barometer. 16. Calibrate the given Pressure transducer using given known weights.

FAROOK COLLEGE, KOZHIKODE

B VOC AUTOMOBILE AUTO ELECTRICAL AND ELECTRONICS

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SDC1AE02

Basic electrical engineering



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SDC1AE02 – BASIC ELECTRICAL ENGINEERING Course No: 1.5

Course Code: SDC1AE02

Course Name: Basic electrical engineering

Credits: 5

Hours: 75

COURSE OUTLINE

Unit I – FUNDAMENTALS OF DC CIRCUITS (18 hours)

Introduction to DC and AC circuits, Active and passive two terminal elements, Ohms law,

Voltage-Current relations for resistor, inductor, capacitor, Kirchhoff's laws, Mesh analysis,

Nodal analysis, Ideal sources –equivalent resistor, current division, voltage division.

Unit II – MAGNETIC CIRCUITS (18 hours)

Introduction to magnetic circuits, Problems involving simple magnetic circuits. Faraday’s

laws induced emfs and inductances, Definition of mmf, flux and reluctance, leakage flux,

fringing, magnetic materials and B-H relationship and eddy currents.

Unit III – AC CIRCUITS (18 hours)

Sinusoids, Generation of AC, Average and RMS values, Form and peak factors, concept of

phasor representation, J operator. Analysis of R-L, R-C, R-L-C circuits. Introduction to three

phase systems - types of connections, relationship between line and phase values.

Unit IV – ELECTRICAL MACHINES & MEASURING INSTRUMENTS (21 hours)

Working principle, construction and applications of DC machines and AC machines (1 -

phase transformers, 3-phase induction motors, single phase induction motors: split phase,

capacitor start and capacitor start & run motors, DC shunt generator). Basic principles and

classification of instruments -Moving coil and moving iron instruments, 3-phase squirrel cage

induction motor, DC series motor, slip ring induction motor.



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UNIT 1-FUNDAMENTALS OF DC CIRCUITS

MCQS

1) What is the frequency of a DC signal?

a)50 Hz

b)0 Hz

c)230 Hz

d)220 Hz

2) An ac voltage is represented by V=Vm Sin (100πt),what is the frequency of the signal?

a) 0 Hz

b) 100 Hz

c) 50 Hz

d) 100π

3) The sources of electrical energy in electric circuits are called --------------------- elements?

a) passive

b) active

c) independent

d) dependent

4) V=5 Sin (wt) is applied across an inductor L . What is the equation of instantaneous current

through the inductor?

a) 5/LW (Sin(wt-90))

b) 5/LW (Sin(wt+90))

c) 5/LW (cos(wt+90))

d) 5/LW (Sin(wt))

5) Which law defines the relationship between voltage applied and current passing through a

conductor?

a) Kirchhoff ‘s voltage law



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b) Ohm’s law

c) Faraday’s law

d) superposition theorem

6)Who is known as father of electricity?

a)Michael Faraday

b)Henrich Hertz

c)Ohm

d)Alessandro Volta

7)A material of permittivity ε is kept between two parallel plate of area A and d distance apart.

And a voltage V is applied .What is the value of charge stored between the plates?

a) ε0 ε2 a/d

b) ε0 ε d/a

c) (ε0 ε a/d)v

d) ε0 ε a/d

8)The property of a material which defines the ease of electrification is called --------------------?

a)Permittivity

b)Permeability

c)resistivity

d)Reluctivity

9)The SI unit of capacitanceis --------------?

a)Henry

b)Hertz

c)Farad

d)ampere turns



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10)Thealgebraic sum of current entering a junction in a circuit is -----------------------?

a)zero

b)one

c)finite

d)can not be determined

11)The algebraic sum of voltage drop in a closed circuit is equal to ----------------------?

a)zero

b)finite

c)the source voltage

d)one

12) Which analysis will you prefer for a parallel network?

a)mesh analysis

b)kirchoffs current law

c)kirchoffs voltage law

d)node analysis

13) How much power an ideal source can deliver to a load?

a)High amount

b)Zero

c)cant be determined

d)Infinite

14) The value of internal resistance for an ideal voltage source is ----------------------------?

a)any value b)Infinite c)one d) zero



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15) The source with high value of internal resistance is called -----------------------------?

a)voltage source

b)Current source

c)Dependent source

d)Independent source

16) If two resistances of value R are connected in parallel. What will be the equivalent

resistance value?

a)2R

b)R/2

c)R2/2

d)2R2

17) If length of a material halved and area of cross section is doubled .What happens to its

resistance?

a)1/4 times original value

b) 1/2 times original value

c) same as original value

d)Doubles

18) If three equal resistances are connected in series and a voltage of value V is applied. How

much percent of total voltage will appear across the single resistor?

a)33.33%

b)30%

c)35%

d)50%

19) If 10A current enters into a parallel network of 5Ω and 3 Ω resistances .What is the current

passing 3 Ω resistor?

a)3 A b)6.66 A c)3.33 A d)5 A



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20) The device which stores electric charge is -------------------------?

a) Battery

b)Inductor

c) Capacitor

d)generator

21)In a 3 node network the number of mesh equations and node equations are equal .What is the

number of branches in that network?

a)4

b)3

c)5

d)2

22)A transistor belongs to ----------------------- source?

a)independent current

b) dependent voltage

c) dependent current

d) independent voltage

23) What is consumer supply frequency in India?

a)60 Hz

b)50 Hz

c)230 Hz

d)100Hz

24)A parallel plate capacitor has capacitance of 50µF,in air and 110 µF when immersed in oil.

The dielectric constant of the oil is

a)0.45 b)0.55 c)1.1 d)2.2



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25)Equivalent resistance in parallel is always

a)sum of the resistances

b)difference of the resistances

c)lower than the smallest resistance value

d)sum of the resistances

26)Three resistances of 1Ω each are connected to form a triangle. The resistance between any

two corners will be

a)3Ω

b)3/2Ω

c)2/3Ω

d)1/3Ω

27)Minimum resistance obtained by combining five 1/5 resistances is

a)1/10

b)1/25

c)1/5

d)1/50

28)If the radius of a wire is constant and length is increased, its resistance become

a)double

b)half

c)one fourth

d)four times

29)The number of independent mesh equations needed to solve a circuit is

a)no.of branch-(no of junction-1) b)no of branch-1

c)no of junction-1 d)no of branch-no of junction



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30)The number of independent node equations needed to solve a circuit is

a)no. of branch-(no of junction-1)

b)no of branch-1

c)no of junction-1

d)no of branch-no of junction

31)A battery is an example of

a)active element

b)passive element

c)dependent source

d)insulator

32)A resistor is an example of

a)active element

b)passive element

c)dependent source

d)dependent source

33)Out of the following elements which is a dependent source

a)battery

b)generator

c)inductor

d)transistor

34)Out of the following elements which is an independent source

a)electric bulb b)generator

c)inductor d)transistor



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35)Which of the following elements obey ohms law

a)diode

b)transistor

c)copper conductor

d)L E D

36)Who is known as father of electricity

a)George simon Ohm

b)Alexandro volta

c)Henrich hertz

d)Michael Faraday

Two mark questions

37) State and explain Ohms law in electric circuits?

38) What is the expression for reactance offered by a capacitor towards power supply.

What happens if the frequency of the supply increases?

39) What is the expression for reactance offered by a capacitor towards power supply.

What happens if the frequency of the supply increases?

40) Differentiate between active and passive elements?

41) State and explain kirchhoff’s voltage law?

42) Find the equivalent resistance of the given network?



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43) Find the equivalent resistance of the given network?

44) Find the source current in the given network?

45) Calculate effective resistance between A and B?



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47) What do you mean by ideal voltage source?

48) What do you mean by ideal current source?

49) Find the current through 2Ω and 4Ω resistances in the given circuit?

50) Find the current through 3Ω and 10Ω resistors?



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51) State and explain kirchhoff’s current law?

52) A parallel plate air capacitor has capacity=2µF,If a metal block is introduced between the

plates to cover half the space, find the new capacitance?

53) Differentiate between independent and dependent sources?

54) With a suitable network explain voltage division rule in a series network?


56) Plot the voltage current characteristics for ideal voltage and current sources?

57) Explain why transistor is treated as a current source and battery as a voltage source?


59) Explain why parallel circuits are solved using nodal analysis?

60) Inductor by passes dc and offers maximum resistance to ac. justify?

61) Capacitor bypasses ac and offers maximum resistance to dc. Justify?



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Four mark questions

62) Derive voltage-current relationship for inductor and capacitor?

63) Determine the currents in the given network?

64) Find I1,I2,I3and,I4 in the given net work?

65)find the source current in the given network.



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66) Find the current and power dissipation in 5Ω resistor?

67) Determine power loss in 5Ω resistor?

68) Find V1 and V2 using KVL?

\



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69) Find V such that 100C charge is injected into 50V source in 1 minute in the circuit?

70) Find voltage needed across a-b terminals so that voltage drop across 10Ω resistance is 45 v

71) Find voltage needed across a-b terminals so that voltage drop across 10Ω resistance is 30 v



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72) Differentiate between active and passive elements? Give examples?

73) What is the use of a capacitor? Derive the expression for voltage current relation in a

capacitor?

74) Find equivalent resistance of the given network?

75) Find the current through each resistance in the given network?

76) Find voltage drop in each of the resistance in the given network?



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77) With graph and expression, explain ideal voltage and current source?

78) A resistor of 5Ω is connected in series with a parallel combination of 6Ω,3Ωand 2Ω. A 5V

source is connected across it. Find the supply current and current passing through each resistor?

79) Three resistors 10Ω.20Ω and 30Ω are connected in series across a 100V supply. Find the

voltage across each resistor?


81) Inductor bypasses dc and offer maximum resistance to ac. Capacitor bypasses ac and offer

maximum resistance to dc. justify?



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15 Mark questions

82) Using nodal analysis, find the current through each resistor in the circuit configuration?\

83) Find the battery currents using nodal analysis?



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84) Find the current through each resistor using nodal analysis?

85) What is the value of R such that power dissipated by each sources are equal to each other?

[The internal resistance of the battery is given as 1Ω]

86) What is the power loss in the 10Ω resistor in the network shown?Use mesh method?



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87) Determine node voltage and current through the resistors using mesh method?

88) Find V by mesh method such that the current through 5V sourceis 0



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89) Find current through each resistance using any of the circuit analysis methods?

90) Obtain the current through each of the sources and the respective power dissipation in the

network?



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91) In the figure, find V0,Also find current through a to b if the terminals a and b are shorted?

92) In the network given below calculate the mesh currents I1,I2,I3 by mesh analysis.Hence obtain

the node voltage V1 andV2 and also the voltage across 6Ω resistor?



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93) Using nodal analysis, find the current through each resistor in the circuit configuration?

94) In fig using node analysis, find the current in each resistors?



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UNIT II -MAGNETIC CIRCUITS

MCQ’S

1) What is the unit of magneto motive force?

a) Ampere turns

b) Webber

c) Webber/m2

d) No unit

2) The property of a material which allows the magnetic lines of force to pass through the

material is called -------------------------------?

a) Permeability

b) permittivity

c) Reluctivity

d) coercivity

3) The inverse of reluctivity of a material is called ----------------------?

a) Permeability

b)permittivity

c)Reluctivity

d)coercivity

4) What will happen if we rotate a conductor in a magnetic field?

a) Induce emf in the conductor

b) A current will pass through the conductor

c) conductor will continue its rotation

d) none of the above

5) The unit of magnetic lines of force is ------------------------------?

a) webber b) Tesla c) Webber/m2 d) No unit



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6) The property of a material which opposes the flow of magnetic flux through the material is

called----------?

a) reluctance

b) reluctivity

c) coercivity

d) retentivity

7) The phenomenon of reduction of effective area of magnetic flux lines when passing to low

permeability medium is called -------------------?

a) Hall effect

b) de-magnetization

c) fringing

d) fluxation

8) Hysterisis curve is the graph drawn between ----------along X axis and ---------- along Y axis?

a) H ,B

b) B,H

c) B,I

d) B,Ampereturns

9) If we double the length and area of a ferromagnetic material with an applied mmf what

happens to the flux passing through it ?

a) Increases to 4 times

b) remains same

c) Decreases to 1/4 times

d) 2 times

10) The direction of induced emf in a conductor is specified by ---------- law?

a) Flemings right hand rule b) Faraday,s law

c) Flemings left hand rule d) Lenz’s law



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11) What is leakage factor?

`a) Total flux/leakage flux

b) leakage flux/ Total flux

c) magnetic flux density/mmf

d) mmf/ magnetic flux density

12) Give the expression for magnitude of induced emf?

a) e=LI

b) e= Ld/dt(I)

c) e=NI

d)e=N d/dt(I)

13) What is the value of leakage factor in practical magnetic circuits?

a)1.8

b)1

c)1.2

d)2

14) Magneto motive force in a coil is

a) number of turns X current passing through it

b) number of turnsX current passing through it2

c) 2(number of turnsX current passing through it)

d) independent of current

15) Magnetic flux is

a) imaginary lines of force from north pole to south pole

b) imaginary lines of force from south pole to north pole

c) lines of force from north pole to south pole

d) lines of force from south pole to north pole



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16) Expression for reluctance of a magnetic circuit is

a) S=L/(µA)

b) S=LµA

c) S=Lµ/A

d) S=L2/(µA)

17) Coercivity in B-H curve is

a) minimum value of magnetizing force when magnetic field intensity is zero

b)value of magnetizing force when magnetic field intensity is zero

c) minimum value of magnetic field intensity when magnetizing force is zero

d)value of magnetic field intensity when magnetizing force is zero

18) Retentivity in B-H curve is


b) value of magnetizing force when magnetic field intensity is zero


d) value of magnetic field intensity when magnetizing force is zero

19) The term residual magnetism means


b) value of magnetizing force when magnetic field intensity is zero


d) value of magnetic field intensity when magnetizing force is zero

20) The area of B-H curve increases, the permeability

a) increases

b) decreases

c) independent

d) increases upto acertain value and then decreases



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21) If the length of magnetic path of a ferromagnetic material is doubled and area of cross

section halved,

the total flux will becomes

a)4 times

b)2 times

c)1/4 times

d)remains constant

22) If the length of magnetic path of a ferromagnetic material is doubled and area of cross

section halved,

the total reluctance of the magnetic path will becomes

a) 4 times

b) 2 times

c) 1/4 times

d) remains constant

23)MMF=

a) length/(permeability X area of cross section)

b) magnetic flux x reluctance

c) number of turns/current

d) magnetic flux / reluctance



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2mark

24. Define mmf magnetic flux and reluctance

25 . Explain magnetic fringing

26. Explain the classification of magnetic materials based on their permeability?

27 . What do you meant by magnetic hysteresis?

28 .Why transformer cores are laminated?

29.What do you meant by leakage factor in a magnetic circuit?What is its normal value?

30 state faradays law of electromagnetic induction

31What do you meant by eddy current?

32 Explain the term coercivity?

33 Explain the term retentivity?

34 Explain the term residual magnetism?

35 What is the significance of residual magnetism in dc shunt generator?

36 What do you meant by a ferromagnetic material?

37 What do you meant by Paramagnetic material?

38 What do you meant by a diamagnetic material?

39 Differentiate between permeability and permittivity?

40 Ferromagnetic material is used as magnetic material in electrical equipments. Why?

41 Calculate the number of turns needed for a 5A electromagnet to have mmf=25 AT



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4mark

42 Explain faradays law of electromagnetic induction

43 Differentiate Ferromagnetic, paramagnetic and diamagnetic materials?

44 Explain hysteresis?

45 Explain why transformer cores are laminated?

46 With diagram explain magnetic fringing?

15mark

47. A rectangular iron core shown in fig has mean length of magnetic circuit of 100 cm,cross

sectional area of 2cmx2cm and relative permeability of 1400 and airgap of 5mm cut in it.The

three coils carried by the core have number of turns Na=335,Nb=600 and Nc=600.The respective

currents are 1.6A,4Aand 3A.The directions of the currents are as shown.Find the flux in the

airgap?



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48 A cast steel of magnetic structure made of a bar of section 2cmx2cm is shown in fig.

Determine the current that the 500 turn magnetizing coil on the left limb should carry so that a

flux of 2mwb is produced in the right limb?

49. With neat diagram explain B-H curve for a ferromagnetic material?Also explain the terms

coercivity retentivity and residual magnetism



three coils carried by the core have number of turns Na=670,Nb=900 and Nc=200.The respective

currents are 3.6A,4.2Aand 3.8A.The directions of the currents are as shown.Find the flux in the

airgap?



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51 A cast steel of magnetic structure made of a bar of section 2cmx2cm is shown in fig.





three coils carried by the core have number of turns Na=1670,Nb=3900 and Nc=1200.The

respective currents are 0.6A,4.2Aand 7.8A.The directions of the currents are as shown.Find the

flux in the airgap?



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53. A cast steel of magnetic structure made of a bar of section 1cmx1cm is shown in fig.





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UNIT III-AC CIRCUITS MCQS

1) What is form factor?

a)Peak value/rms value

b) average value/ rms value

c) rms value /Peak value

d)rms value/average value

2) Define peak factor?

a)Peak value/rms value

b) average value/ rms value

c) rms value /Peak value

d)rms value/average value

3) J operator rotates a vector by ---------------- degree?

a) 90

b) 120

c)180

d) 45

4) In a star connected 3 phase ac circuit what is the relationship between line and phase voltages?

a) √3VL=VPH

b) VL=VPH

c)VL=√3VPH

d) VL=VPH

5) In a delta connected 3 phase ac circuit what is the relationship between line and phase

currents?

a) √3IL=IPH b) IL=IPH c)IL=IPH d) IL=IPH



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6) In a delta connected 3 phase ac circuit what is the relationship between line and phase

voltages?

a) √3VL=VPH

b) VL=VPH

c)VL=√3VPH

d) VL=VPH

7) In a star connected 3 phase ac circuit what is the relationship between line and phase currents?

a) √3IL=IPH

b) IL=IPH

c)IL=IPH

d) IL=IPH

8) The average value of ac voltage wave form of maximum value Vm is ---------------?

a)Vm/√2

b)2 Vm/π

c) Vm/π

d) Vm/2

9) The rms value of ac voltage waveform of maximum value Vm is ---------------------?

a)Vm/√2

b)2 Vm/π

c) Vm/π

d) Vm/2

10) The phase difference between voltage and current in an RC circuit having reactance Xc and

resistance R is -----------------?

a)Tan-1(xc/2R) b) Tan-1(R/ xc) c) Tan-1(2xc/R) d)None of these



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11) What is the expression for resonant frequency in RLC series circuit?

a)1/(2LC)

b)1/(6.28LC)

c)1/LC

d)L/C

12) A Capacitor is a perfect insulator for

a)dc

b)ac

c)dc as well as ac

d)none of the above

13) An inductor is a perfect insulator for

a)dc

b)ac

c)dc as well as ac

d)none of the above

14) The instrument which work on the principle of mutual induction is

a)galvanometer

b)ammeter

c)potentiometer

d)transformer

15) A capacitor allows

a)dc to pass but blocks ac

b)ac to pass but blocks dc

c)both ac and dc

d)none of these



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16) In an ac circuit containing capacitance only,the current

a) lags behind the voltage by 90

b) leads the voltage by 90

c) in phase with the voltage

d) none of these

17) The voltage of the ac mains is represented by E=200√2sin 628t volts, where t is in seconds.

The frequency of ac is

a) 100Hz

b) 314Hz

c) 50Hz

d) none of these

18) The peak output voltage of a generator giving rms value=100V is

a) 100/√2

b) 140

c) 173Hz

d) 50√2

19) The average value of the alternating current for complete cycle is

a) zero

b) I/√2

c) I/2

d) Irms

20) In an ac circuit containing inductance only,the current

a) lags behind the voltage by 90 b) leads the voltage by 90

c) in phase with the voltage d) none of these



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21)In an ac circuit containing inductance and resistance ,the current

a)lags the voltage

b) leads the voltage

c)in phase with the voltage

d) depends on the value of L and C

22) In an ac circuit containing capacitance and resistance ,the current

a) lags the voltage


c) in phase with the voltage

d) depends on the value of R and C

23) In an ac circuit containing capacitance ,inductance and resistance ,the current

a) lags the voltage


c)in phase with the voltage

d)depends on the value of R,L and C

24) The current in the R L C circuit will be maximum at

a) above resonance frequency

b) below resonance frequency

c) resonance frequency

d) Any frequency

25) The impedance in the R L C circuit will be minimum at

a) above resonance frequency

b) below resonance frequency

c) resonance frequency

d) Any frequency



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2 mark questions

26) Find the RMS value of an ac waveform having amplitude Vm?

27) Define form factor and peak factor?

28) Name the 2 basic connections of 3 phase and write down their voltage current relationships?

29) What are the advantages of 3phase system?

30) Write down the voltage current relationship for R-L and R-C series circuit?

31) Explain resonance in an ac series circuit?

32) In an R-L series circuit find the equation for instantaneous current passing through the circuit

if the resistance value is 1Ω , inductance value 1H and an ac waveform of frequency 50Hz is

applied across it?

33) Explain the principle behind generation of alternating current?

34)Calculate the resonant frequency for a series LCR circuit having

inductance=5H,C=500µF,R=10Ω

35) A series LCR circuit connected to a variable frequency 220V source has L=4H,C=25µF and

R=30Ω.Determine the source frequency which drives the circuit in resonance and the amplitude

of the current at resonating frequency?

36)For a 230V,50 Hz sine wave, find out the instantaneous voltage at 1ms after the positive

maximum value?

37)Add two voltages 50 < 30and 30 < -45 and show the result in polar form?

38)Define :(a) Time period (b) Amplitude

39)Define:(a)Frequency (b) Phase difference

40)A capacitor allows ac to pass through it and block dc. why?

41)An inductor allows dc to pass through it and block ac. why?

42)How electrical oscillation is produced in ac circuit?

43)Explain resonance in RLC series circuit?



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4 mark questions

44) In a series R L circuit ,R=20Ω while L=60 mH, The input current lags the supply voltage by

60.Obtain the value of applied frequency?

45) Find the time required for an alternating current to change its value from zero to the peak

value?

46)An inductance of 2H,A capacitance of 18µF,and a resistance of 10KΩ are connected to an ac

source of 20V with adjustable frequency. a)What frequency should be chosen to maximize the

current in the circuit)What is the value of this maximum current?

47) Derive the voltage- current relationship for an inductor?

48) Derive the voltage- current relationship for an capacitor?

49) Derive the RMS value of a sine wave having maximum amplitude=Vm

50) Calculate average value of an ac sine wave over half cycle?

51)An alternating current is given by i=14.14 sin 377t.

Find a)RMS value of current b) frequency c)average value of current d)Form factor

52)A series R-L circuit takes 160 watts of energy at 0.8 power factor lagging from 100V,50 Hz

supply. Determine the values of R and L?

53)A resistor of 50Ω and a capacitor of 100µF are connected in series across a 100V,50Hz

supply.Find the impedance, current, power factor and voltage across the resistor?

54)A 220V,100 Hz ac source supplies a series L C R circuit with a capacitor and a coil.If the coil

has 50mΩ resistance and 5mH inductance, find at resonant frequency, what is the value of

capacitance?

55)A 5µF is connected in series with a coil having inductance of 50mH.Determine the frequency

of resonance if the resistance of the coil of a 50V source operating at resonant frequency causes a

circuit current of 10ma.

56) In a series R L circuit ,R=10Ω while L=350 mH, The input current lags the supply voltage by

30.Obtain the value of applied frequency?

57) Derive the voltage- current relationship for an R-L series circuit?

58) Derive the voltage- current relationship for an R-C series circuit?



Page | 42

59)A 50µF capacitor,when connected in series with a coil having 40Ω resistance,resonates at

1000Hz.Find the inductance of the coil?Also obtain the circuit current if the applied voltage is

100V

15 mark questions

60)a)A RL series circuit draws a current of 1A when connected across a 10V,50 Hz ac supply.If

the resistance is 5Ω,find the inductance of the coil?.What is its power factor? ---------(8)

b)In a series R-L circuit, the inductance being 20mH,the impedance is 17.85Ω.The angle of lag

of the input current from applied voltage is 63.5,find the values of angular frequency and

resistance of the circuit? ---------(7)

61)a)In a series R L C circuit, an ac voltage of 120 < 0V is applied at a frequency of 50Hz. The

input current leads the voltage by 63.5.Find the value of R IF L=25mH and C=50µF.What are

the voltage drops across L and C?-----------------(8)

b)A series circuit has R=4Ω and L=0.01H.Find the impedance at 100Hz and 500Hz? ---------(7)

62)a)An alternating voltage of 100V and 50Hz is applied across a series circuit having

inductance of 5H,Aresistance of 100Ω and a variable capacitance. At what value of capacitance

will the current in the circuit be inphase with applied voltage ?Calculate current in this

condition.What will be the potential difference across resistance, inductance and capacitance? ---

------(8)

b)In an ac circuit,an inductance coil of resistance 50Ω,at 50Hz supply has a voltage leading the

current by 30.Find the inductance of the coil? ---------(7)

63)Derive using phasor diagram,the relationship between line voltage,phase voltage,line current

and phasecurrent in a balanced 3phase supply?

64)a)A star connected load has impedence of (3+j4)Ω in each phase and is connected across

balanced 3 phase delta connected alternator having line voltage of 120 V.Obtain the line current

of both load and generator? ---------(8)



Page | 43

b)In fig find the line currents provided the supply is balanced 100V,50Hz 3phase supply? ------

(7)

65) a)A star connected load has impedence of (6+j2)Ω in each phase and is connected across

balanced 3 phase delta connected alternator having line voltage of 230 V. Obtain the line current

of both load and generator?-----------(10mark)

b)explain the basic features of star and delta connection.--------(5mark)



Page | 44

UNIT IV-ELECTRICAL MACHINES & MEASURING

INSTRUMENTS

MCQS

1)An ac generator

a)creates electrical energy

b)creates mechanical energy

c)convertsmechanical energy into electrical energy

d)Converts electrical energy into mechanical energy

2)In a transformer of turns ratio=2,the input voltage is 200V.The output voltage will be

a)100V

b)600V

c)400V

d)800V

3)In a Step down transformer ,the number of turns in

a)primary is less

b)secondary is less

c)primary and secondary are equal

d)secondary is infinite

4)AC measuring instruments measure

a)peak value

b)rms value

c)average value

d)none of the above



Page | 45

5)A transformer transforms

(a)frequency

(b)voltage

(c)current

(d)voltage and current

6)Which of the following is not the basic element of a transformer

(a)core

(b)primary winding

(c)secondary winding

(d)mutual flux

7)Transformer cores are laminated inorder to

(a)simplify construction

(b)minimize eddy current lose

(c)eliminate magnetic hysteresis

(d)increase the voltage at secondary

8)A transformer having 1000 primary turns is connected to 250 V ac supply.For a secondary

voltage of 400 V,the number of secondary turnsshould be

(a)1600

(b)250

(c)400

(d)1250

9)A step up transformer increases

(a)voltage (b)power

(c)current (d)frequency



Page | 46

10)In relation to a transformer ,the ratio 20:1 indicates that

a)20 turns on primary 1 turn on secondary

b)primary voltage = 1/20(secondary voltage)

c)primary current=1/20(secondary current)s

d)For every 20 turn on primary there is1 turn on secondary

11) a galvanometer can be converted into an ammeter by connecting

a)low resistance in series

b)High resistance in parallel

c) low resistance in parallel

d)high resistance in series

12) A galvanometer can be converted into a voltmeter by connecting

a)low resistance in series

b)High resistance in parallel

c) low resistance in parallel

d)high resistance in series

13)brushes are used in generator for

a) protection of bearing

b) taking generator voltage into external circuit

c)converting ac to dc

d)For the protection against mechanical damage

14)Commutators are used in generator for

a) protection of bearing

b) taking generator voltage into external circuit

c)converting ac to dc



Page | 47

d)For the protection against mechanical damage

15)The deflection of moving iron instrument is

a)Proportional to current

b) Proportional to square of current

c)Independent of current

d) ) Proportional to square rout of current

16) The deflection of moving coil instrument is

a) Proportional to square rout of current

b) Proportional to square of current

c)Independent of current

d) ) Proportional to current

17) Moving coil instrument works on

a) Heating effect of current

b) magnetic effect of current

c) Induction effect of current

d) none of these

18)Attraction type and repulsion type instruments come under

a)Moving iron instrument

b)Moving coil instrument

c)electromagnetic instrument

d)electrodynamic instrument

19)The scale of the moving iron instrument is

a)logarithmic

b)uniform

c)non uniform



Page | 48

d)based on the quantity to be measured

20) The scale of the moving coil instrument is

a)logarithmic

b)uniform

c)non uniform

d)based on the quantity to be measured

21) Which type of motor is used in an electric fan?

a)DC series motor

b)DC shunt motor

c)Induction motor

d)AC series motor

22) The capacitor used in an electric fan is

a) Air capacitor

b) Paper capacitor

c) Electrolytic type

d) Mica capacitor

23) A self excited dc shunt generator works initially due to its

a) coercive force

b) Retentivity

c) permanent magnets

d) residual magnetism

24) Commutator used in dc motor is

a)electromagnetic

b)Split ring

c)commutator ring



Page | 49

d)slip ring

25) The speedometer is an example for

a)Electromagnetic instrument

b)electrodynamometer instrument

c)Moving coil instrument

d)Moving iron instrument

2mark questions

26) Why a single phase induction motor is not self starting?

27) What are the classifications of dc generator?

28) Explain the working principle of a transformer?

29) Why 3 phase induction motor is self starting?

30) What is the need of capacitor in a single phase induction motor?

31) Why transformer cores are laminated?

32) What is the use of a capacitor in single phase induction motor?

33) Explain Flemings left hand rule?

34) There is no need of brushes in an induction motor.why?

35) If there is no back emf in a dc motor what will happen?

4mark questions

36) What is the significance of back emf in a dc motor?

37) Explain any two classification of measuring instruments?

38) Explain the working principle of a transformer?

39) A 25 KVA transformer has 500 turns in the primary and 50 turns in the secondary. Primary

is connected to 3000 V,50Hz supply.Find the primary and secondary currents.Also find

secondary emf?

40) A 50 KVA transformer has 300 turns in the primary and 120 turns in the secondary. Primary

is connected to 1000 V,50Hz supply.Find the primary and secondary currents.Also find

secondary emf?



Page | 50

41) A 100 KVA transformer has 200 turns in the primary and 120 turns in the secondary.

Primary is connected to 3500 V,50Hz supply.Find the primary and secondary currents.Also find

secondary emf?

42) Explain the advantages and disadvantages of moving iron instruments?

43) Explain the advantages and disadvantages of moving coil instruments?

44) How a galvanometer can be converted into ammeter?

45) How a galvanometer can be converted into voltmeter?

46) With symbolic diagram,explain the working of a self excited dc shunt generator?

47) Explain the working principle of a dc motor?

48) Differentiate between a motor and a generator?

15 mark questions

49) With phasor diagram explain the working principle of a 3 phase induction motor?

50) a)A short shunt compound generator delivers a load current of 30A at 220V and has

armature, series field and shunt field resistances of 0.05Ω,0.30Ω and 200Ω

respectively.Calculate the induced emf and armature current?..........(9)

b) Explain the classification of dc generators?...................(6)

51) a)Explain the conversion of a moving coil galvanometer into ammeter and voltmeter?(8)

b) A Shunt generator delivers 450A at 230V and the resistance of shuntfield and armature are

50Ω and 0.03Ω respectively.Calculate the generated emf? ---------(7)

52)a)A long shunt compound generator delivers a load current of 50A at 500V and has armature

series field and shunt field resistances of 0.05Ω,0.03Ω and 250Ω respectively.Calculate

generated voltage and armature current?Allow 1V per brush for contact drop? ---------(8)

b) Explain the construction and working of a dc motor? ---------(7)

53)a)A 220 V dc machine has an armature resistance of 0.5Ω,If the armature current is 20A,at

maximum load, find the induced emf when the machine acts as a 1)generator 2)Motor---------(8)

b)With diagram, explain the construction and theory of permanent magnet moving coil

instrument. ---------(7)



Page | 51

Course No: 1.7 Course Code: SDC1AE04 (P)

Course Name: Electrical Engineering Practice

Questions:

1. Draw residential wiring circuit using energy meter fuses switches indicators and lamps. And also find the energy consumption in KwHr.

2. Design and implement fluorescent lamp wiring circuit. 3. Design and implement Stair case wiring circuit. 4. Design and implement godown wiring circuit. 5. Measure the voltage current and power for an ac power supply and also find the power

factor in given RLC series circuit. 6. Trouble shoots the given electrical equipment. 7. Assemble a centre tapped transformer using the given copper winding and iron core for a

turn ratio of two and also very the results. 8. Calculate the self inductance, mutual inductance and coefficient of coupling for the given

transformer. 9. Plot the load current vs. load voltage characteristics of a dc shunt generator. 10. Plot the load efficiency vs. load voltage characteristics of a dc shunt generator. 11. Plot the load current vs. load voltage characteristics of a dc series motor. 12. Plot the load efficiency vs. load voltage characteristics of a dc series motor. 13. Calibrate the given single phase energy meter at 0.5 pf. 14. Calibrate the given single phase energy meter at 0.75 pf.


Page | 1

SDCA1E01

ELECTRONICS (Analog)

B.Voc AUTOMOBILE – AUTO ELECTRICAL & ELECTRONICS


COURSE OUTLINE Unit I (8 Hours) Preliminaries of rectification, Bridge rectifier, Efficiency, Nature of rectified output, ripple Factor, different types of filter circuits, voltage multipliers, Zener diode voltage stabilization Unit II (15 Hours) Page | 2Different transistor amplifier configurations:- C-B, C-E, C-C, their characteristics, amplification factors, their relationships, Load line Analysis, Expressions for voltage gain, current gain and power gain of C.E amplifier, cut-off and saturation points, Transistor biasing, Different types of biasing - Base resistor, collector feedback resistor-voltage divider bias method, single stage transistor amplifier circuit, load line analysis, DC and AC equivalent circuits. R.C coupled amplifier- frequency response, and gain in decibels, Unit III (13 Hours) Basic principles of feedback, negative feedback and its advantages, positive feedback circuits Oscillatory Circuits-LC, RC oscillators, tuned collector oscillator, Hartley, Colpitt’s, phase shift oscillators - Expressions for their frequency. Unit IV (10Hours) Transmission and reception of radio waves, types of modulation, AM, FM their comparison advantages, demodulation, straight receiver- pulse code modulation (qualitative idea only) Unit V (14 Hours) Basic ideas of UJT, FET, MOSFET, OP-amp-basic operations, Application, inverting, Non inverting, summing amplifiers, Differentiator- integrator



Unit I MCQ’S (One mark questions)

1. When forward bias is applied to a junction diode it. (a)Increase the potential barrier (b) Decrease the potential barrier (c) Reduce the majority-carrier current to zero (d) Reduce the minority-carrier current to zero

Page | 3

2. In a power supply diagram, which block indicates a smoother dc output (a) filter (b) transformer (c) rectifier (d) regulator.

3. PIV of a non conducting diode in a centre tapped rectifier will be… (a)Vm (b) 2Vm (c) 0 (d) None of these

4. How many diodes are required for a Full wave rectifier? (a) 3 (b) 2 (c) 1 (d) 0

5. How many diodes are required for a half wave rectifier?

(a)3 (b) 2 (c) 1 (d) 0

6. rms value of house hold ac supply India is (a)230 V (b) 50Hz (c) 110V (d) 60 Hz

7. A Zener diode (a)Has a high forward-voltage rating (b) Has a sharp breakdown at low reverse voltage (c) Is useful as an Amplifier (d) Has a negative resistance

8. Among the following semiconductor material is. (a)Copper (b) Silicon (c) Silver (d) Mercury

9. Among the following conductor material is. (a)Quarts (b) Germanium (c) Bakelite (d) Silver.

10. Which one is having negative thermal coefficient of resistance? (a)Quarts (b) Germanium (c) Bakelite (d) Silver.

11. Which one is having higher value of resistance? (a)Quarts (b) Procelain (c) Bakelite (d) Silver.

12. Which one is having lesser value of resistance? (a)Quarts (b) Procelain (c) Bakelite (d) Silver.

13. Which one is having lesser value of resistance? (a)Quarts (b) Procelain (c) Bakelite (d) Silver.

14. Which one is having low value of resistance? (a)Aluminium (b) Procelain (c) Bakelite (d)Hard Rubber

15. Among the following which one is not Penta-valent impurity atom? (a) P (b) B (c) Al (d) Ga

16. Among the following which one is not Tri-valent impurity atom? (a)P (b) As (c) Sb (d) Ga

17. What will be the energy gap for conductor? (a)5eV (b)1eV (c) zero(d)7eV



18. What will be the energy gap for Insulator? (a)5eV (b)1eV (c) zero(d)7eV

19. What will be the energy gap for semiconductor? (a)5eV (b)1eV (c) zero(d)7Ev

20. The diode---- (A) Is the simplest of semiconductor devices (b) has characteristics that closely match those of a simple switch (c) is a two terminal device (d) All the above

Page | 4

2mark questions

1. Explain forbidden energy gap. 2. Define conduction band. 3. Explain doping and classify them. Draw current flow diagram of a rectifier. 4. Explain the term ripple factor. 5. What you mean by Peak Inverse Voltage of a diode? 6. Draw the circuit diagram for centre tap full wave rectifier. 7. Explain the term efficiency in rectification. 8. Insulators have very high forbidden energy gap explain? 9. How can we find ripple factor for a rectifier? 10. Is it a transformer is required to construct a half wave rectifier explain? 11. Note down the ripple factor of various rectifier. 12. Note down the efficiencies of various filters. 13. Explain why the Pi-Filter is used widely. 14. Explain the effect of temperature in extrinsic and intrinsic semiconductor. 15. Why the capacitor filter called so? 16. Explain the nature of output of different rectifiers.



4mark questions

1. Explain energy band in solids and classify solid according to their Fermi level energy gap.

2. Explain the formation of the electron hole pair in N type and P type semiconductor. Page | 5 3. Explain forbidden energy gap by drawing Energy band diagram.

4. Explain extrinsic semi conductor with diagram. 5. Explain junction theory briefly. 6. Explain VI –characteristics of a PN junction diode. 7. Classify rectifier and explain briefly. 8. Explain series inductor filter. 9. Explain LC –Filter. 10. Explain Pi filter. 11. Why bridge rectifier is preferred over centre tap rectifier. 12. What are the general applications of a Zener diode 13. Explain the performance of a full wave rectifier. 14. Explain the process of Zener diode voltage stabilization. 15. Give the typical values of a few Zener diodes that are available. 16. Which filter circuit gives better dc outputs explain? 17. How does the performance of capacitor input filter improves when RC time constant is

increased? 18. Explain how a rectifier works? 19. Derive the expression to find the efficiency and ripple factor for a half wave rectifier. 20. Derive the expression to find the efficiency and ripple factor for full wave rectifier.

15Mark questions

21. Explain how rectifier converts ac in to dc also explain types of rectifiers in detail. 22. Explain the working of a rectifier, classify them and also derive an expression for

efficiency and ripple factor. 23. (a)Classify and explain filters in detail.-------8mark

(b)Explain zener diode stabilization ----------7mark



Unit II

MCQ’S (One mark questions)

1. Which biasing circuit is most extensively used? (a) Common base (b) Common Emitter (c) Common collector (d) None Page | 6

2. Transistor was invented in? (b) 1948 (b) 1928 (c) 1938 (d) 1945

3. The Q-Point in a voltage amplifier is selected in the middle of the active region because (a) It gives a distortion less output (b) The operating point then becomes very stable

(c)The circuit then requires less number of resistors (d) It requires a small DC voltage.

4. Very thin and lightly doped region in transistor is? (a)Emitter (b) Base (c) Collector (d) None

5. The potential divider method of biasing is used in amplifiers to (a)Limit the input AC signal going to the base (b) Make the operating point almost independent of transistor characteristics (c) Reduce the base current (d) None of these

6. For a silicon transistor the value of VBE will be (a)0.7 (b) 0.8 (c) 0.5 (d) 0.3

7. The most popular biasing circuit is .. (a)Simplest bias circuit (b) fixed bias circuit (c) Voltage divider bias circuit (d) None of these

8. Select the odd one (a)Diode (b) BJT (c) FET (d) MOS FET

9. In a PNP transistor with normal bias (a)Only holes cross the collector junction (b) Only majority carrier cross the collector junction (c) Collector junction has a low resistance (d) The emitter junction is forward biased and the collector base junction reverse biased.

10. In a transistor with normal bias the emitter junction (a)Has high resistance (b) Has a low resistance (c) Is reverse biased (d) None of these

11. For a transistor action (a)The collector base junction must be forward biased (b) the base region must be very narrow (c) The base region must be N- type material (d) None of these

12. The main current crossing the collector junction in a normally biased NPN transitor is (a)diffusion current (b) drift current (c) hole current(d) Equal to the base current

13. The current ICBO flows in (a)The emitter, base and collector leads (b) The emitter and base leads (c) The emitter and collector leads (d)The collector and the base leads



14. A small increase in the collector reverse bias will cause

(a)A large increase in emitter current (b) a large increase in collector current (c) Very small change in collector reverse saturation current (d) None of these

15. Compared to CB amplifier, CE amplifier has (a)Lower input resistance (b)Higher output resistance (c) Lower current amplification (d) Higher current amplification

Page | 7

16. The input and output signal of a common emitter amplifier are (a)always equal (b)out of phase (c) always negative(d)in phase

17. A transistor is said to be in quiescent state when (a)No signal is applied to input (b)It is unbiased (c) No currents are flowing d) None of these

18. Select the current gain factor of CB transistor configuration among the following (a)100 (b)200 (c) 0.5(d)0.95

19. Among the following which one is the most extensively used transistor configuration?

(a)Common base (b) common emitter (c) common collector(d) none of these

20. Odd one out (a) Q-point (b) Quiescent condition (c) Operating point (d) Optimum power

2mark questions

1. Why we bias a transistor? 2. Name the different biasing circuits. 3. Draw the structure of NPN, PNP transistors with their symbols. 4. Draw the schematic diagram for different Transistor configuration. 5. Dc current gain of transistor in CE configuration is 100. Find dc current gain in CB

configuration. 6. Why CE configuration is most extensively used? 7. In a certain transistor emitter current of 1mA produces a change in collector current of

0.99 mA. Determine the current gain of the transistor. 8. What you mean by operating Point? 9. Draw the simplest biasing circuit. 10. Explain the term diffusion current? 11. Explain the term DC Alpha? 12. What do you mean by collector leakage current? 13. Note the saturation region in a common output characteristic curve in CE configuration? 14. Draw an NPN transistor connected in common collector configuration. 15. Explain why an ordinary junction transistor is called bipolar? 16. What are the input and output terminals in CE configurations? 17. Define all the important parameters of BJT?



4mark questions

1. Explain Junction theory. 2. Explain the quiescent condition of a transistor? 3. Explain the Q-point condition of a transistor? 4. For a certain transistor common base current gain is 0.98 and emitter current is

2mA.Calculate the values of collector current and base current Page | 8

5. The collector current is 2.9mA. If the base current is 100µA, calculate CB current gain factor?

6. Explain relationship between different current in transistor. 7. A certain transistor is having alpha dc of 0.98 and collector leakage current 1µ. Calculate

the base collector and base currents. When its emitter current is 1mA. 8. When Emitter current of a transistor is changed by 1 mA, its collector current changes by

0.995mA Calculate (a) Its CB current gain α (b) Its CE current gain β. 9. Draw and explain fixed biasing circuit. 10. Find the Q point in Collector to Base Bias circuit if the resistor used is 500, 500000 ohms

with a gain of 100 11. Establish a relationship between different transistor currents by drawing the electron flow

diagram? 12. Explain the working of a transistor? 13. Draw and explain the circuit arrangement for PNP transistor in CB configuration? 14. Draw and explain the circuit arrangement for NPN transistor in CB configuration? 15. Draw and explain the circuit arrangement for PNP transistor in CE configuration? 16. Draw and explain the circuit arrangement for NPN transistor in CE configuration? 17. Draw and explain sample input and output characteristics for a PNP silicon transistor? 18. Explain the steps and procedures to find dynamic input resistance of the transistor at a

given voltage? 19. Common emitter configuration is the most widely used amplifier circuit. Discuss.

15Mark questions

20. How β is related to α? Compare each parameter of Different transistor configuration. 21. Explain Input and Output Characteristics CB and CE configurations. 22. Explain the procedures to obtain the Q-point of a given transistor in CB configuration? 23. Explain the requirements of biasing circuit and list out the different biasing circuits in

detail? 24. (a)Compare each parameter of Different transistor configuration

b)Compare different transistor biasing circuits? 25. Explain Collector to base Bias circuit, Voltage Divider bias circuit with diagram and

voltage equations. 26. Explain input and output characteristics of different transistor configurations in detail? 27. (a) Explain Amplifying action of transistor -------8mark

(b) Explain the relationship between transistor currents? ----------7mark



Unit III


1. Amplifier with…………..…….feedback circuit is called an oscillator. (a) Positive (b) Negative (c) Both a and b (d) None of these Page | 9

2. A signal generator working on DC Power supply is known as? (c) Oscillator (b)Transistor (c) Amplifier (d) Signal Amplifier

3. What is the phase shift offered by an inductor ? (a) 0 (b) 90 (c) 180 (d) 360

4. Any circuit which generate an alternating voltage is called?

(a)Oscillator (b)Transistor (c) Amplifier (d) Signal Amplifier

5. Among the following given below which can be employed for dielectric heating. (a)Oscillator (b)Transistor (c) Amplifier (d) Signal Amplifier

6. Select the odd one. (a)LC oscillator (b) RC Oscillator (c) RL Oscillator (d) crystal Oscillator.

7. The circuits which generate square waves or pulses are usually called. (a) Multi-vibrators (b)Transistor (c) Amplifier (d) Signal Amplifier

8. An electronic oscillator is better than a mechanical one because (a) it has better frequency stability (b) It has higher efficiency (c) it can produce 20-200Hz (d) none of these

9. The minimum number of RC sections required in Phase Shift Oscillator. (a) two (b) three (c) four (d) none

10. Barkhausen criteria for sustained oscillation gives. (a) Aβ=0 (b) – Aβ=1 (c) A=β (d) A/β

11. In a feedback oscillator, constant amplitude oscillation are obtained when loop gain –Aβ equals (a) 0 (b) 1 (c) -1 (d) α

12. A Colpitt’s oscillator uses (a)A tapped inductor (b)A tapped Capacitor (c) Both (a) and (b) (d) None of these.

13. A Hartley oscillator use (a)A tapped inductor (b)A tapped Capacitor (c) Both (a) and (b) (d) A tapped inductor for inductive feedback.

14. A certain has a top on the inductor in the tank circuit. This oscillator is probably. (a) a Colpitts Oscillator (b) a Clapp Oscillator (c) a crystal oscillator (d) a hartley oscillator

15. For sustaining oscillation in an oscillator: (a) Feedback factor should be unity (b) Phase shift should be zero (c) feedback should be negative (d) Both (a) and (b)



16. To produce 1MHz signal, the most suitable signal is : (a)Phase shift oscillator (b)Wein bridge oscillator (c) Colpitts Oscillator (d) None of these

17. If Barkhausen criteria is not fulfilled by an oscillator circuit, it will (a)Stop Oscillating (b) produce damped waves continously (c)Become an amplifier (d) produce high frequency Whistles.

Page | 10

18. what do phase shift oscillator, twin T oscillator and Wein bridge Oscillators have in common (a)They use RC freequency control (b)they have a sinusiodal output (c) they use amplifier gain to overcome feedback loss (d)all of these

19. which of the following is not true. (a)an oscillator is a circuit converts ac to dc (b)an oscillator is an amplifier that supplies its own input signal (c) an oscillator that generate sine wave (d)in-phase feedback is called positive feedback.

20. Frequency of oscillation of a Wiein bridge oscillator is given by (a)1/6πRC (b) 1/2πRC (c) 1/πRC (d) 1/RC

2mark questions

1. Calculate the output frequency of given LC oscillator having Inductance 200 µH and a capacitance of 500pF.

2. Classify Oscillator. 3. Draw the block diagrams for open and closed loop systems. 4. Write down an expression to find frequency in an LC Oscillator. 5. Explain the term back emf in an Inductor. 6. Classify the sinusoidal oscillators. 7. What are the basic requirements of an oscillator? 8. What is the application of an oscillator? 9. Write down the expression to find frequency of oscillation in Wein Bridge Oscillator. 10. Write down the expression to find frequency of oscillation in Phase shift Oscillator.



4mark questions

1. Draw and explain tuned collector oscillator circuit. 2. Draw and explain Hartley oscillator circuit. 3. Write the major distinction between degenerative and regenerative feedback.

Page | 11 4. Explain Barkhausen criteria for oscillation. 5. Compare amplifier and oscillator. 6. The tuned oscillator circuit used in the local oscillator of a radio receiver make use of an

LC tuned circuit with L=68.3µH, and C=250pF. Calculate the frequency of oscillation. 7. The tuned oscillator circuit used in the local oscillator of a radio receiver make use of an

LC tuned circuit with L=58.6µH, frequency of oscillation in the circ.uit is 1200.35kHz 8. Derive an expression to find frequency in an LC Oscillator. 9. Explain how a tuned LC circuit can be used for generating sine wave. 10. Draw the damped oscillation curve in an LC circuit. 11. Draw and explain Hartley oscillator circuit and Colpitts Oscillator. 12. Draw and explain how a positive feedback can be used as an oscillator. 13. Derive an expression to find out the gain in positive feedback amplifier. 14. Explain feedback and classify them. 15. The tuned oscillator circuit used in the local oscillator of a radio receiver make use of an

LC tuned circuit with L=58.6µH, and C=300pF. Calculate the frequency of oscillation. 16. Compare the advantages and disadvantages of positive and negative feedback circuits.



15Mark questions

1. Classify and explain different types of LC Oscillator in detail. 2. Classify LC & RC oscillator circuit and explain any one of RC oscillator using diagrams. 3. (a) Derive the expression for the frequency of oscillation of Hartley ans Colpitts

oscillator.-------6mark Page | 12

(c) Write the major distinction between degenerative and regenerative feedback ---5mark (d) Draw and explain Hartley oscillator circuit------4mark

4. Classify LC & RC oscillator circuit and explain any one of LC oscillator using diagrams. 5. (a) Explain feedback in detail.-------6mark

(e) Write the major distinction between degenerative and regenerative feedback ---5mark (f) Draw and explain Hartley oscillator circuit------4mark



Unit IV


1. The wave used for telecommunication is. (a)UV (b) X-ray (c) Infrared (d) Microwave Page | 13

2. Which of the following frequencies for the communications is not reliable. (d) 100GHz (b) 100KHz (c) 150MHz (d) 2MHz

3. Indicate which one of the following is the advantage of FM over AM (a) Lesser bandwidth is required (b) allow the use of practical antenna

(c)Transmitted power is more useful (d) less transmitting distance.

4. AM is used for broadcasting because… (a) It is more immune than other (b) It require less transmitting power (c) it avoids receiver complexity (d) Of the faithful transmission and reception

5. Which is not an effect of our environment on wave propagation?

(a) Radiation (b) reflection (c) refraction (d) diffraction

6. A point in space that radiates electromagnetic energy equally in all directions is called (a)Transverse (b) Isotropic point source (c) Omni sphere (d) Shadow zone

7. The process whereby waves travelling in straight paths bend around an obstacle is (a)Radiation (b) Reflection (c) Refraction (d) Diffraction

8. Which is not one of the basic modes of getting a radio wave from the transmitting to the receiving antenna? (a)Ground wave (b) shadow wave (c) space wave (d) Satellite link

9. The type of wave that is most affected by the layers of ionosphere is (a) Ground wave (b) space wave(c) sky wave (d) Satellite link

10. The largest frequency that will be returned to earth when transmitted vertically under given ionosphere condition is called (a)Critical frequency (b) Maximum usable frequency(c) Optimum working frequency (d) Skip zone

11. A common type of radio wave interference is (a)EMI (b) Fading (c) Reflections (d) All of these

12. AM and FM are examples of …………. conversion (a)Digital to digital (b) Digital to analog (c) Analog to analog (d) Analog to digital

13. In QAM ………of a carrier frequency are varied. (a)Frequency and amplitude (b) phase and frequency (c) amplitude and phase (d) none of these

14. ……..conversion is the process of changing one of the characteristics of an analog signal based on the information in the digital data.



(a) Digital to digital (b) Digital to analog (c) Analog to analog (d) Analog to digital

15. Analog to analog conversion is needed if the available bandwidth is ……….. (g) Low-pass (b) band pass (c) Neither (a) or (b) (d) Either (a) or (b) Page | 14

16. In ……….. transmission the carrier signal is modulated so that its amplitude varies with the changing amplitudes of the modulating signal (a)IS (b) FM (c) PM (d) None of these?

17. The process of superimposing AF or VF wave with a high frequency carrier is called (a) Interference (b) diffraction (c) modulation (d) Demodulation

18. Indicate which of the following system is digital. (a)Pulse position modulation (b) Pulse code modulation (c) pulse width modulation (d) pulse amplitude

19. The data transmission rate of a modem is measured in (a)Byte per second (b) Bits per second (c) Hz (d) MHz

20. A wave characterized by having its direction of propagation perpendicular to its oscillation is known as. (h) Isotropic (b) transverse (c) Polarized (d) Refractive

2mark questions

1. Define communication. 2. Name the three blocks in any communication systems. 3. Draw the block diagram for communication systems. 4. What are the requirements of a good carrier wave? 5. Define modulation Index. 6. Why long distance radio stations use SW transmission. 7. What is a communication channel? 8. Name the two regions of AM band. 9. What are the different modes of propagation in space communication? 10. Give the upper limit of frequency of EM wave used in AM transmission. 11. What is a ground wave? 12. The ground wave transmission is possible at frequencies less than 2 MHz explain why? 13. Name the main source of energy loss in a transmission line. 14. The sky waves are not used in TV transmission. Explain why. 15. Give one of the factors by which the range of transmission by TV tower can be increased. 16. Name the common modulation technique employed for digital data transmission.



4mark questions

1. Distinguish analog and digital communication. 2. What are the characteristics of a good radio receiver? 3. Different broadcasting stations used different carrier frequencies. Explain why.

Page | 15 4. Explain different communication lines? 5. Explain the need for modulation. 6. Explain briefly the amplitude modulation. 7. Explain briefly the frequency modulation. 8. Derive an expression for the range of the space wave in terms of the height of an antenna. 9. Explain the different blocks of a communication system in detail. 10. Explain base modulator? 11. Explain collector modulator? 12. Explain diode detector? 13. Note down the types of communication system. 14. Explain pulse code modulation. 15. Name the different advantage and disadvantage of a FM over AM 16. Why do we modulate a signal in communication? 17. The direct transmission of message as electromagnetic wave is having certain drawbacks.

Explain. 18. Explain sinusoidal wave modulation. 19. How can we avoid overlapping of different channels?



15Mark questions

1. (a)why should we modulate a signal, explain different method of modulation for different signals------------8mark

(b)Explain and compare different radio propagation methods----------7mark Page | 16

2. (a)Explain different types of analog carrier modulation. Give their merits and demerits.

(b)Explain and compare different radio propagation methods----------7mark

3. (a)Explain different types of analog carrier modulation. Give their merits and demerits. -----------8mark

(b)Explain satellite communication. Describe briefly remote sensing and remote sensing satellites ----------7mark

4. (a)Explain radio transmitter and receiver by drawing their circuit diagram ----------8mark

(b)Explain the different modulators/demodulators used in communication ----------7mark

5. (a)Explain radio transmitter and receiver by drawing their circuit diagram ----------8mark (i) Explain and compare different radio propagation methods--------------------------7mark

6. Explain AM modulators and AM detectors in detail.



Unit V


1. JFET terminal "legs" are connections to the drain, the gate, and the (a) channel (b) source (c) substrate (d) cathode Page | 17

2. A junction field effect transistor is having how any diodes (a) 1 (b) 2 (c) 3 (d) 4

3. A MOSFET has how many terminals? (a) 2 or 3 (b) 3 (c) 4 (d) 3 or 4

4. JFET terminal "legs" are connections to the drain, the gate, and the (b) channel (b) source (c) substrate (d) cathode

5. The input impedance of a MOSFET is (a) Less than FET but more that BJT (b) More than that of FET and BJT (c) More than FET but less than BJT (d) Less that FET and BJT

6. MOSFET uses the electric field of (b) Gate capacitance to control the channel current (b) Barrier potential of PN junction

to control the channel (c) Both (a) and (b) (d)None of these 7. A depletion MOSFET differs from JFET in the sense that has no

(c) channel (b) gate (c) PN junction (d) substrate 8. The extremely high input impedance of MOSFET is primarily due to

(a) Absence of its channel (b) Negative gate source voltage (c) Depletion of electric current carrier (d) Extremely small leakage electric current of its gate capacity

9. What does the MOS stands for (c) Metal oxide silicon (b) Metal oxide semiconductor (c) Metal on silicon (d)

None of these 10. Which of the following is expected to have highest input impedance

(d) MOSFET (b) JFET amplifier (c) CE bipolar transistor (d) Common collector bipolar transistor

11. The transit time of the electric current carriers through the channel of a JFET decides it’s ………characteristics. (a) Source (b) drain (c) gate (d) source and drain

12. Which of the following are operational amplifiers used? (d) oscillators (b) filters (c) instrumentation circuits (d) all of these

13. In the differential amplifier circuits which of the following terminals are connected together. (e) bases (b) collectors (c) one base to another collector (d) emitters

14. What is the level of the voltage between the input terminals of an op-amp? (a) Zero (b) 5 V (c) 18V (d) 22V

15. What is the voltage gain of the unity followers? (e) 0 (b) 1 (c) -1 (d) ∞




Page | 18

16. The output signal of an op-amp is ………out of phase with its input signal connected to the inverting input terminal (f) 0 (b) 90 (c) 180 (d) 270

17. In order for a BJT to conduct under the conditions of no signal input, the bias must be

(a) In the reverse direction at the E-B junction, sufficient to cause forward break over. (b) In the reverse direction at the E-B junction, but not sufficient to cause avalanche effect. (c) Such that the application of a signal would cause the transistor to go into a state of cutoff. (d) Such that the application of a signal would cause the transistor to go into a state of saturation.

18. You need to design a relaxation oscillator circuit. The most likely device to use might be (a) AN SCR. (b) A UJT. (c) a triac. (d) a 4-layer diode.

19. Which of the following is fastest switching device. (a)JFET (b)MOSFET (c) UJT (d)TRIAC

20. ________ is a mathematical process for determining the rate of change of a function (a) Integration (b) Differentiation (c) Summing (d) Comparatoring

2mark questions

1. Explain the basic theory of FET. 2. What is mean by Pinch off voltage? 3. What are the 4 leads of a junction transistor and also explain functions of each leads. 4. Why bipolar junctions are so called. 5. What are the different operating regions of BJT? 6. Draw the symbols of UJT, FET, and MOSFET. 7. Draw the equivalent circuit of Op-Amp. 8. Draw the symbolic diagram of operational amplifier.

4mark

1. Explain UJT. 2. Compare UJT and FET. 3. Explain the working of FET using Static Characteristic graph. 4. Explain MOSFET and how is it differ from a normal FET. 5. Explain differentiator Op-Amp circuit 6. Draw the block diagram of operational amplifier. 7. Explain the features of an ideal op-amp 8. Explain Integrator Op-Amp circuit. 9. Explain summing Op-Amp circuit.

15Mark questions

10. Explain differentiator, Integrator, summing Op-Amp circuits. 11. Explain with diagram and derive the expression for inverting and non inverting amplifier. 12. Explain junction transistor classify and explain in detail.

COURSE CODE: SDC1AE03 (P) COURSE NAME: ELECTRONICS (LAB)

Questions:

1. Construct a full wave Centre tapped rectifier using the given diodes and also verify the obtained results using CRO, and also find the ripple factor.

2. Construct a full wave Bridge rectifier using the given diodes and also verify the obtained results using CRO, and also find the ripple factor.

3. Given an npn transistor. Measure the value of βdc using suitable circuit. 4. Determine the value of αac of the given npn transistor. 5. For the given transistor find out the value of βdc 6. Obtain the voltage current characteristics of a Zener diode and verify its operation as a

voltage regulator? 7. Obtain the transfer characteristics of CB transistor configuration. And also find the ac, dc

current gain. 8. Obtain the transfer characteristics of CE transistor configuration, and also find the ac, dc

current gain. 9. Construct a CE amplifier using given diodes and obtain its frequency frequency

characteristics. 10. Obtain the wave form as shown in the figure.

11. Obtain the wave form as shown in the figure.

12. Design a LC oscillator (Hartley) using the given capacitor. 13. Design a LC oscillator (Colpitt’s) using the given capacitor 14. Convert a sine wave into cosine wave using suitable circuit. 15. Convert a square wave into triangular wave using suitable circuit. 16. Design and implement an inverting amplifier using IC 741. 17. Design and implement a non- inverting amplifier using IC 741. 18. Design and implement a voltage follower using IC 741. 19. Realize AND- gate using the given diodes. 20. Realize OR- gate using the given diodes. 21. Realize NOT- gate using the given diode and transistor. 22. Design and implement Half adder circuit using NAND-gate and decade counter. 23. Design and implement a phase shift oscillator. 24. Design and implement a circuit to double the voltage.

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