24031-ELECTRONIC DEVICES AND CIRCUITS IMPORTANT QUESTIONS

DIPLOMA IN ELECTRICAL AND ELECTRONICS ENGINEERING

SUBJECT CODE   : 24031 

SEMESTER           : III SEMESTER

 SUBJECT TITLE   : ELECTRONIC DEVICES AND CIRCUITS  

STAFF-IN-CHARGE: N.DILLIBABU

IMPORTANT QUESTIONS

UNIT-I

PART-A

1.     Give an example for donor impurity.

2.     What is the cut in voltage for silicon diode?

3.     What is the peak inverse voltage of full wave rectifier?

4.     Name a component used for filtering.

5.     Give an example for intrinsic semiconductor.

6.     Draw the symbol of Zener diode

7.     What is the efficiency of half-wave rectifier?

8.     How many filtering components are used in pi filter?

PART-B

1.     Explain the operation of Zener diode and draw characteristics.(oct-12,13,14)

2.     Explain the operation of full wave rectifier and draw its output waveforms. List out its applications.(apr-13,14)

3.     Explain the operation and characteristics of PN junction diode with suitable diagram.(apr-13,14)

4.     Explain the operation of C and pi filter and draw its waveform.

5.     With a neat diagram , explain the working of  bridge rectifier.(oct-12,13,14)

UNIT-II

PART-A

1.     Draw the symbol of NPN transistor.

2.     What is the formula for current gain in common emitter configuration?

3.     Which bias is normally used in applications?

4.     What is the need for negative feedback?

5.     In which region transistor has to be operated for faithful amplification?

6.     What is the output impedance of common base configuration?

7.     What is Q-point?

8.     Name the types of feedback

PART-B

1.     (i) Explain the operation of transistor as an amplifier.(oct-12)

(ii) Write short notes on fixed bias. (apr-13)

2.     (i) Explain the operation of emitter follower.

(ii) Explain how transistor is used as a switch(apr-13)

3.     (i)Explain the operation of NPN transistor.

(ii) Compare three different configurations of transistors. (apr-13)

4.     Explain the operation of RC coupled(oct-12) amplifier and draw its frequency response.

5.     Explain the effect of  negative feedback(oct-12)

6.     Explain the operation of  BJT(oct-13)

UNIT-III

PART-A

1.     What is the condition for oscillation?

2.     What is the output frequency of Heartley oscillator?

3.     Mention the relationship between the parameters of JFET.

4.     State any two applications of UJT

5.     What are the components used in tank circuit?

6.     State the advantages of crystal oscillator.

7.     Give an example for voltage controlled device.

8.     What is the formula for intrinsic standoff ratio?

PART-B

1       (i) Discuss about the conditions for oscillation.

(ii) Explain the operation of RC phase shift oscillator.

2       Explain the working principle of JFET and draw its characteristics.(oct-13)

3       (i) Explain the operation of Hartley oscillator.

(ii) Differentiate FET with BJT (oct-12)

4       Explain the construction and operation of UJT.(apr-13)

5       Explain the operation of crystal oscillator(oct-12)

6       Explain the operation of colpitts oscillator(apr-14)

UNIT-IV

PART-A

1.     Give an example for unidirectional switch.

2.     Draw the symbol of TRIAC.

3.     Name the terminals of DIAC.

4.     Expand MOSFET.

5.     What is the family name of SCR?

6.     How many terminals are present in TRIAC?

7.     Expand DIAC.

8.     What are the types of MOSFET?

PART-B

1       (i) Explain SCR as a controlled rectifier.                                                        ii) Discuss about the specifications of SCR.

2       Explain the operation of  DE-MOSFET with neat diagram.

3       With neat diagram explain the working principle of SCR and draw the transistor analogy of SCR.(oct-12)

4       i)  Explain the operation of DIAC with its characteristics. (apr-13)                               ii) Explain the construction details of MOSFET.

5       Explain the operation of TRIAC with its characteristics.(OCT-13)

UNIT-V

PART-A

1.     Draw the symbol of LDR.

2.     What is solar cell?

3.     Draw the output waveform of negative clamper.

4.     How many stable states are present in Astable  Multivibrator?

5.     In which bias, LED emits light?

6.     Expand LASER.

7.     What is the other name for Astable  Multivibrator?

8.     Draw the output waveform of negative clipper.

PART-B

1.     Explain the operation of Solar cell and Photo Transistor. (APR-13)

2.     Explain the operation of Schmitt Trigger and draw its output waveform.(APR-14)

3.     Explain the operation of  i) Opto interrupter ii) avalanche photo diode. (OCT-14)

4.     Explain the operation of positive and negative clamper.

5.     Explain the operation of CLIPPER(oct-12)

6.     Explain the operation of monostable multivibter(oct-12)

7.     Explain the operation of voltage diubler(oct-12)

8.     LED,LCD.

23032-ELECTRICAL MACHINES-I IMPORTANT QUESTIONS

DIPLOMA IN ELECTRICAL AND ELECTRONICS ENGINEERING

SUBJECT CODE          : 23032

SEMESTER                   : III SEMESTER

SUBJECT TITLE          : ELECTRICAL MACHINES-I

STAFF-IN-CHARGE  : N.SURESH KUMAR

IMPORTANT QUESTIONS

UNIT-I

PART-A

1.     Define Absolute and relative permeability-April 2013

2.     Define Ampere Turn (A.T)-April 2013

3.     State Len’s Law-Apr 2013-April 2014-April 2015

4.     Compare any two factors between Magnetic and Electric circuit

5.     Define Magnetic flux (Φ)-Oct 2012-Oct 2014

6.     State Laws of Magnetic Force (F)-Oct 2012-Oct 2013

7.     State Fleming’s Left Hand Rule-April 2014

8.     Explain Mutual Induction

9.     Define Intensity of Magnetization -Oct 2012

10.            State Fleming’s Right Hand Rule-Oct 2012-April 2013-Oct 2013

11.            Define Reluctance –Oct 2013

12.            Write the expression for lifting power of Electromagnet-Oct 2013

13.            Define flux density-April 2014

14.            Write expression for energy stored in magnetic field-April 2014

15.            Define magnetic field intensity-Oct 2014

16.            Derive the Expression of Hysteresis loss-Oct 2014

17.            What is mutually induced emf-Oct 2014

18.            What is magnetic material –April 2015

19.            Write any one application of electromagnet-April 2015

20.            What are two induced emf-April 2015

PART-B

1.     Write short notes on the following:

Hystersis Losses & Eddy Current Losses (6) (12)- April 2014-April 2015

2.     Explain statically Induced EMF with neat diagram (6)-April 2014

3.     Derive force on a current carrying conductor lying in a Magnetic field. (6)- oct 2012

4.     Define Magnetic field strength (H), flux density (B), Intensity of Magnetization (I) (6)-April 2013

5.     Derive Lifting Power of Electro magnet (6)-April 2014

6.     Explain dynamically induced emf.(12) (6)- Oct 2013-April 2015

7.     Explain self induced emf (6) – oct 2012

8.     Compare magnetic and electric circuits (6)-April 2013-Oct 2013-April 2015

9.     Faraday’s law of electromagnetic induction (6)-Oct 2014

10.                        Explain the significance of hysteresis loop of a magnetic specimen (6)-Oct 2014

UNIT-II

PART-A

1.     What is Lap winding?-Oct 2012

2.     What is the condition for self excitation?-April 2013

3.     Draw the circuit for DC series Generator

4.     State any two application of compound generator-April 2013

5.     What is wave winding?-April 2013

6.     Explain separately excitation

7.     Define Back pitch and Front pitch

8.     What is an Armature?

9.     What is the function of commutator in DC generator-Oct 2014

10.                        Define critical field resistance in Dc generator-Oct 2014

11.                        What is the function of brush-Oct 2014

12.                        What are the methods used to compensate armature reaction in DC generator?-Oct 2014

13.                        Where to use lap winding?-Apr 2014

14.                        Mention any two losses in Dc generator.-Apr 2014-Oct 2013

15.                        Draw the load characteristics curve of Dc shunt Generator.-April 2014

16.                        Define armature reaction-April 2014

17.                        Mention any two applications of Dc generator.-Oct 2013-Oct 2012

18.                        Mention the purpose of doing Swimburne’s test-Oct 2013

19.                        Write the expression for emf equation in DC machines-Oct 2013

20.                        Mention the types of armature winding in Dc Machines-Oct 2013

21.                        Name the various parts of Dc generators.-Oct 2012

22.                        Write the expression for Dc generator-Oct 2012

23.                        What is separately excited DC generator-Apr 2015

24.                        What is the internal characteristics of DC Generator?-April 2015

25.                        List the methods to compensate the armature reaction-April 2015

PART-B

1.     Drive EMF equation of a DC Generator (6) – Oct 2012-April 2013-April 2014-April 2015

2.     Explain Load Characteristics of a DC shunt Generator (6)-Oct 2013

3.     Explain the 3 components of a DC Machine Field System,Commutator,Yoke(6)-Oct 2014

4.     Explain constructional details of a DC Generator (12)-April 2014-April 2015

5.     Explain an Armature reaction with neat diagram (12)-Oct 2012-Oct 2013-April 2014-April 2015

6.     Methods of compensation of Armature reaction (6)-April 2013-Oct 2013

7.     Develop the winding diagram for 24 slots 4 poles 4 poles single layer lap winding (6) – april 2013

8.     Explain the working principle of DC Generator (6)-Oct 2013

9.     Types of DC Generator (6)-Oct 2013

10.                        No-load characteristics of DC Shunt Generator (6)-April 2014

UNIT-III

PART-A

1.     Draw the Speed-Torque curve of a DC series Motor-April 2014

2.     What are the Speed Control factors?

3.     Draw the circuit diagram of a DC series Motor

4.     Write any 2 application of DC Shunt Motor

5.     Define Back emf.-Oct 2013-April 2015

6.     Write the Torque equation of a DC Motor-Oct 2012-April 2014-Oct 2014

7.     Explain Critical Resistance

8.     State any two applications for a DC series motor-Oct 2013

9.     What is the principle of DC Motor?-Oct 2012

10.                        Write the power stages of DC Motor.-Oct 2012

11.                        State which type Dc Motor is suitable for (i) Centrifugul pump (ii) Electric trains-Oct 2012

12.                        Write the expression for back emf in DC Motor-April 2013

13.                        What are the three points of DC shunt Motor starter?-April 2013

14.                        What are the factors which control Dc Motor speed?-April 2013

15.                        What are the applications of DC Compound motor?-April 2013

16.                        Mention the two methods of Dc motor control.-Oct 2013

17.                        What is called commutation?-Oct 2013-Oct 2014

18.                        Write the expression for torque equation in Dc Motor-April 2014

19.                        What is the necessity of starters?-April 2014-Oct 2014

20.                        What are the different losses occurring in Dc motor?-Oct 2014

21.                        Mention the types of starters used in DC Motor-April 2015

22.                        Dc series motor is preferred for traction purpose why?-April 2015

23.                        Name the two protective devices used in three point starter.-April 2015

PART-B

1.     Explain working principle of operation of DC Motor (6)-Oct 2012-April 2014-April 2015

2.     Develop the Torque equation of the DC Motor (6)-Oct 2012-Oct 2013-Oct 2014

3.     Explain commutation with neat diagram. (6)-April 2014

4.     Explain 3 point starter with neat diagram (6)-Oct 2013-April 2015

5.     Explain Armature control and field control method (12)-Oct 2012-Oct 2013

6.     Explain 4 point starter with a neat diagram (12)-April 2014

7.     Types of DC motor and voltage equations (6)-April 2013

8.     Explain Armature torque and shaft torque (6) –April 2013

9.     Characteristics of Dc shunt motor (6)-Oct 2013

10.                        Explain the char of compound generator(6) –Oct 2014

11.                        Different field control methods of Dc Series motor (6)- Oct 2014

12.                        Load test on DC compound motor (6)-Oct 2014

13.                        Explain how the speed is controlled in DC Shunt motor by armature and field control methods.(6)-April 2015

14.                        What are the methods of improving commutation in Dc motor? (6)-April 2015

UNIT-IV

PART-A

1.     Why transformer rating is always in KVA?-Oct 2012

2.     Draw No Load Vector Diagram of a Single Phase Transformer.-April 2013

3.     What is the condition for Maximum efficiency?-Apr 2013

4.     Write any two advantages of Parallel Operation

5.     Define Voltage transformation ratio-Oct 2014

6.     Define Regulation-Oct 2012

7.     What is Auto transformer?-Oct 2012

8.     What are the conditions for 2 single phase transformer parallel?

9.     On what principle does the transformer works?-April 2015

10.                        State the different connections of three phase distribution transformer-April 2015-Oct 2012

11.                        Mention  the use of breather in transformer-April 2015-Oct 2013

12.                        What are the two test to find losses in transformer?-April 2015

13.                        What is all day efficiency of transformer?-Apr 2013-Oct 2013-Oct 2014

14.                        Mention the use of breather in transformer.-Apr 2013

15.                        Write the expression for emf equation of 1 phase transformer-Oct 2013

16.                        What is the purpose of doing SC test in transformer?-Oct 2013

17.                        Mention the two no load current component.-April 2014

18.                        Mention any one condition of parallel operation of transformer-April 2014

19.                        Mention two methods of connection of 3 phase transformer.-April 2014

20.                        What are the advantages of parallel operation of transformer?-Oct 2014

21.                        Mention the use of Buckholz relay.-Oct 2015

PART-B

1.     Explain working principle of Transformer (6)-Oct 2012

2.     Explain open circuit test with neat diagram(6)

3.     Write about any two 3 phase transformer connection (6)

4.     Write short notes about Buckholz relay (6)-Oct 2012-April 2014-April 2015

5.     Explain Auto Transformer and also write advantages and disadvantages (12)-Oct 2013-Oct 2014-April 2015

6.     Write short notes on Load & Off Load Tap changes(12)-oct 2013

7.     Explain EMF equation of transformer (6)-April 2013

8.     Derive the condition for maximum efficiency of a Transformer (6)-April 2013-Oct 2014

9.     Necessity of tap changing in a distribution transformer (6)-April 2013

10.            Equivalent circuit of single phase transformer (6)-Oct 2013

11.            Explain 4 Cooling methods of transformer (6)-Oct 2013-April 2014-April 2015

12.            Vector diagram of transformer on load with lagging power factor (6)-April 2014-Oct 2014

13.            Write short notes on All day Efficiency (6)-April 2014

14.            Construction of Shell type transformer with advantage and disadvantage (6)-Oct 2014

15.            Draw and explain the phasor diagram of transformer in leading power factor load.-April 2015

UNIT-V

PART-A

1.     What is the use of Silica Gel in Breaker?

2.     Define Secondary Battery-April 2015

3.     What are the indications of fully charged cell for Lead Acid Battery?-April 2015

4.     What is the function of Brush?-Apr 2013

5.     State Faraday’s Law Electrolysis.-oct 2013

6.     What is the active material used in Nickel – Iron cell?

7.      What is specific gravity of H2 SO4?

8.     What is the electrolyte in lead acid cell?-April 2015

9.     Write any three application of Alkaline Battery.-April 2015-Apr 2013

10.            What is primary cell?-Oct 2014-Apr 2013

11.            Define Ampere-hour efficiency-Oct 2014-Apr 2013

12.            What are the requirement of brushes-Oct 2014

13.            Name three causes of sparking in commutators.-Oct 2014-Oct 2012

14.             What is primary battery?-Apr 2014

15.            Mention any two types of brushes-Apr 2014

16.            Mention any two types of resurfacing commutator-Apr 2014

17.            Mention two applications of lead acid cell-Apr 2014

18.            What is the function of brush holder?-Oct 2013

19.            What is the use of growler?-Oct 2013

20.            Compare lead and Edison cell with respect to positive plates-Oct 2013

21.            Define secondary cells.-Oct 2012

22.            What is the active materials used in Nickel iron cell?-Oct 2012

23.            What is meant by trickle charging?-Oct 2012

PART-B

1.     Write common causes of sparking in commutators (6)-April 2014-Oct 2013-Apr 2013

2.     Explain Staggering of Brushes (6)-Oct 2014-Oct 2013

3.     What are Maintenance of Lead Acid Cell (6)

4.     Compare Lead Acid and Edison Cell (6)-Oct 2014-Oct 2012

5.     Explain Growler with neat diagram (12)-Oct 2014-Apr 2014-Oct 2012

6.     Construction of Nickel iron cell (6)-Oct 2014-Oct 2012

7.     Compare primary and secondar5y Batteries (6)-Apr 2014

8.     Explain the two methods of charging storage batteries (6)-Apr 2014

9.     How to find defects in armature windings (6)-Oct 2013

10.         Construction of lead acid cell (6)-Oct 2013-Apr 2013

11.         Explain the functions and requirements of Brushes (6)-Apr 2013.

12.         Explain Faradays law of Electrolysis (6)-Apr 2013

13.         What are the Common effects of commutator? How they are rectified? (6)-Oct 2012

14.         Explain how the faults can be located by conducting voltage drop test (6)-April 2015

15.         Enumerate the electrical characteristics of Edison cell (Nickel - Iron) (6)-April 2015

16.         Explain the chemical reactions and physical changes during discharging and charging of lead acid cell (6)-April 2015

17.         What is resurfacing of commutator? Explain any two methods of resurfacing.-April 2015