Power Electronics & Instrumentation (18EC36)

MODULE I

Module – 1 A) Introduction

Theory Questions
1) What is power electronics? List the various applications of power electronics.
2) Mention and explain the different types of power electronic converter systems. Draw
their input /output characteristics.
3) With the help of neat block diagram explain power electronic system.

4) Mention advantages and disadvantages of power electronic controllers.

Numerical

No numerical in this bit

Prof. Chaitanya K J, Dept. of ECE, JCER, Belagavi. Page 1

 Power Electronics & Instrumentation (18EC36)

MODULE I

Module – 1 B) Thyristors

Theory Questions
1) With the help of neat circuit diagram and waveforms explain V-I characteristics
(static characteristics) of SCR. Hence Define Latching current and Holding current of
SCR.
2) With the help of neat circuit diagram and waveforms explain gate characteristics of
SCR.
3) List the differences between Latching current and holding current of SCR
4) List and explain various turn ON methods of SCR.
5) With the help of waveform explain Turn-ON characteristics of SCR
6) With the help of waveform explain Turn-OFF characteristics of SCR
7) What do you mean by commutation? List and explain types of commutation
8) With the help of neat circuit diagram and waveform explain Class A and Class B type
of commutation.
9) With the help of neat circuit diagram and waveform explain Resistance firing circuit.
10) With the help of neat circuit diagram and waveform explain Resistance capacitance
firing circuit
11) With the help of neat circuit diagram and waveform explain UJT firing circuit.

Numerical

1) Numerical to compute Current through thyristor

2) Numerical to compute Minimum width of gate trigger pulse
3) Numerical to compute Conduction angle
4) Numerical to compute Firing angle in Resistance triggering circuit
5) Numerical to Design RC half wave and full wave triggering circuit
6) Numerical to Design UJT triggering circuit
7) Minimum and maximum triggering frequency in UJT triggering circuit

Prof. Chaitanya K J, Dept. of ECE, JCER, Belagavi. Page 2

 Power Electronics & Instrumentation (18EC36)

MODULE II

Module – 2 A) Phase Controlled Converters

Theory Questions
1) With the help of neat circuit diagram and waveforms explain operation of single
phase half wave controlled rectifier with resistive load and hence derive average
output voltage equation for the same.
2) With the help of neat circuit diagram and waveforms explain operation of single
phase half wave controlled rectifier with resistive inductive load and hence derive
average output voltage equation for the same.
3) With the help of neat circuit diagram and waveforms explain operation of single
phase half wave controlled rectifier with freewheeling diode and hence derive average
output voltage equation for the same. (RL Load with freewheeling diode)
4) With the help of neat circuit diagram and waveforms explain operation of single
phase full wave controlled rectifier with resistive load and hence derive average
output voltage equation for the same.
5) With the help of neat circuit diagram and waveforms explain operation of single
phase full wave controlled rectifier with resistive inductive load and hence derive
average output voltage equation for the same.
6) With the help of neat circuit diagram and waveforms explain operation of single
phase full wave controlled rectifier with freewheeling diode and hence derive average
output voltage equation for the same. (RL Load with freewheeling diode)

Numerical
1) Numerical to compute average output voltage, effective (RMS) output voltage,
average load current
2) Numerical to compute delay angle (alpha)
3) RMS and AVG output current / load currents
4) RMS and AVG thyristor current
5) Numerical to compute Harmonic factor, Distortion factor & power factor

Prof. Chaitanya K J, Dept. of ECE, JCER, Belagavi. Page 3

 Power Electronics & Instrumentation (18EC36)

MODULE II

Module – 2 B) Choppers

Theory Questions
1) Define chopper. Hence classify various types of chopper with suitable equations.
2) With the help of neat circuit diagram and waveforms explain operation of step down
chopper (BUCK). Hence derive equation for average output voltage.
3) With the help of neat circuit diagram and waveforms explain operation of step up
chopper (BOOST). Hence derive equation for average output voltage.
4) With the help of neat circuit diagram and waveforms explain operation of step up /
step down chopper (BUCK-BOOST). Hence derive equation for average output
voltage.
5) With the help of neat circuit diagram and waveforms explain operation of step down
chopper (BUCK). Hence derive equation for RMS (effective) voltage.
6) With the help of neat circuit diagram and waveforms explain operation of step up
chopper (BOOST). Hence derive equation for RMS (effective) voltage.
7) With the help of neat circuit diagram and waveforms explain operation of step up /
step down chopper (BUCK-BOOST). Hence derive equation for RMS (effective)
voltage.
8) With help of neat circuit diagram and waveforms explain four quadrant operation of
chopper.

Numerical
1) Numerical to compute average output voltage, output power, conduction period
(Ton), RMS output voltage

Prof. Chaitanya K J, Dept. of ECE, JCER, Belagavi. Page 4

 Power Electronics & Instrumentation (18EC36)

MODULE III

Module – 3 A) Inverters

Theory Questions
1) With the help of neat circuit diagram and waveforms explain operation of half bridge
inverter having Resistive load. Hence derive equation for RMS output voltage.
2) With the help of neat circuit diagram and waveforms explain operation of half bridge
inverter having Resistive inductive load. Hence derive equation for RMS output
voltage.
3) Discuss the performance parameters related to inverters.
4) With the help of neat circuit diagram and waveforms explain operation of full bridge
inverter having Resistive load. Hence derive equation for RMS output voltage.
5) With the help of neat circuit diagram and waveforms explain operation of full bridge
inverter having Resistive inductive load. Hence derive equation for RMS output
voltage.

Numerical
1) Numerical to compute RMS value of output voltage, RMS value of fundamental
component, total harmonic distortion.

Prof. Chaitanya K J, Dept. of ECE, JCER, Belagavi. Page 5

 Power Electronics & Instrumentation (18EC36)

MODULE III

Module – 3 B) SMPS

Theory Questions
1) With the help of neat block diagram explain operation of SMPS.
2) With the help of neat circuit diagram and waveforms explain operation of flyback

converter. Hence derive output voltage equation for the same.

3) With the help of neat circuit diagram and waveforms explain operation of forward

converter. Hence derive output voltage equation for the same.

Numerical
No numerical in this bit

Prof. Chaitanya K J, Dept. of ECE, JCER, Belagavi. Page 6

 Power Electronics & Instrumentation (18EC36)

MODULE III

Module – 3 C) Principle of Measurement

Theory Questions
1) Define measurement. List and explain performance characteristics of an instrument.

2) Define following terms with respect to static characteristics of an instrument

a) Accuracy b) Precision c) Error d) Sensitivity e) Resolution f) Linearity

g) Reproducibility h) Stability

3) Explain with equation absolute error and relative errors.

4) Explain various types of errors related to static errors.

5) List various sources of errors which gets added during measurement.

6) With the help of neat circuit diagram and equation explain basic DC ammeter.

7) With the help of neat circuit diagram and equation explain Multirange DC ammeter.

8) With the help of neat circuit diagram and equation explain Aryton shunt or Universal

shunt DC ammeter.

9) With the help of neat circuit diagram and equation explain basic DC voltmeter.

10) With the help of neat circuit diagram and equation explain Multirange DC voltmeter.

Numerical

1) Numerical to compute Absolute error, % error, relative accuracy, sensitivity,

deflection factor, resolution.

2) Numerical to compute shunt resistance for ammeter (simple, Multirange, Aryton)

3) Numerical to compute series resistance for voltmeter

Prof. Chaitanya K J, Dept. of ECE, JCER, Belagavi. Page 7

 Power Electronics & Instrumentation (18EC36)

MODULE IV

Module – 4 A) Digital Voltmeter

Theory Questions
1) Define digital voltmeters. With help of neat block diagram explain Basic digital
voltmeter (DVM)
2) With the help of neat block diagram explain ramp type digital voltmeter.
3) With the help of neat block diagram explain dual slope integrating type digital
voltmeter.
4) With the help of neat block diagram explain direct compensation type digital
voltmeter.
5) With the help of neat block diagram explain successive approximation type digital
voltmeter.

Numerical
No numerical in this bit

Prof. Chaitanya K J, Dept. of ECE, JCER, Belagavi. Page 8

 Power Electronics & Instrumentation (18EC36)

MODULE IV

Module – 4 B) Digital Multimeter

Theory Questions
1) With the help of neat block diagram explain digital frequency meter (counter)
2) With the help of neat diagram explain function generator.

Numerical
No numerical in this bit

Prof. Chaitanya K J, Dept. of ECE, JCER, Belagavi. Page 9

 Power Electronics & Instrumentation (18EC36)

MODULE IV

Module – 4 C) Bridges

Theory Questions
1) With the help of neat circuit diagram explain Wheatstone bridge. Hence derive
balancing condition for the same.
2) List the advantages and limitations of Wheatstone bridge.
3) With the help of neat circuit diagram explain capacitance comparison bridge (De
Sautys Bridge). Hence derive balancing condition for the same.
4) With the help of neat circuit diagram explain inductance comparison bridge. Hence
derive balancing condition for the same.
5) With the help of neat circuit diagram explain wiens bridge. Hence derive balancing
condition for the same.

Numerical

1. Numerical to compute unknown value of resistance using Wheatstone bridge

2. Numerical to compute unknown value of resistance and inductance using inductance
comparison bridge
3. Numerical to compute unknown value of resistance and capacitance using capacitance
comparison bridge.
4. Numerical to compute unknown value of frequency, values of wiens bridge.

Prof. Chaitanya K J, Dept. of ECE, JCER, Belagavi. Page 10

 Power Electronics & Instrumentation (18EC36)

MODULE V

Module – 5 A) Transducer

Theory Questions
1) Define transducer. List and explain various types of transducer.
2) List the characteristics of transducer
3) List the factors for selection of transducer
4) Write a short note on following transducer
a) Resistive transducer
5) Explain the construction and operation of resistance temperature detector (RTD)
6) Define thermistor. Explain construction and operation of thermistor.
7) Explain operation of linear variable differential transformer (LVDT)
8) Explain the operation of instrumentation amplifier using transducer bridge.

Numerical
No numerical in this bit

Prof. Chaitanya K J, Dept. of ECE, JCER, Belagavi. Page 11

 Power Electronics & Instrumentation (18EC36)

MODULE V

Module – 5 ) Programmable Logic Controller

Theory Questions
1) Define PLC. Explain with block diagram process control system.
2) What is ladder logic. Draw and list various ladder diagram elements
3) Compare relay logic with PLC based system
4) With neat block diagram explain architecture of PLC.
5) Difference between PLC and PC

Numerical
No numerical in this bit

Prof. Chaitanya K J, Dept. of ECE, JCER, Belagavi. Page 12