Previous year question paper for PE (Diploma Electronics & Communication Engineering 4th)

1. Introduction to thyristors and other Power Electronics . . . . .

Devices (18 hrs)

1.1 Construction, Working principles of SCR, two transistor analogy of

SCR, V-I characteristics of SCR.

1.2 SCR specifications & ratings.

1.3 Different methods of SCR triggering.

1.4 Different commutation circuits for SCR.

1.5 Series & parallel operation of SCR.

1.6 Construction & working principle of DIAC, TRIAC & their V-I

characteristics.

1.7 Construction, working principle of UJT, V-I characteristics of UJT.

UJT as relaxation oscillator.

1.8 Brief introduction to Gate Turn off thyristor (GTO), Programmable unijunction

transistor (PUT).

1.9 Basic idea about the selection of Heat sink for thyristors.

1.10 Applications such as light intensity control, speed control of

universal motors, fan regulator, battery charger.

2. Controlled Rectifiers (08 hrs)

2.1 Single phase half wave fully controlled rectifier with R & R-L load.

2.2 Single phase half controlled full wave rectifier with R & R-L Load.

2.3 Single face fully controlled full wave bridge rectifier R & R-L Load.

2.4 Single phase fully controlled full wave centre tap rectifier R & R-L

Load.

3. Inverters, Choppers, Dual Converters and Cyclo converters.

 (16 hrs)

3.1 Principle of operation of basic inverter circuits, concepts of duty

cycle, series & paralle inverters & their applications.

3.2 Choppers: Introduction, types of choppers (Class A, Class B, Class

C and Class D). Step up and step down choppers.

3.3 Dual Converters and cyclo converters: Introduction, types & basic

working principle of dual converters and cyclo converters & their

applications. 

4. Thyristorised Control of Electric drives (14 hrs)

4.1 DC drive control

i) Half wave drives.

ii) Full wave drives

iii) Chopper drives (Speed control of DC motor using

choppers)

 4.2 AC drive control

i) Phase control

ii) Constant V/F operation

iii) Cycloconverter/Inverter drives.

5. Uninterrupted Power supplies (08 hrs)

 5.1 UPS, on-line, off line & their specifications

 5.2 Concept of high voltage DC transmission

 5.3 Idea of SMPS