EX-504-A Industrial Electronics - May 2024 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aWith a neat sketch Explain about operation of voltage regulator.
   How to answer

   • Define voltage regulator and need for constant output voltage
   • Block/circuit diagram with neat sketch and labeling
   • Step-by-step operation during line/load variation
   • Role of control element and feedback
2. 7 Marks
   bDifferentiate between series and shunt type voltage regulators.
   How to answer

   • Define series type regulator and its connection
   • Define shunt type regulator and its connection
   • Tabular comparison on efficiency, application, current handling
   • Merits/demerits conclusion
3. 7 Marks
   aDiscuss in detail about the inverting and non inverting modes of OP-AMP.
   How to answer

   • OP-AMP inverting mode circuit, virtual ground concept
   • Gain derivation $A_v = -R_f/R_1$ with waveforms
   • OP-AMP non-inverting mode circuit
   • Gain derivation $A_v = 1+R_f/R_1$ and comparison
4. 7 Marks
   bDraw and explain about switched mode voltage regulator.
   How to answer

   • Circuit diagram of switched mode voltage regulator
   • Switching ON/OFF operation and duty cycle control
   • Role of inductor, capacitor, diode and PWM
   • Advantages like high efficiency
5. 7 Marks
   aDiscuss the operation of single phase full wave rectifier with RE load. Also derives its average output voltage equations.
   How to answer

   • Circuit and waveforms of single phase full wave rectifier with RE load
   • Conduction intervals and effect of back EMF
   • Integration steps for average output voltage
   • Final expression for $V_{dc}$
6. 7 Marks
   bWrite a short note on switched regulator.
   How to answer

   • Definition and need of switched regulator
   • Basic block diagram and switching principle
   • Types/features in brief
   • Applications/advantages
7. 7 Marks
   aWhat are the various causes of damage to SCR, explain in detail.
   How to answer

   • List causes: overvoltage, overcurrent, high dv/dt, di/dt, overheating
   • Explain each damage mechanism in SCR
   • Gate drive and commutation failures
   • Protective measures overview
8. 7 Marks
   bWith neat sketch explain the operation of SCR overvoltage protection circuit.
   How to answer

   • Neat sketch of SCR overvoltage protection circuit with suppressor
   • Sources of overvoltage transients
   • Operation of snubber/crowbar protection
   • How SCR is clamped/protected
9. 7 Marks
   aExplain the principle of operation and draw the characteristics of IGBT.
   How to answer

   • Structure and symbol of IGBT
   • Principle of operation with MOSFET-driven BJT action
   • Output and transfer characteristics sketch
   • Key features and applications
10. 7 Marks
    bExplain the principle of operation and draw the characteristics of MOSFET.
    How to answer

    • Structure and symbol of MOSFET (power MOSFET)
    • Principle of operation with gate-controlled channel
    • Output and transfer characteristics sketch
    • Key features and applications
11. 7 Marks
    aExplain the block diagram of PLC and how PLC's are used in microprocessor?
    How to answer

    • Block diagram of PLC with CPU, I/O, memory, power supply
    • Function of each block
    • How PLC interfaces with microprocessor system
    • Scan cycle and industrial use
12. 7 Marks
    bExplain the concept of low pass filters with OP-AMP.
    How to answer

    • Basic low pass filter concept and cutoff frequency
    • OP-AMP based active low pass filter circuit
    • Frequency response and gain expression
    • Applications
13. 14 Marks
    Explain the working principle of the following:

    1. a)Relaxation oscillator
    2. b)Window comparator
    3. c)Wien bridge oscillator
    How to answer

    • Relaxation oscillator: charging/discharging and frequency
    • Window comparator: dual thresholds and output logic
    • Wien bridge oscillator: bridge balance and oscillation condition
    • Circuit diagrams and waveforms for each
14. 7 Marks
    aWhat are the different types of commutation methods ? Explain in detail with neat sketches.
    How to answer

    • Define commutation and need in SCR circuits
    • Types: natural, forced, class A-F with neat sketches
    • Operation of each method stepwise
    • Comparison of applications
15. 7 Marks
    bJustify how the loss of power in semiconductor devices.
    How to answer

    • Sources of loss: conduction, switching, leakage
    • Power loss mechanisms in semiconductor devices
    • Effect on efficiency and heating
    • Justification with expressions/waveforms