EC-302 Electronic Measurements and Instrumentation - Dec 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
   aList out different AC voltmeters and explain the working of any one voltmeter in detail.
   How to answer

   • List types of AC voltmeters - average responding, peak responding, true RMS, etc.
   • Select any one type for detailed explanation
   • Explain working with circuit/block diagram and operation
   • Mention measurement principle and applications
2. 7 Marks
   bExplain different static characteristics of instrument and measurement system.
   How to answer

   • Define static characteristics of instruments
   • Explain accuracy, precision, sensitivity, resolution, linearity
   • Explain drift, hysteresis, dead zone, repeatability
   • Relevance to measurement system performance
3. 7 Marks
   aDraw the block diagram of CRO and explain different parts of CRO.
   How to answer

   • Draw labelled block diagram of CRO
   • Explain CRT, electron gun, deflection system, screen
   • Explain vertical/horizontal amplifiers and time base
   • Explain trigger, power supply and controls
4. 7 Marks
   bDraw the circuit diagram of sampling oscilloscope and explain its operation in detail.
   How to answer

   • Draw circuit diagram of sampling oscilloscope
   • Explain sampling gate, staircase generator and sampling principle
   • Explain sequential sampling for high frequency signals
   • Mention advantages and applications
5. 7 Marks
   aDraw the circuit diagram of Hay's bridge and explain its operation.
   How to answer

   • Draw circuit diagram of Hay's bridge with inductor, resistors and capacitor
   • Explain balance condition derivation
   • Explain phasor operation and use for high-Q inductors
   • Mention advantages and limitations
6. 7 Marks
   bDiscuss the condition during which the bridge sensitivity is maximum for a detector.
   How to answer

   • Define bridge sensitivity with respect to detector
   • Derive condition for maximum power transfer to detector
   • Discuss impedance matching of detector and bridge arms
   • State condition for maximum sensitivity
7. 7 Marks
   aExplain the working principle of LVDT with diagram.
   How to answer

   • Draw construction of LVDT with primary and two secondary windings and movable core
   • Explain mutual induction and differential output principle
   • Explain output variation with core displacement - null, in-phase, out-of-phase
   • Mention characteristics and applications
8. 7 Marks
   bExplain the photo-diode in detail.
   How to answer

   • Define photo-diode and its construction
   • Explain working under reverse bias and illumination
   • Explain V-I characteristics and modes of operation
   • Mention applications in instrumentation
9. 7 Marks
   aDescribe the working of pulse wave generator with diagram.
   How to answer

   • Draw block/circuit diagram of pulse wave generator
   • Explain pulse generation, timing and shaping circuits
   • Explain frequency, width and amplitude control
   • Mention specifications and uses
10. 7 Marks
    bDiscuss about the working of LCD in detail.
    How to answer

    • Define LCD and its types
    • Explain construction with liquid crystal cell and polarizers
    • Explain working based on light polarization/scattering
    • Compare advantages, limitations and applications
11. 7 Marks
    aDraw a weighted resistor DAC and obtain the transfer characteristic of a 3 bit DAC.
    How to answer

    • Draw weighted resistor DAC circuit with op-amp summer
    • Explain binary-weighted resistors and switching operation
    • Derive output voltage expression
    • Sketch/obtain transfer characteristic for 3-bit DAC
12. 7 Marks
    bDraw and explain the operation of dual slope integrating type ADC.
    How to answer

    • Draw block/circuit diagram of dual-slope integrating ADC
    • Explain integration phase and de-integration phase
    • Explain role of counter, comparator and control logic
    • Mention advantages like noise rejection and accuracy
13. 7 Marks
    aFind out step size and analog output for 4 bit R-2R ladder DAC, when input is 0111 and 1111, assume $V_{ref}=+5V$.
    How to answer

    • State step size formula $V_{ref}/2^n$ and compute for n=4, $V_{ref}=5V$
    • State R-2R ladder output formula $V_o = V_{ref} \times D/2^n$
    • Calculate analog output for input 0111 (decimal 7)
    • Calculate analog output for input 1111 (decimal 15)
14. 7 Marks
    bExplain the resolution and sensitivity of DVM in detail.
    How to answer

    • Define resolution of DVM
    • Define sensitivity of DVM
    • Explain factors affecting resolution and sensitivity
    • Give examples with digits/ranges
15. 14 Marks
    Write short note on following.

    1. a)Digital storage oscilloscope
    2. b)Wein bridge
    How to answer

    • Explain principle, block diagram and working of digital storage oscilloscope
    • Explain sampling, memory and display operation
    • Explain Wein bridge circuit and balance condition
    • Mention applications of both