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ECE :: Exam Questions Paper

  1. In the circuit shown below, the op-amp is ideal, the transistor has VBE = 0.6 V and β = 150. Decide whether the feedback in the circuit is positive or negative and determine the voltage V at the output of the op-amp

  2. A.
    Positive feedback, V = 10 V
    B.
    Positive feedback, V = 0 V
    C.
    Negative feedback, V = 5 V
    D.
    Negative feedback, V = 2 V

  3. Which of the following addressing modes is used in the instruction PUSH B?

  4. A.
    Direct
    B.
    Register
    C.
    Register Indirect
    D.
    Immediate

  5. Consider a silicon p-n junction at room temperature having the following parameters:
    Doping on the n-side = 1 x 1017 cm-3
    Depletion width on the n-side = 0.1 μm
    Depletion width on the p-side = 1.0 μm
    Intrinsic carrier concentration = 1.4 x 1014F. cm-1.
    Thermal voltage = 26mV
    Permittivity of free space = 8.85 x 10-14F. cm-1.
    Dielectric constant of silicon = 12. The peak electric field in the device is

  6. A.
    0.15 MV.com-1, directed from p-region to n-region
    B.
    0.15 MV.com-1, directed from n-region to p-region
    C.
    1.80 MV.com-1, directed from p-region to n-region
    D.
    1.80 MV.com-1, directed from n-region to p-region

  7. A single turn loop is situated in air, with a uniform magnetic field normal to its plane. The area of the loop is 5 m2 and the rate of change of flux density is 2 Wb/m2/s. What is the emf appearing at the terminals of the loop?

  8. A.
    -5 V
    B.
    -2 V
    C.
    -0.4 V
    D.
    0 V

  9. A compensated wattmeter has its reading corrected for error due to which one of the following parameters?

  10. A.
    Frequency
    B.
    Friction
    C.
    Power consumed in current coil
    D.
    Power consumed in pressure coil

  11. Personal computer cannot be used for which one of the following?

  12. A.
    Game playing
    B.
    Weather forecasting
    C.
    Office Automation
    D.
    Home computing

  13. Which of the following output configurations are available in a TTL gate?

    1. Open collector output
    2. Totem pole output
    3. Tristate output
    Select the correct answer from the codes given below:

  14. A.
    1 only
    B.
    1 and 2 only
    C.
    2 and 3 only
    D.
    1, 2 and 3

  15. Which of the following be true for a CE transistor amplifier if the emitter resistor value is made equal to zero?

    1. Its gain will increase
    2. Its stability will increase
    3. Its gain will decrease
    4. Its stability will decrease
    Select the correct answer from the codes given below

  16. A.
    1 and 2
    B.
    2 and 3
    C.
    3 and 4
    D.
    1 and 4

  17. The feedback control system shown in figure is stable.

  18. A.
    for all K ≥ 0
    B.
    only if K ≥ 1
    C.
    only if 0 ≤ K < 1
    D.
    only if -1 ≤ K < 1