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ECE :: Electronic Devices and Circuits

  1. A JFET operates in ohmic region when

  2. A.
    VGS = 0
    B.
    VGS is less than pinch off voltage
    C.
    VGS = is Positive
    D.
    VGS = VDS

  3. In CE connection, the leakage current of a transistor is about

  4. A.
    10 x 10-9 A
    B.
    5 x 10-6 A
    C.
    200 x 10-6 A
    D.
    5 x 10-3 A

  5. The early effect in a BJT is caused by

  6. A.
    fast turn on
    B.
    fast turn off
    C.
    large collector base reverse bias
    D.
    large emitter base forward bias

  7. In a common emitter BJT amplifier, the maximum usable supply voltage is limited by

  8. A.
    avalanche Beakdown of Base-Emitter junction
    B.
    collector emitter breakdown voltage with base open(βVCEO)
    C.
    collector emitter breakdown voltage with emitter open(βVCEO)
    D.
    zener break down voltage of the emitter base junction

  9. Assertion (A): In active region of CE output characteristics of BJT, collector current is nearly constant.

    Reason (R): Base current in CE connection is very small.

  10. A.
    Both A and R are true and R is correct explanation of A
    B.
    Both A and R are true but R is not a correct explanation of A
    C.
    A is true but R is false
    D.
    A is false but R is true

  11. The temperature of cathode is increased from 2500K to 2600K. The increase in thermionic emission current is about

  12. A.
    0.1%
    B.
    4%
    C.
    50%
    D.
    150%

  13. Consider the following statement: At finite temperature, magnetic dipoles in a material are randomly oriented giving low magnetization. When magnetic field H is applied, the magnetization?

    1. Increases with H
    2. Decreases with H
    3. Decreases with temp for constant H
    Which of the statement given above is/are correct?

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

  15. Ferrites have

  16. A.
    low copper loss
    B.
    low eddy current loss
    C.
    low resistivity
    D.
    higher specific gravity compared to iron

  17. Eg is the band gap, A is pre-factor, k is Boltzmann constant? Which one of the following is the remaining grade of paper used in paper capacitor, besides the other two grade of paper-low and extra low loss?

  18. A.
    Strong dielectric
    B.
    Regular
    C.
    Rough
    D.
    High loss

  19. Barkhausen criterion of oscillation is

  20. A.
    Aβ > 1
    B.
    Aβ = 1
    C.
    Aβ = < 1
    D.
    Aβ ≤ 1