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ECE :: Electronic Devices and Circuits

  1. Assertion (A): Silicon is less sensitive to changes in temperature than germanium.

    Reason (R): It is more difficult to produce minority carriers in silicon than in germanium.

  2. 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

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  3. The number of protons in a silicon atom is

  4. A.
    32
    B.
    28
    C.
    14
    D.
    4

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  5. The emitter follower is widely used in electronic instrument because

  6. A.
    its voltage gain is less than unity
    B.
    its voltage gain is very high
    C.
    its O/P Impedance is low and input impedance is high
    D.
    its O/P Impedance is high and I/P impedance is low

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  7. A cascade amplifier stage is equivalent to

  8. A.
    a common emitter stage followed by a common stage
    B.
    a common base stage followed by an emitter follower
    C.
    an emitter follower stage followed by a common base stage
    D.
    a common base stage followed by a common emitter stage

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  9. An amplifier with resistive -ve feedback has two left poles in its open loop transfer function. The amplifier

  10. A.
    will always be unstable at high frequencies
    B.
    will be stable for all frequencies
    C.
    may be unstable, depending on the feedback factor
    D.
    will oscillate at low frequencies

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  11. Amplification of ultrasonic waves is possible in a piezoelectric semiconductor under applied electric field. The basic phenomenon involved is known as

  12. A.
    electrostriction
    B.
    acousto-optic interaction
    C.
    acousto-electric interaction
    D.
    stimulated Brillouin scattering

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  13. For a junction FET in the pinch off region, as the drain voltage is increased, the drain current

  14. A.
    becomes zero
    B.
    abruptly decrease
    C.
    abruptly increases
    D.
    remains constant

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  15. For a BJT, under the saturation region.

  16. A.
    IC = βIB
    B.
    IC > βIB
    C.
    IC is independent of other parameter
    D.
    IC < βIB

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  17. In which mode of BJT operation are both junctions reverse biased?

  18. A.
    Active
    B.
    Saturation
    C.
    Cut off
    D.
    Reverse active

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  19. In a junction transistor biased for operation at emitter current 'IE' and collector current 'IC' the transconductance 'gm' is.

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