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ECE :: Electronic Devices and Circuits

  1. Assertion (A): In n-p-n transistor conduction is mainly due to electrons.

    Reason (R): In n type materials electrons are majority carriers.

  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

  3. The factor n in the equation for calculating current for a silicon diode is

  4. A.
    1
    B.
    2
    C.
    2.5
    D.
    2 for low levels of current and 1 for high levels of current

  5. An LED is

  6. A.
    an ohmic device
    B.
    a display device
    C.
    a voltage regulated device
    D.
    all of the above

  7. An enhancement mode MOSFET is on when the gate voltage is

  8. A.
    zero
    B.
    positive
    C.
    high
    D.
    more threshold value

  9. For the n-type semiconductor with n = NP and P = , the hole concentration will fall below the intrinsic value because some of the holes

  10. A.
    drop back to acceptor impurity states.
    B.
    drop to donor impurity states
    C.
    virtually leave the crystal
    D.
    recombine with the electrons.

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

  12. A.
    becomes zero
    B.
    abruptly decreases
    C.
    abruptly increases
    D.
    remains constant

  13. To avoid thermal runaway in the design of an analog circuit, the operating point of the BJT should be such that it satisfies the condition.

  14. A.
    VCE = VCC
    B.
    VCE VCC
    C.
    VCE VCC
    D.
    VCE ≤ 0.78 VCC

  15. For a MOS capacitor fabricated on a P-type semiconductor, strong inversion occurs when

  16. A.
    surface potential is equal to Fermi potential
    B.
    surface Potential is greater than Fermi potential
    C.
    surface potential is - ve and equal to Fermi potential in magnitude
    D.
    surface potential is + ve and equal to twice the Fermi potential

  17. The primary function of a clamper circuit is to

  18. A.
    suppress variations in signal voltage
    B.
    raise +ve half cycle to the signal
    C.
    Lower -ve half cycle of the signal
    D.
    introduce a dc level into an a.c. signal

  19. Breakdown in dielectric may be

  20. A.
    electrical breakdown
    B.
    thermal breakdown
    C.
    electrochemical breakdown
    D.
    any of the above