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ECE :: Electronic Devices and Circuits

  1. The maximum rectification efficiency in case of full wave rectifier is

  2. A.
    100%
    B.
    81.2%
    C.
    66.6%
    D.
    40.6%

  3. For a full wave bridge rectifier supplied with 50 Hz a.c., the lowest ripple frequency will be

  4. A.
    50 Hz
    B.
    100 Hz
    C.
    200 Hz
    D.
    400 Hz

  5. When an electron rises through a potential of 100 V it will acquired an energy of

  6. A.
    100 eV
    B.
    100 Joules
    C.
    100 ergs
    D.
    100 x 10-6 Newtons

  7. Which one of the following gain equations is correct for a MOSFET common-source amplifier?
    (gm is mutual conductance, and RD is load resistance at the drain)

  8. A.
    AV = gm/(1 - RD)
    B.
    AV = gm/RD
    C.
    AV = gm/(1 + RD)
    D.
    AV = RD/gm

  9. If 1 kVA transformer is used for all of the following rectifiers, the d.c. power availability will be least in case of

  10. A.
    half wave rectifier
    B.
    full wave rectifier
    C.
    bridge rectifier
    D.
    three phase full wave rectifier

  11. Which of the following is the ferric electric material?

  12. A.
    Rochelle salt
    B.
    Barium titanate
    C.
    Potassium dihydrogen phosphate
    D.
    All of the above

  13. The amount of time between the creation and disappearance of a hole in an intrinsic semiconductor material is called

  14. A.
    life cycle
    B.
    recombination time
    C.
    life time
    D.
    half life

  15. In photo electric emission, the threshold frequency f0, work function Uw, and Planck's constant h are related as

  16. A.
    B.
    C.
    f0 = (Uw)(h)2
    D.
    h = (Uw)(f0)

  17. In which n type device does p substrate extend upto silicon dioxide layer?

  18. A.
    JFET
    B.
    Depletion type MOSFET
    C.
    Enhancement type MOSFET
    D.
    Both (b) and (c)

  19. In a N-type semi-conductor, the concentration of minority carriers is mainly depends on

  20. A.
    the number of acceptor atoms
    B.
    the number of donor atoms
    C.
    the extent of doping
    D.
    the temperature of the material