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ECE :: Electronic Devices and Circuits

  1. Higher value of ripple factor indicates

  2. A.
    poor rectification
    B.
    ideal rectification
    C.
    r.m.s. value to peak value
    D.
    none of the above

  3. When a semi-conductor is doped, its electrical conductivity

  4. A.
    increases
    B.
    decreases in the direct ratio of the doped material
    C.
    decreases in the inverse ratio of the doped material
    D.
    remains unaltered

  5. The conduction band is

  6. A.
    same as forbidden energy gap
    B.
    generally located on the top of the crystal
    C.
    generally located on the bottom of the crystal
    D.
    a range of energies corresponding to the energies of the free electrons

  7. If an additional two diodes were used to connect the 1 kW load across a bridge rectifier circuits, utilizing the full secondary of the transformer, how much d.c. power could be delivered using a transformer with the rating of 105 VA?

  8. A.
    35 W
    B.
    60 W
    C.
    85 W
    D.
    100 W

  9. In an n channel JFET, VGS = VGS(off). Then

  10. A.
    ID is zero
    B.
    ID may be zero or positive
    C.
    ID is positive
    D.
    ID may be zero or negative

  11. In a bipolar transistor which current is smallest

  12. A.
    collector current
    B.
    base current
    C.
    emitter current
    D.
    any of the three currents

  13. With increasing temperature, the electrical conductivity of metals

  14. A.
    increases
    B.
    decreases
    C.
    increases first and then decreases
    D.
    remains unaffected

  15. The reverse saturation current in a semiconductor diode consists of

  16. A.
    avalanche current
    B.
    zener current
    C.
    minority carrier current
    D.
    minority carrier current and surface leakage current

  17. The current gain of a transistor is the ratio of

  18. A.
    emitter current to base current
    B.
    emitter current to collector current
    C.
    collector current to base current
    D.
    collector current to emitter current

  19. If a sample of Ge and a sample of Si have the same impurity density are kept at room temperature

  20. A.
    both will have equal value of resistivity
    B.
    both will have equal - ve of resistivity
    C.
    resistivity of germanium will be higher than that of silicon
    D.
    resistivity of silicon will be higher than of Ge