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ECE :: Electronic Devices and Circuits

  1. Typical value of reverse current in a semiconductor diode is

  2. A.
    1 A
    B.
    0.1 A
    C.
    1 μA
    D.
    0.1 μA

  3. Which of the following element has four valence electrons?

  4. A.
    Silicon
    B.
    Germanium
    C.
    Both (a) and (b) above
    D.
    None of the above

  5. In a transistor operating in forward active mode

  6. A.
    depletion layer between emitter and base is thin and that between base and collector is also thin
    B.
    both depletion regions are thick
    C.
    depletion layer between emitter and base is thin and that between base and collector is thick
    D.
    depletion layer between emitter and base is thick and that between base and collector is thin

  7. In standard TTL, the 'totem pole' stage refers to

  8. A.
    the multi-emitter I/P stage
    B.
    phase splitter
    C.
    the O/P buffer
    D.
    open collector O/P stage

  9. In p type semiconductor, the hole concentration

  10. A.
    is nearly equal to density of acceptor atoms
    B.
    is much greater than density of acceptor atoms
    C.
    is much less than density of acceptor atoms
    D.
    may be equal to or more or less than density of acceptor atoms

  11. If 100 V is the peak voltage across the secondary of the transformer in a half-wave rectifier (without any filter circuit), then the maximum voltage on the reverse-biased diode is

  12. A.
    200 V
    B.
    141.4 V
    C.
    100 V
    D.
    86 V

  13. The O/P Power of a power amplifier is several times its input power. It is possible because

  14. A.
    power amplifier introduces a -ve resistance
    B.
    there is +ve feed back in the circuit
    C.
    step up transformer is use in the circuit
    D.
    power amplifier converts a part of I/P d.c. power into a.c. power

  15. In p type semiconductor holes are majority carriers.

  16. A.
    True
    B.
    False

  17. Due to the formation of Schottky defects the density of the crystal

  18. A.
    increases slightly
    B.
    increases appreciably
    C.
    decreases slightly
    D.
    decreases appreciably

  19. The band gap of silicon at 300K is

  20. A.
    1.36 eV
    B.
    1.10 eV
    C.
    0.80 eV
    D.
    0.67 eV