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ECE :: Electronic Devices and Circuits

  1. The resistivity of a semiconductor

  2. A.
    increases as the temperature increases
    B.
    decreases as the temperature increases
    C.
    remains constant even when temperature varies
    D.
    none of the above

  3. The voltage at which Avalanche occurs is known as

  4. A.
    cut in voltage
    B.
    barrier voltage
    C.
    breakdown voltage
    D.
    depletion voltage

  5. If the energy gap of a semiconductor is 1.1 eV, then it would be

  6. A.
    opaque to visible light
    B.
    transparent to visible light
    C.
    transparent to ultraviolet radiation
    D.
    transparent to infrared radiation

  7. In intrinsic semiconductor the increase in conductivity per degree increase in temperature is about

  8. A.
    2%
    B.
    6%
    C.
    15%
    D.
    25%

  9. The ripple factor for a bridge rectifier is

  10. A.
    0.406
    B.
    1.21
    C.
    1.11
    D.
    2.22

  11. Which of the following semi-conductor has forbidden energy gap less 1 eV?

  12. A.
    Sulphur
    B.
    Phosphorous
    C.
    Germanium
    D.
    Carbon

  13. In the vacuum diode equation ib = keb1.5, the current is

  14. A.
    temperature limited current
    B.
    space charge limited current
    C.
    any of the above
    D.
    none of the above

  15. Thermosetting polymers are

  16. A.
    injection moulded
    B.
    extruded
    C.
    cast moulded
    D.
    none of the above

  17. Which of these is used in seven segment display?

  18. A.
    PIN diode
    B.
    LED
    C.
    Photo diode
    D.
    Tunnel diode

  19. The current in a p-n junction diode with V volts applied in p region relative to n region (where I0 is reverse saturation current, m is ideality factor, k is Boltzmann's constant, T is absolute temp and q is charge on electron) is

  20. A.
    I0 (e-qV/mkT - 1)
    B.
    I0 e-qV/mkT
    C.
    I0 (eqV/mkT)
    D.
    I0 (eqV/mkT - 1)