Electronic Devices

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Electronic Devices
2011-02-05 16:20:52

Intro to semiconductors
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  1. Anode
    The P region of a diode which is positive
  2. Atom
    The smallest particle of an element that possesses the characteristics of that element
  3. Barrier potential
    the amount of energy required to produce full conduction across the PN junction in forward bias
  4. Bias
    The application of a DC voltage to a diode to make it either conduct or block current
  5. Cathode
    The N region of the diode which is negative
  6. Crystal
    A solid material in which the atom are arranged in a symmetrical pattern
  7. Diode
    A semiconductor device with a single PN junction that conducts current in only one direction.
  8. Doping
    The process of imparting impurities to an intrinsic (pure) semiconductive material in order to control its conduction characteristics
  9. Forward Bias
    The condition in which a diode conducts current
  10. Free Electron
    An electron that has aquired enough energy to break away from the valence band of the parent atom
  11. Hole
    The absence of an electron in the valence band of an atom
  12. Ionization (positive ion, negative ion)
    The removal or addition of an electron from or to a nuetral atom so that the resulting atom has a positive or negative charge.
  13. PN junction
    The boundry between two different types of semiconductive materials
  14. Reverse Bias
    The condition in which a diode prevents current. ( action like an open switch)
  15. Semiconductor material
    Silicon, Germanium and carbon
  16. V-I characteristic
    A curve showing the relationship of a diode voltage and current
  17. N-type impurity atom
    Pentavalent atoms which have five valence electrons
  18. P-type impurity atom
    Trivalent atoms which have three valence electrons
  19. Covalent bond
    is created by the sharing of valence electrons
  20. Electron current
    When a voltage is applied across the semiconductor the free electrons move towars the the positive end (to the right)and form the current
  21. Hole current
    This occurs as valence electrons move from hole to hole (left to right)creating a movement of holes from right to left
  22. The majority carriers in N-type semiconductors
    free electrons
  23. The minority carriers in N-type semiconductors
  24. The majority carriers in P-type semiconductors
  25. The minority carriers in P-type semiconductors
    free electrons
  26. How a PN junction is formed
    when part of a material is doped N-type and part is doped P-type. A depletion region forms by ionization and starts at the junction that is devoid of any majority carriers
  27. The barrier potential for a silicon diode
  28. The barrier potential for a germanium diode
  29. What does the dig. multimeter display when the diode is in reverse bias but working properly?
  30. What does the dig. multimeter display when the diode is working in forward bias?
    0.7V or 0.3V
  31. Reverse breakdown voltage for a diode
    greater than 50V
  32. What does the dig. multimeter display when the diode is open?
    OL in forward and reverse bias
  33. What does the dig. multimeter display when the diode is shorted?
    0V in forward and reverse bias
  34. IF= forward current for ideal diode model
    • IF= VBias
    • ......RLimit
  35. IF= Forward current for practical diode model
    • IF= Vbias-VF
    • ..........RLimit
  36. The ideal diode model
    Used for troubleshooting and does not give exact voltage or current. It is represented as a switch. Forward bias =closed switch. Reverse bias= open switch.
  37. The practical diode model
    includes barrier potentail which is written as VF = 0.7V. VBias is the Voltage that is applied to the circuit