Electronics - Introduction To Semiconductor Theory

49 Questions

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Semiconductor Quizzes & Trivia

This includes semiconductor theory and diodes.


Questions and Answers
  • 1. 
    Every known element has
    • A. 

      The same type of atoms

    • B. 

      the same number if atoms

    • C. 

      A unique type of atom

    • D. 

      Several different types of atoms

  • 2. 
    An atom consists of
    • A. 

      One nucleus and only one electron

    • B. 

      One nucleus and one or more electrons

    • C. 

      Protons, electrons, and neutrons

    • D. 

      Answers (b) and (c)

  • 3. 
    The nucleus of an atom is made up of
    • A. 

      Protons and neutrons

    • B. 

      Electrons

    • C. 

      Electrons and protons

    • D. 

      Electrons and neutrons

  • 4. 
    The atomic number of silicon is
    • A. 

      8

    • B. 

      2

    • C. 

      4

    • D. 

      14

  • 5. 
    The atomic number of germanium is
    • A. 

      8

    • B. 

      2

    • C. 

      4

    • D. 

      32

  • 6. 
    The valence shell in a silicon atom has the number designation of
    • A. 

      0

    • B. 

      1

    • C. 

      2

    • D. 

      3

  • 7. 
    Valence electrons are
    • A. 

      In the closest orbit to the nucleus

    • B. 

      In the most distant orbit from the nucleus

    • C. 

      In various orbits around the nucleus

    • D. 

      Not associated with a particular atom

  • 8. 
    A positive ion is formed when
    • A. 

      A valence electron breaks away from the atom

    • B. 

      there are more holes than electrons in the outer orbit

    • C. 

      Two atoms bond together

    • D. 

      An atom gains an extra valence electron

  • 9. 
    The most widely used semiconductive material in electronic devices is
    • A. 

      Germanium

    • B. 

      Carbon

    • C. 

      Copper

    • D. 

      Silicon

  • 10. 
    The energy band in which free electrons exist is the  
    • A. 

      First band

    • B. 

      Second band

    • C. 

      Conduction band

    • D. 

      Valence band

  • 11. 
    Electron-hole pairs are produced by
    • A. 

      Recombination

    • B. 

      Thermal energy

    • C. 

      Ionization

    • D. 

      Doping

  • 12. 
    Recombination is when
    • A. 

      An electron falls into a hole

    • B. 

      A positive and a negative ion bond together

    • C. 

      A valence electron becomes a conduction electron

    • D. 

      A crystal is formed

  • 13. 
    In a semiconductor crystal, the atoms are held together by
    • A. 

      The interaction of valence electrons

    • B. 

      Forces of attraction

    • C. 

      Covalent bonds

    • D. 

      Answers (A), (B), and (C)

  • 14. 
    Each atom  in a silicon crystal has
    • A. 

      Four valence electrons

    • B. 

      Four conduction electrons

    • C. 

      Eight valence electrons, four of its own and four shared

    • D. 

      No valence electrons because all are shared with other atoms

  • 15. 
    The current in a semiconductor is produced by
    • A. 

      Electron only

    • B. 

      Holes only

    • C. 

      Negative ions

    • D. 

      Both electrons and holes

  • 16. 
      In an intrinsic semiconductor,
    • A. 

      There are no free electrons

    • B. 

      The free electrons are thermally produced

    • C. 

      There are only holes

    • D. 

      There are many electrons as there are holes

    • E. 

      Answers (B) and (D)

  • 17. 
    The difference between an insulator and a semiconductor is
    • A. 

      A wider energy gap between the valence band and the conduction band

    • B. 

      The number of free electrons

    • C. 

      The atomic structure

    • D. 

      Answers (A), (B), and (C)

  • 18. 
      The process of adding an impurity to an intrinsic semiconductor is called
    • A. 

      Doping

    • B. 

      Recombination

    • C. 

      Atomic modification

    • D. 

      Ionization

  • 19. 
    The trivalent impurity is added to silicon to create
    • A. 

      Germanium

    • B. 

      A p-type semiconductor

    • C. 

      An n-type semiconductor

    • D. 

      A depletion region

  • 20. 
    The purpose of pentavalent impurity is to
    • A. 

      Reduce the conductivity of silicon

    • B. 

      Increase the number of holes

    • C. 

      Increase the number of free electrons

    • D. 

      Create minority carriers

  • 21. 
    The majority carriers in an n-type semiconductor are
    • A. 

      Holes

    • B. 

      Valence electrons

    • C. 

      Conduction electrons

    • D. 

      Protons

  • 22. 
    Holes in an n-type semiconductor are
    • A. 

      Minority carriers that are thermally produced

    • B. 

      Minority carriers that are produced by doping

    • C. 

      Majority carriers that are thermally produced

    • D. 

      Majority carriers that are produced by doping

  • 23. 
    A pn junction is formed by
    • A. 

      The recombination of electrons and holes

    • B. 

      Ionization

    • C. 

      The boundary of a p-type and an n-type material

    • D. 

      The collision of a proton and a neutron

  • 24. 
    The depletion region is created by
    • A. 

      Ionization

    • B. 

      Diffusion

    • C. 

      Recombinations

    • D. 

      Answers (A), (B), and (C)

  • 25. 
    The depletion region consists of
    • A. 

      Nothing but minority carriers

    • B. 

      Positive and negative ions

    • C. 

      No majority carriers

    • D. 

      Answers (B) and (C)

  • 26. 
    The term bias means
    • A. 

      The ratio of majority carriers to minority carriers

    • B. 

      The amount of current across the diode

    • C. 

      A dc voltage is applied to control the operation of a device

    • D. 

      Neither (A), (B), nor (C)

  • 27. 
    To forward-bias a diode,
    • A. 

      An external voltage is applied that is positive at the anode and negative at the cathode

    • B. 

      An external voltage is applied that is negative at the anode and positive at the cathode

    • C. 

      An external voltage is applied that is positive at the p region and negative at the n region

    • D. 

      Answers (A) and (C)

  • 28. 
    When a diode is forward-biased,
    • A. 

      The only current is hole current

    • B. 

      The only current is electron current

    • C. 

      The only current is produced by the majority carriers

    • D. 

      The current is produced by both holes and electrons

  • 29. 
    Although current is blocked in reverse bias,
    • A. 

      There is some current due to majority carriers

    • B. 

      There is a very small current due to minority carriers

    • C. 

      There is an avalanche current

  • 30. 
    For a silicon diode, the value of the forward-bias voltage typically
    • A. 

      Must be greater than 0.3 V

    • B. 

      Must be greater than 0.7 V

    • C. 

      Depends on the width of the depletion region

    • D. 

      Depends on the concentration of majority carriers

  • 31. 
    When forward-bias, a diode
    • A. 

      Blocks current

    • B. 

      Conducts current

    • C. 

      Has high resistance

    • D. 

      Drops a large voltage

  • 32. 
    When a voltmeter is placed across a forward-biased diode, it will read a voltage approximately equal to
    • A. 

      The bias battery voltage

    • B. 

      0 V

    • C. 

      The diode barrier potential

    • D. 

      The total circuit voltage

  • 33. 
    A silicon diode is in series with a 1.0kW resistor and a 5 V battery. If the anode is connected to the positve battery terminal, the cathode voltage with respect to the negative battery terminal is
    • A. 

      0.7 V

    • B. 

      0.3 V

    • C. 

      5.7 V

    • D. 

      4.3 V

  • 34. 
    The postive lead of an ohmmeter is connected to the anode of a diode and the negative lead is connected to the cathode. The diode is
    • A. 

      Reversed-bias

    • B. 

      Open

    • C. 

      Forward-biased

    • D. 

      Faulty

    • E. 

      Answers (B) and (D)

  • 35. 
    Approximates real diode with a battery, a resistance, and an ideal diode
    • A. 

      Simplified model

    • B. 

      Non ideal device

    • C. 

      Ideal device

    • D. 

      Piecewise – linear model

  • 36. 
    What type of bias opposes the pn junction barrier?
    • A. 

      No bias

    • B. 

      Direct bias

    • C. 

      Reverse bias

    • D. 

      Forward bias

  • 37. 
    Semi-conductors which are doped with either N or P types of impurities are called _________.
    • A. 

      Intrinsic

    • B. 

      Extrinsic

    • C. 

      P-type

    • D. 

      N-type

  • 38. 
     How many junctions are there in a semiconductor diode?
    • A. 

      Two

    • B. 

      None

    • C. 

      One

    • D. 

      Four

  • 39. 
    In electricity, electric charge refers to __________.
    • A. 

      Protons

    • B. 

      Electrons

    • C. 

      Neutrons

    • D. 

      Atoms

  • 40. 
    Term used to described sudden reverse conduction of an electronic component caused by excess reverse voltage across the device.
    • A. 

      Cut-off

    • B. 

      Avalanched

    • C. 

      Saturation

    • D. 

      Reversion

  • 41. 
    Outer shell of an atom is _______
    • A. 

      Electron

    • B. 

      Proton

    • C. 

      Depletion

    • D. 

      Valence

  • 42. 
    A circuit that adds a dc level to an ac voltage using a diode and a capacitor.
    • A. 

      Clamper

    • B. 

      Filter

    • C. 

      Full-wave rectifier

    • D. 

      Half-wave rectifier

  • 43. 
    A capacitor in a power supply used to reduce the variation of the output voltage from a rectifier.
    • A. 

      Clamper

    • B. 

      Filter

    • C. 

      Limiter

    • D. 

      Regulator

  • 44. 
    The change in output voltage of a regulator for a given change in input voltage normally expressed as a percentage.
    • A. 

      Line regulation

    • B. 

      Load regulation

    • C. 

      Ripple voltage

    • D. 

      Surge resistance

  • 45. 
    Load regulation is determined by __________.
    • A. 

      Changes in load current and input voltage

    • B. 

      Changes in load current and output voltage

    • C. 

      Changes in load resistance and input voltage

    • D. 

      Changes in zener current and load current

  • 46. 
    If one of the diodes in a bridge full-wave rectifier opens, the output is _______.
    • A. 

      0 V

    • B. 

      One-fourth the amplitude of the input voltage

    • C. 

      A half-wave rectified voltage

    • D. 

      A 120 Hz voltage

  • 47. 
    A 10V peak-to-peak sinusoidal voltage is applied across a silicon diode and series resistor. The maximum voltage across the diode is ________.
    • A. 

      9.3 V

    • B. 

      5 V

    • C. 

      0.7 V

    • D. 

      10 V

    • E. 

      4.3 V

  • 48. 
    If the load resistance of a capacitor-filtered full-wave rectifier is reduced, the ripple voltage _________.
    • A. 

      Increases

    • B. 

      Decreases

    • C. 

      Is not affected

    • D. 

      Has a different frequency

  • 49. 
    When a 60 Hz sinusoidal voltage is applied to the input of a full-wave rectifier, the output frequency is ______.
    • A. 

      120 Hz

    • B. 

      60 Hz

    • C. 

      240 Hz

    • D. 

      0 Hz