Electronics Paper 2, May/June 2013  
Questions: 1 2 3 4 5, 6 &7 8 9 10 Main
General Comments

Question 1
  1.  Explain how a bipolar transistor is constructed.
  2.  State two applications of a transistor.
  3.  Draw and label the circuit symbol of a/an:
    1. npn transistor;
    2. pnp transistor.



    The expected answers were:

  1.  The construction of a bipolar junction transistor involves two PN junctions connected back-to-back in either the NPN or PNP configurations.
  2.  Application
    1. Switching circuits
    2. Amplifier circuits
    3. Logic circuits
    4. Oscillator circuits


      The question was on Bipolar transistors. It was quite unpopular with the candidates. The performance was poor.

      In part (a), a number of the candidates gave details of how the BJT is manufactured without mentioning the basic and desired fact. Part (b) was answered correctly by many while some lost marks in part (c) either because they did not indicate the arrows or mixed up the arrow directions, giving one for the other.

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