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EXAM 2

  1. (25 points)

    The npn transistor used in this problem is a very poor one with tex2html_wrap_inline530 and tex2html_wrap_inline532 . As usual assume tex2html_wrap_inline237 . Circuit values are given as tex2html_wrap_inline536 , tex2html_wrap_inline538 , tex2html_wrap_inline540 , tex2html_wrap_inline542 , and tex2html_wrap_inline544 .

    The input is given by the sum of a DC tex2html_wrap_inline546 and an AC tex2html_wrap_inline548 . Answer the following questions. Show all work.

    1. Compute the DC operating point. Show all of your work. tex2html_wrap_inline257 (DC)

      tex2html_wrap_inline261 (DC)

      tex2html_wrap_inline259 (DC)

      tex2html_wrap_inline255 (DC)

      tex2html_wrap_inline251 (DC)

      tex2html_wrap_inline253 (DC)

      tex2html_wrap644

    2. (5 points) Compute the small signal gain of this circuit.
       
      tex2html_wrap_inline342 (expression)
       
      tex2html_wrap_inline342 (number)

    3. (5 points) What is the maximum and minimum output voltages (total signal) if the small signal input is given by tex2html_wrap_inline566 ? Be sure to consider both the AC and DC components for all signals.

    4. (5 points) For what range of output voltages (-15V to 15V) is the transistor in its active region?

  2. (25 points)

    The npn transistor used in this problem has tex2html_wrap_inline530 and tex2html_wrap_inline570 . As usual assume tex2html_wrap_inline237 .

    Circuit values are given as tex2html_wrap_inline574 , tex2html_wrap_inline576 , tex2html_wrap_inline578 , tex2html_wrap_inline540 , tex2html_wrap_inline582 , and tex2html_wrap_inline544 . Answer the following questions. Show all work.

    1. (10 points) Compute the DC operating point. tex2html_wrap_inline251 (DC)

      tex2html_wrap_inline253 (DC)

      tex2html_wrap_inline255 (DC)

      tex2html_wrap_inline259 (DC)

      tex2html_wrap_inline261 (DC)

      tex2html_wrap_inline257 (DC)

      tex2html_wrap652

    2. (5 points) Compute the small signal parameters:
       
      tex2html_wrap_inline390
       
      tex2html_wrap_inline340

    3. (10 points) Compute the small signal gain of this circuit.
       
      tex2html_wrap_inline342 (expression)
       
      tex2html_wrap_inline342 (number)

  3. (25 points)

    tex2html_wrap646

    The MOSFETs used in this problem have tex2html_wrap_inline606 , infinite Early voltage, and a threshold voltage of tex2html_wrap_inline608 . Component values are given by: tex2html_wrap_inline610 , tex2html_wrap_inline612 , and tex2html_wrap_inline614 . Ignore the body effect.

    1. (10 points) Write an expression for the small signal gain tex2html_wrap_inline409 .

    2. (10 points) Choose values for tex2html_wrap_inline618 , tex2html_wrap_inline620 , and the DC value of tex2html_wrap_inline622 such that the magnitude of the small signal gain tex2html_wrap_inline624 is ten (to within a few percent) . Explain your reasoning. Make sure that the values you choose bias the MOSFETs in the appropriate region. Note that there are many possible correct answers.
    3. (5 points) Choose values for tex2html_wrap_inline303 and tex2html_wrap_inline305 such that the DC value of tex2html_wrap_inline622 is as you specified in part (c).

      (use this page for extra work if necessary)

  4. (25 points) Short Answer.

    tex2html_wrap648

    The curves above were measured from either a MOSFET or a bipolar transistor.

    1. (5 points) Which device were the measurements taken from? Label the current and voltage axes appropriately. You must explain your answer, otherwise no credit will be given.
    2. (5 points) Estimate the Early voltage of this device. Explain.

    3. (5 points) Compute the DC voltage V assuming tex2html_wrap_inline632 , tex2html_wrap_inline374 and tex2html_wrap_inline636 .

      tex2html_wrap650

    4. (5 points) Compute the DC voltage V assuming tex2html_wrap_inline632 , tex2html_wrap_inline374 and tex2html_wrap_inline636 .

      tex2html_wrap652

    5. (5 points) Briefly describe the major differences between biasing MOSFETs for discrete vs. integrated circuit amplifier design.


next up previous
Next: EEL3304: OLD EXAMS Up: EEL3304: EXAMS Previous: EXAM 1

Dr John Harris
Wed Dec 10 08:15:23 EST 1997