EE3300/EE5300 Electronics Applications
Week 1 Tutorial

Written by A/Prof Bronson Philippa
College of Science and Engineering, James Cook University
Last updated 31 January 2025

Workshop warm-up

  • From this week’s notes, what material were you most comfortable with? What material were you the least comfortable with?
  • Is there anything that you’d like clarification on?

Workshop discussion question 1

Complete AoE Exercise 1.44 (p. 67): Design a 10x oscilloscope probe, i.e. a probe that raises the input impedance of the oscilloscope by a factor of 10. (Solution)

Discussion prompts:

  • In what circumstances would you prefer a 1x probe over a 10x probe and vice versa?
  • Notice from the design solution that the capacitance in the probe tip depends upon the capacitance of the cable. What happens if the probe tip capacitance isn’t correct? (Have you ever noticed the adjustment screw on your oscilloscope probe?)

Workshop discussion question 2

How to choose a transistor for a given application? Study AoE Table 2.1 (p. 74) and discuss the following points:

  • What is the meaning of each of the columns in the table?
  • In practicals, we will often use 2N3904/2N3906 transistors for small signal applications. What are the strengths and weaknesses of these transistors compared to the BC547/BC557?
  • Recommend a transistor for high frequency applications. Based on this table, what penalty is paid when selecting a part with a high cutoff frequency?

Tutorial questions

BJTs

  1. AoE Exercise 2.1 (p. 76). Assume a red LED and use the IV characteristic in Figure 2.8. (Solution)

  2. AoE Exercise 2.4 (p. 80). The question is asking you to examine the impedance seen looking into the emitter. Hint: use the small signal model and consider the formal definition of output impedance as introduced in this week’s notes. (Solution)

  3. (1) Prove that the current gain of a Darlington pair is

    Neglect the Early effect.

    (2) Show that the input impedance (looking into the base) of the Darlington pair is

    Assume that the collector and emitter are at fixed voltages and neglect the Early effect.

    (Solution)

Field effect transistors

  1. AoE Exercise 3.1 (p. 144). (Solution)

  2. AoE Exercise 3.4 (p. 165). (Solution)

Current mirrors

Figure 1
Figure 1:

BJT current mirror.

Zoom:

  1. Consider the circuit shown in Figure 1. Use the Ebers-Moll model to prove that . (Solution)

  2. Modify the circuit in Figure 1 to double the current, i.e. propose a design with . Hint: transistors are cheap. (Solution)

  3. Modify the circuit in Figure 1 to use MOSFETs instead of BJTs. Prove that the circuit still works as a current mirror. (Solution)

Differential circuits and symmetry

Razavi Chapter 10 problems. (JCU login required)

  1. Razavi Exercise 10.3. (Solution)

  2. Repeat the previous question for the bipolar differential pair (Figure 2). (Solution)

    Figure 2
    Figure 2:

    BJT differential pair.

    Zoom:

  3. Razavi Exercise 10.12. (Solution)

  4. Razavi Exercise 10.18. (Solution)

  5. Razavi Exercise 10.30. (Solution)

  6. Razavi Exercise 10.31. (Solution)

  7. Razavi Exercise 10.33. (Solution)

Additional tutorial questions

The questions below are considered to be of lower priority. Questions from this list are less likely to appear in the quizzes.

BJTs

These questions will help you practice using the Ebers-Moll model.

Razavi Chapter 4 problems (JCU login required)

  1. Razavi Exercise 4.5. (Solution)

  2. Razavi Exercise 4.7. (Solution for 4.7 and 4.8)

  3. Razavi Exercise 4.8.

  4. Razavi Exercise 4.14. (Solution)

  5. Razavi Exercise 4.19. (Solution)

  6. Razavi Exercise 4.21. (Solution)

  7. Razavi Exercise 4.30. (Solution)

The questions below are about design of amplifiers. Although we didn’t focus on amplifier topologies in the notes, it’s assumed that you recall the basic amplifier configurations from your previous study of electronics. There are some revision notes available if you need to refresh your memory.

Razavi Chapter 5 problems (JCU login required)

  1. Razavi Exercise 5.74. (Solution)

  2. Razavi Exercise 5.75. (Solution)

  3. Razavi Exercise 5.80. (Solution)

  4. Razavi Exercise 5.83. (Solution)

  5. Razavi Exercise 5.88. (Solution)

MOSFETs

The questions below from Razavi assume integrated circuits (i.e. MOSFETs wherein the designer may adjust the aspect ratio , where is the channel width and is the channel length).

Razavi Chapter 6 problems (JCU login required)

  1. Razavi Exercise 6.11. (Solution)

  2. Razavi Exercise 6.20. (Solution)

  3. Razavi Exercise 6.24. (Solution)

  4. Razavi Exercise 6.26. (Solution)

Razavi Chapter 7 problems (JCU login required)

  1. Razavi Exercise 7.1. (Solution)

  2. Razavi Exercise 7.2. (Solution)

  3. Razavi Exercise 7.10. (Solution)

  4. Razavi Exercise 7.15. (Solution)

Below are some design questions. There are some revision notes available if you need to refresh your memory of MOSFET amplifier topologies.

  1. Razavi Exercise 7.61. (Solution)

  2. Razavi Exercise 7.67. (Solution)

  3. Razavi Exercise 7.68. (Solution)