HIS HOMEPAGE contains information about the second-year subject Electronic Circuits offered in the first semester of 2007/2008. It tells you everything about this course, including its aims, syllabus, philosophy and operation.

• What is this course for?
• What you will learn: A criterion-based viewpoint
• Lecture and tutorial schedule
• Assignments and laboratory sessions
• Assessment
• Student consultation hours
• Supplementary materials
• Final advice
• References

Covering the foundation of electronic circuits, this course is almost always taught as a compulsory subject in universities. If you take a look at websites of other electrical or electronic engineering (EE) curricula around the world, you won't be surprised that what you will be doing are usually regarded as some of the most basic elements in a EE curriculum. In fact, what you are going to learn about is the essential concepts for analysis and design of electronic circuits, e.g., transistor amplifiers, current mirrors, differential amplifiers, operational amplifier design, frequency responses of amplifiers, feedback amplifiers, etc., which are certainly never optional materials in EE curricula. Having said this, I hope I am putting you on a positive perspective of taking such a course. In fact, I find no exaggeration in saying that no one should claim to be an electronic engineer without thorough understanding of the concepts taught in this subject.

1. Getting started (1 week):

   As far as I understand, ENG238 has discussed the basic techniques of biasing a transistor and getting it to work as an amplifier. I would assume that you also know a bit of small-signal models, to the point where analysis can be carried out to derive some simple but vital relationships, e.g., gain, input and output impedances. I'll spend a little bit of time at the beginning to refresh these basic concepts before we begin looking into new concepts.

2. Essential building blocks (3 weeks):

   The first part of this course is a continuation of the material you learnt in year-1 ENG238 regarding some basic transistor circuit configurations. I will discuss several important analog circuit building blocks which you will frequently encounter in practical design of electronic circuits. These include mirrors, differential amplifiers and output stages (also called power amplifiers). Our discussions will be focused on the basic constructions and the operating principles of these building blocks. Later on, you will find these building blocks extremely useful when you come to study how a complete practical amplifier is constructed.

3. Operational amplifier design (2 weeks):

   I am sure you all know what an op-amp is and what it is supposed to do. Probably, in year-1 ENG238, you treated the op-amp as an ideal element, having infinite input resistance and infinite voltage gain. Well, these ideal features are still important in helping us understand how op-amp circuits work. In this course, we will uncover this magical "triangle" and examine the various circuit components in a typical op-amp. Further, we will also study the practical "non-ideal" behaviours of op-amps that limit their performance, and the ways to deal with these non-idealities.

4. Frequency response of transistor amplifiers (2 weeks):

   Up to BE, your understanding of transistor amplifiers is that they provide amplification. The assumption was that parasitics were insignificant for signals being of low frequency. In this course, I will take you further up the frequency axis. Essentially, we will re-examine the transistor amplifiers in the light of the presence of parasitics. We will focus on the dominating effect of frequency roll-off due to what is usually known as the Miller effect. Typically we will see that the gain diminishes as the frequency increases. Our analysis will formally find the exact frequency point where the gain begins to fall.

5. Feedback amplifiers and oscillators (4 weeks):

   Feedback is an important technique to stabilize the gain of amplifier, as well as to modify the input and output resistances, making the amplifier more desirable. But feedback may cause oscillation too. Here, we will formally study the feedback mechanism and the various transistor feedback amplifier configurations. I will emphasize practical analysis where loading effects must be well accounted for. The tool I use is two-port network modeling. I will discuss the various problems of feedback, e.g., stability, gain reduction, etc. Moreover, there are also applications where oscillation can be fruitfully used. We will therefore extend our feedback concepts to the design of oscillators where oscillation is deliberately created.

6. Final revision (1 week):

   The last lecture or tutorial will be a revisional session. I will summarize the main points of the material I have covered, and give further details about the format of the final examimation.

This year, the weekly 2-hour lecture is scheduled on every Thursday, from 4:30 pm to 6:30 pm, at Room HJ302. Moreover, two tutorial sessions are scheduled on Wednesday (10:30am-11:30am, Room BC302) and Thursday (12:30pm-1:30pm, Room BC302). You are required to attend only one 1-hour tutorial, depending on your own group's time-table.

Tentative Dates	Lecture topics	Notes
6 September	Revision lecture No tutorial in this week.	Part 1 of 2 (124 KB) Part 2 of 2 (152 KB)
13 September	Revision lecture Tutorials begin this week.
20 September	Lectures on 20 September will be moved to 19 September, 2:30pm-4:30pm in Room FJ304. All tutorials will run as usual.
27 September	Lectures on 27 September will be cancelled. All tutorials will run as usual.
19 September, 4-11 October	Essential building blocks Part 1: mirrors and active loads Part 2: differential amplifiers Part 3: output stages (power amplifiers)	Part 1 of 3 (176 KB) Part 2 of 3 (292 KB) Part 3 of 3 (248 KB)
18-25 October	Operational amplifier design	(584 KB)
1 November	Mid-Semester TEST All tutorials suspended for this week	Test paper and Solution
Special tutorial	Review on poles and zeros, and Bode Plots	Refer to Chapter 8 of Tse's textbook Linear Circuit Analysis
8-15 November	Frequency response of transistor amplifiers	(128 KB)
22-29 November	Feedback amplifiers and oscillators	(542 KB)

I will hand out a problem set which contains practice problems related to the course. Submission of selected problems will be required, as assignments. You must try to work out solutions all on your own. During the tutorials, I will explain some of the problems related to the assignments. Remember assignments do count towards your continual assessments.

Problem set for this course: (1.2 MB)

Assignment 1: Questions 2, 3 and 5 of problem set. Hand-in: 18 October 2007. Download solutions here Assignment 2: Questions 8 and 9 of problem set. Hand-in: 15 November 2007. Solution to Problem 8 and Solution to Problem 9 Assignment 3: Questions 11 and 14 of problem set. Hand-in: 29 November 2007. Download solutions here Additional Solutions Answer to Question 1 Answer to Question 10 Answer to Question 12 Answer to Question 13

Laboratory work is compulsory. You will be required to perform three experiments:

	1.	OCL class AB power amplifier
	2.	Negative feedback amplifier
	3.	The Wien bridge oscillator

Click here for details of the lab schedule.

There will be a mid-semester test for the purpose of assessment. I will inform you when it is going to happen. The main objective is to test the level of your understanding of the basic building blocks and how they work. It also serves as a health check of how well you've been progressing in this course.

The written examination will consist of a 2.5 hour paper, which contains a total of 6 questions, from which you have to choose 4 to answer. I will explain to you the format of the paper, and my expectations. Basically the paper aims to test what you have learnt from the course. As a matter of fact, I will never ask anything that you don't know or haven't seen, as the whole objective is to find out what you really know. The assignments are enough to stretch your mind, and I use exam only to assess your understanding of the essentials.

Altogether, the mid-semester test, lab reports and assignments will account for 40% of the final marks, and the written examination will account for 60% of the final marks.

I am usually available for consultation any time I don't have a class or meeting. But since our lectures are on every Thursday, it seems to be convenient if you can see me (if you have a question about your study) before the lectures. This will allow me to replicate interesting problems to the whole class, if it is appropriate to do so.

• Semi-log graph paper (73KB pdf file)
• Notes on two-port networks (180KB pdf file)

Learn with only your heart!

1. Paul R. Gray, Paul J. Hurst, Stephen H. Lewis and Robert G. Meyer, Analysis and Design of Analog Integrated Circuits, New York: Wiley, 2001.
2. Robert T. Howe and Charles G. Sodini, Microelectronics: An Integrated Approach, New Jersey: Prentice Hall, 1997.

• C. K. Tse, Linear Circuit Analysis, London: Addison-Wesley, 1998.