IEEE Circuits and Systems Magazine - Q1 2023 - 9

and the transistor was around for only 17 years and its
models were still being developed. In this work I learned a
great deal not only about transistors but also about techniques
for circuit analysis. After graduation, I was hired
by Cairo University as a full-time teaching assistant, and
I enrolled in a master's program to continue my transistor
modeling research. To be successful in this work, however,
I needed precision instrumentation as well as access
to a digital computer. Although Egypt at the time had two
IBM 1620 computers, gaining access to them for any length
of time was a challenge. So, after two years I decided that
much greater progress can be made by joining a graduate
program abroad. In the fall of 1966, through pure serendipity,
I ended up as a master's student at the University
of Toronto in Canada. Although I got to Canada and University
of Toronto by pure chance, it proved to be one of
the most important decisions I made in my life. I stayed at
University of Toronto for 37 years in a variety of roles and
enjoyed my time there tremendously.
Question 2: Although you started your research career
with transistor modeling, you branched out into other
areas. How did you select your research areas? Please
take us onto your research journey in circuits and the
work you did with your 65 graduate students.
Prof. Sedra: I arrived at University of Toronto reasonably
skilled in circuit analysis but needing to learn transistor
circuit design. I located a professor who had just returned
to Toronto from the University of Illinois where he was the
chief engineer of the Illiac IV computer design project. K.
C. Smith was teaching a graduate course on digital circuit
design. His approach to designing transistor circuits was
different than anything I had seen to that point and different
from anything that existed in the electronics textbooks
of that era. This is a very important point, and I would like
to come back to it later on. KC, as all students called him,
did not think of the transistor in terms of electrons and
holes but rather in terms of its current-voltage terminal
characteristics, and had very intuitive ways of using it in
designing multi-transistor circuits. I became hooked on
this approach and spent considerable amount of time and
energy to understand it and generalize it, in effect, creating
a methodology for the design of transistor circuits of
varying complexity.
Needless to say, I asked KC to supervise my master's
research. My project was to design circuit modules that
can be assembled in a system of computer-controlled
instrumentation. In the course of doing this, I became
interested in using current rather than voltage as the
controlling variable. This led me to inventing a versatile
three terminal block that I named Current Conveyor.
My PhD dealt with the application of current conveyors
FIRST QUARTER 2023
in synthesizing a wide variety of active circuits. Very
quickly it became clear that the current conveyor can
be a viable and, in many cases, a superior competitor
to the operational amplifier (op amp). I tried to interest
a Canadian semiconductor firm that existed at the time
(1968) to produce an integrated circuit (IC) current conveyor.
Unfortunately, at about the same time the IC op
amp made its debut (the Fairchild μA 709), and the op
amp won the budding race handily. Nevertheless, over
the years the current conveyor was used in many interesting
applications, in particular in biomedical circuits.
Hundreds of papers and a few books dealing with the
current conveyor were published by others.
After gaining my Ph.D., I joined University of Toronto
as an assistant professor of electrical engineering. Over
the subsequent two decades, I worked with KC Smith
and other colleagues to build an analog circuits group
that became one of the best in the world.
My early research with my graduate students was
in active filters. We moved from proposing active filter
designs using op amp (in the 1970's) to fully monolithic
filters including those utilizing switched capacitator (in
the 1980's and 1990's).
Most of the results produced by my graduate students
in this era were presented at the annual ISCAS conference
and published in the CAS transactions. Of noteworthy,
my very first conference presentation while I was still a
graduate student was at the very first ISCAS (called ISCT
at the time) that was held in Miami Beach, December 4-6,
1968. My paper dealt with the current conveyor.
Question 3: As a great educator in microelectronics, you
have mentored and guided the research of many graduate
students and coauthored widely used textbooks.
Throughout your career, how did you balance between
conducting research, mentoring students, and writing
textbooks? From your perspective, what characterizes
a successful educator?
Prof. Sedra: Since the beginning of my academic career,
I strove to become a fully functioning faculty member.
Let me tell you what this is: a " fully functioning faculty
member " is one who teaches both undergraduate and
graduate students, conducts research and supervises
graduate students, helps run the Department, and contributes
to the wellbeing of professional societies.
Over the years, however, I was able and permitted to
change the mix of my activities to better suit my interests
and talents at various stages of my career. In particular,
I pursued two avenues: textbook writing and academic
leadership and administration. Before we get into these,
however, I want to answer your question about balance.
First, I've always tried to make my research and teaching
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