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`GUEST EDITORIAL
`
`Peter Kinget
`
`A Born Educator and Researcher
`
`IIt has been a distinct pleasure to
`
`coordinate the special section fea-
`turing the contributions of Yannis
`Tsividis to (solid-state) circuits and
`systems education, MOS modeling,
`and analog and RF IC design.
`I came to know of Prof. Tsividis
`through his papers and books while
`starting out as a graduate student in
`Leuven. One summer we were fortunate
`to have a summer course on analog IC
`design on campus, and he was one of
`the instructors. I distinctly remember
`his crystal-clear lectures on continu-
`ous-time filters (with hands-on simula-
`tion exercises in the afternoon!). Most
`memorable was our discussion about
`my Ph.D. research topic, where, in a
`matter of minutes, he zoomed in on the
`key challenges and opportunities.
`A few years later after presenting
`some of my Ph.D. results at the CICC,
`I received a letter in the mail from
`Columbia University. It was a hand-
`written note from Yannis saying that
`he liked my paper!
`It was really thrilling and stimulating
`as a student, and later as a researcher
`
`Digital Object Identifier 10.1109/MSSC.2014.2347771
`Date of publication: 12 November 2014
`
`and academic, to have these types of
`interactions and encouragements. Of
`course, by now I have learned that this
`is really the hallmark of Yannis, and the
`articles in this issue illustrate this am-
`ply. He is a born educator and research-
`er. He is genuinely interested
`in the research of others,
`stimulates the development
`of new ideas, and always
`strives to find the original
`source of ideas. But, like
`no other, he is able to
`identify new directions,
`even if it means going
`against what is consid-
`ered common sense.
`His career sets an ex-
`ample for all of us in academia. It has
`been a distinct pleasure to have him as
`a colleague and mentor at Columbia.
`Being a guest editor is often con-
`sidered a “hard” or even “thankless”
`job. Not this time! All contributors
`were thrilled to write an article for
`this issue and were very punctual
`in delivering all materials in a short
`time frame, for which I would like to
`thank them.
`Dr. Colin McAndrew highlights Yan-
`nis’s contributions in MOS modeling.
`
`[Yannis] is genuinely
`interested in
`the research of
` others, stimulates
`the development
`of new ideas, and
`always strives to
`find the original
`source of ideas.
`
`Dr. Khoury and Dr. Banu, former Ph.D.
`students with a distinguished career in
`the IC industry, discuss the early devel-
`opment of integrated continuous-time
`filters. Prof. Krishnapura and Prof.
`Pavan, former Ph.D. students who
`followed in Yannis’s
`footsteps by choosing
`an academic career,
`recall their experiences
`as graduate students.
`Prof. Gabor Temes re-
`counts the impact of Yan-
`nis’s work in switched
`capacitor filters and other
`areas. Prof. Vallancourt
`has followed in his advi-
`sor’s educational footsteps
`and highlights Yannis’s unique contri-
`butions to circuits and systems edu-
`cation. Prof. Gray and Prof. Vandewal-
`le provide sidebars recounting their
`interactions with Yannis. Thanks also
`to the editorial board for approving
`the proposal to feature Yannis in this
`issue. Last but not least, I would like
`to thank Editor-in-Chief Mary Lanze-
`rotti for her skill and efforts putting
`together the issue.
`
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`Exploring and
`Explaining Circuits
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`Yannis Tsividis
`
`I
`
`Early School Years – How I Got “The Bug”
`grew up
`in a suburb
`near Athens, Greece, to a
`middle-class family that
`went through very difficult
`times. One of my earliest
`memories is of an attraction to musical
`instruments, especially pianos, and of
`my parents pulling me away from them;
`I was later told that they were afraid I
`would become a musician, and that I
`“would starve”. To this day, I regret not
`having learned to play an instrument
`well. Yet music is very much a part of my
`life. I credit it, in part, for my interest in
`radio and audio and, through those, in
`all things electronic.
`School was a refuge for me, and over-
`all I did very well in it, except in some
`subjects I truly disliked and had trouble
`with, like geography and history (and later
`chemistry). Those subjects were taught
`to us in a way that involved endless rote
`learning. I was born with limited memory,
`and found it very difficult to remember
`the huge amount of seemingly irrelevant
`information required to do well in those
`subjects. I would spend long evenings try-
`ing my best, ending up in crying episodes.
`In contrast to the above troubles, I
`loved other subjects in elementary school,
`especially math and later physics. This
`love extended to things that, at the time,
`I did not know had anything to do with
`math; I will mention one of them, which
`I think is interesting even today. In first
`
`Digital Object Identifier 10.1109/MSSC.2014.2348933
`Date of publication: 12 November 2014
`
`Photo by Barbara Alper.
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`grade, during class, I used to doodle a
`lot. My favorite doodle was a continu-
`ous line turning and crossing itself a
`number of times, and ending at the
`same point it had started; sometimes
`I would draw more than one closed
`curves crossing themselves and each
`other. I had noticed that if I filled in
`one of the resulting closed spaces on
`the periphery and left unfilled a closed
`space next to that, then filled in one
`next to the second one, etc., there was
`never an instance where, by the time I
`had finished, two adjacent areas would
`have to be filled in (Fig. 1). I must have
`tried this hundreds of times and it was
`always verified. I was so sure of this
`that I started telling my classmates
`and betting on it.1
`I used to ask a lot of questions
`in my favorite subjects and some-
`times I got in trouble for it. I vividly
`recall an incident in third grade.
`The teacher had just introduced r
`to us, saying that the diameter of a
`circle fits “three times and fourteen
`hundredths”
`into the perimeter.
`Now, in Greek, the word for “hun-
`dredths” is used both to mean just
`that, and also to mean “hundredths of
`a meter,” i.e. cm. I wanted to make
`sure I understand what the teacher
`had said, so I raised my hand and
`asked her, “Do you mean fourteen
`hundredths of the diameter, or four-
`teen hundredths of a meter?” She
`answered, “hundredths of a meter.”
`That really troubled me. I said, “But
`how is this possible? No matter if
`the circle is this tiny, or this big (I
`made signs with my hands), the
`periphery is always three times and
`fourteen hundredths of a meter?”
`She said “yes.” I was sure something
`was very wrong there, and tried to
`explain, but she cut me off with “Sit
`down, Tsividis! I said it’s fourteen
`hundredths of a meter!” I had to
`shut up, or I would probably have
`suffered a few slaps with her ruler.
`But the incident made an indelible
`
`1) About thirty years later, I decided to
`prove that childhood conjecture of mine; I
`was able to do it in a simple way, using dual
`graphs and a theorem I found in a graph
`theory book.
`
`If a project looks conceptually interesting,
`if it helps me get deeper into fundamentals,
`I am often drawn to it.
`
`impression on me, as it suggested
`rather strongly that authority fig-
`ures are not always right.
`From early on, I was interested in
`all things mechanical. I had been given
`a Meccano set (known in the US as an
`Erector Set), and I made all kinds of
`contraptions with it. I loved magnets.
`I was also fascinated with flashlights,
`and soon I was taking apart not only
`them, but also the batteries in them
`(I still remember the ammonia smell
`when I did this). There was a book
`in the house, something like “Intro-
`duction to Electricity,” for kids, and I
`really wanted to read it, but my father
`kept hiding it from me, as “it was not
`for my age.” I think he had mentioned
`something to the effect that, if kids
`get exposed to such things too early,
`they can become nerds; I guess this,
`in his mind, was as bad as “becoming
`a musician and starving.” I eventually
`read that book a few years later, and
`started experimenting with electro-
`magnets. But the book that played a
`decisive role in my life was one on the
`early years of Thomas Edison. I was
`totally fascinated by it. I kept read-
`ing it and re-reading it. I could relate
`to what was in that book! I could cer-
`tainly understand Edison’s fascination
`with experiments, as I was feeling it,
`too. Edison became my hero. Since
`Edison became a telegraph operator
`at a very young age, I decided to learn
`the Morse code, too. With a friend, we
`strung a pair of wires between our
`two houses and started sending each
`other messages. It was very exciting.
`For some reason, nobody complained
`that the wires went over a street
`crossed by cars.
`At one point I made, with my Mec-
`cano kit plus a couple of other parts,
`a high-voltage generator of my own
`design; I would turn a crank, which
`would cause periodic interruptions in a
`circuit involving a large electromagnet;
`
`the sudden current changes would
`cause voltages large enough to give
`you a shock. I later found out that such
`things already existed.
`One thing that intrigued me was
`that, when someone would ring our
`door bell, there would be interfer-
`ence on our AM radio, and it could be
`heard at all frequencies (talk about
`ultra wide band!) I started experi-
`menting using my own bell, attach-
`ing long wires to it and moving them
`closer to the radio, changing the
`bell’s repetition rate, etc. I had just
`gotten the radio bug. I later learned
`that sparks, like the one in my bell,
`had been in use in an earlier age in
`spark gap transmitters. Rather than
`disappointing me, finding out that
`my experiments and “inventions”
`were actually not new was encour-
`aging; it seemed that I was in good
`company, and had found my calling.
`I had no lab instruments, of course,
`so everything was done qualitatively.
`For example, I would test if the 4.5 V
`batteries I was using “had enough volt-
`age” using my tongue; it had to sting
`just enough, and then I would approx-
`imately know. This would later lead to
`a very unpleasant experience. An aunt
`of mine, coming from abroad, brought
`me as a gift a portable radio (with vac-
`uum tubes). I decided to make sure
`the battery in it had “enough voltage”
`using, as always, my tongue. I felt a
`horrible shock, not just in my tongue,
`but in my whole head, which violently
`
`FIGURE 1: Doodle example.
`
`
`
`
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`From Receiver
`Input Circuit
`
`From
`Demodulator
`
`Audio
`Stages
`
`Converter
`Tube
`
`Local Osc.
`Tank cct
`
`Bias
`
`Record Player
`Bias Bias
`
`FIGURE 2: Surgery used to convert our old AM radio to a transmitter.
`
`shot backwards. As it turned out, the
`battery in question was a 67.5 V one. I
`had no idea such batteries existed. For
`days after this, I had pain in my spine.
`I learned to be very careful with high
`voltage. A 400 V shock I experienced
`years later (fortunately, not on my
`tongue this time), while working on
`a power supply, completed my “train-
`ing” in this respect.
`At 12 years, I read in a children’s
`magazine an article describing how
`to make a batteryless radio using
`a galena crystal. I built one, and it
`worked. I was fascinated. I started
`experimenting with longer and longer
`antennas, trying to increase the signal
`strength. I started collaborating in this
`quest with a neighborhood friend. At
`one point we decided to erect a verti-
`cal antenna on his roof. It was a very
`tall wooden pole, several times our
`height, with a wire wound around it.
`As we were raising it, we felt (too late)
`that we could not handle the weight;
`the thing fell right onto the neighbor’s
`roof, causing serious damage. I still
`remember that neighbor, coming out
`in his underware, shouting that we
`were “shameless.” We decided to stick
`to horizontal antennas (for the time
`being); those could be 40 m long with
`no problem. The signals started to get
`stronger and stronger.
`
`Teenage Years
`Soon I was a teenager, and started
`going to parties where they played
`American popular music. I really
`liked that music! But I could not
`understand a word of the lyrics; at
`our school, English was not taught
`(except for a few basic words and
`phrases near the end of elementary
`
`school), and my family could not
`afford outside
`language
`lessons.
`So I tried to learn some English by
`myself, just in order to understand
`some of the words in those songs,
`or at least their titles. I gradually
`made some progress, and could
`finally understand what “Unchain
`my heart” meant, although I was still
`puzzled by “Itsy bitsy teenie weenie
`yellow polka dot bikini.” Anyway,
`this partial success was encourag-
`ing, so I kept up the effort. But what
`really gave a push to my self-train-
`ing in English was a small book by
`A. Marcus et al., “Radio for Beginners,”
`found and given to me by a friend. I
`opened it, and my mouth watered.
`Starting with a picture of a pebble
`falling into a lake and creating waves,
`the book went on to explain how my
`galena crystal radios worked, and
`gave schematics for several radios
`which used tubes for amplification.
`I really had to understand this book!
`I picked up a dictionary, and slowly
`worked my way through it. At the
`end of this effort, I had both under-
`stood, for the first time, how radios
`worked, and learned basic English.
`I have not had formal training in
`the language, before or since. Years
`later, I repeated this “self-training”
`with other languages and subjects.
`So now I could understand both
`radio electronics, and what those
`songs were saying. I was fascinated
`by rock music, and for a time I par-
`ticipated in the rehearsals of a teen-
`age rock group. I was trying to play
`the drums, the others in the band
`were trying to play other instruments,
`and none of us really knew what we
`were doing. We didn’t last very long.
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`But rock, as well as other popular
`genres at the time, became more and
`more important to us. Greek radio (at
`the time only four stations in Athens,
`all government–operated) had started
`playing some of this music, but not
`enough for us. And the formal way
`they used to announce the songs did
`not go well with the improvisation
`and downright craziness of rock. But
`there was, during the Cold War, an
`American radio station in Athens, and
`that was a different story. Announcers
`on it improvised, screamed, talked
`over songs, sang along with them, and
`somehow meshed with the music they
`were playing. They were having a ball!
`This fascinated us. We would listen to
`that station for hours each day.
`
`Radio Pirate
`I decided that improvisation had to
`come to Greek radio, and since the
`staid announcers on government
`stations were not doing it, I would
`try to do it myself. In the meantime,
`starting in 10th grade, I had enrolled
`in a correspondence course on radio
`repair, offered by a local school,
`which furthered my understanding
`of how radios worked. But my train-
`ing so far included only receivers.
`I started looking for a way to
`transmit. We had a beautiful Lafay-
`ette cathedral AM radio at home. It
`was a superheterodyne, with a self-
`oscillating mixer tube (or “converter”
`tube), and I now knew what that did.
`I connected a short antenna to its cir-
`cuit. Sure enough, the local oscillator
`signal could now be received at some
`distance, as I could verify using a sec-
`ond radio (the one with the 67.5 V bat-
`tery). This was extremely exciting; it
`was my first radio transmission (other
`than the more-than-ultra-wideband
`attempt using a bell, described above).
`I was now transmitting at a specific
`frequency, which I could control with
`the tuning knob. The problem was,
`this was only an unmodulated car-
`rier. How could I modulate it, and
`make it carry music? The same mixer
`tube that generated this signal had
`multiple grids (for the young read-
`ers: an electron tube “grid” roughly
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`corresponds to a MOSFET’s gate). One
`of those grids was connected to the
`radio’s input circuit, which carried the
`signal of the station being received,
`for mixing purposes. But I did not
`want to receive a station; I wanted to
`make my own station, so this grid was
`being wasted. I disconnected the grid,
`and decided to try using it for modu-
`lation, motivated by a vague notion
`I had that mixing, which is what this
`tube did, is some sort of modulation.
`I had access to the input of the audio
`stages of the radio and I could connect
`there the output of a record player.
`The output power tube provided an
`amplified version of the record play-
`er’s signal, so I thought of connect-
`ing that to the now-available grid of
`the mixer tube (Fig. 2). With the silent
`carrier being received on the second
`radio, I placed a record on the record
`player, and lowered the cartridge onto
`the record. The music came out of the
`second radio. I felt extremely excited
`and emotional. I was modulating and
`transmitting my own signal!
`I began a series of experiments,
`trying to increase the transmitter’s
`range by trying different pins on
`the converter tube for connecting
`the antenna, using a longer antenna,
`modifying the circuits, etc. Still, I
`could only transmit in my immedi-
`ate neighborhood. I made a radio
`frequency (RF) amplifier on a piece
`of plywood, and connected my sig-
`nal to it. This did something, but
`there was distortion. I started read-
`ing up on power amplifiers and
`how they are modulated, and kept
`building more and more circuits,
`until I finally could broadcast over
`several blocks. I could now have my
`own radio program. I bought a crys-
`tal mike, mixed its output with the
`record player’s signal using a resis-
`tive summer with potentiometers,
`and I was ready. I started broadcast-
`ing rock and soul music in the after-
`noons, after school. I announced
`music as I pleased, made jokes, and
`in general felt free to improvise.
`This caught on with the teenagers
`in my neighborhood pretty quickly. I
`was a high-school junior at the time.
`
`I kept up my efforts to increase the
`reach of my signal, now by “design-
`ing” transmitters from scratch. I
`reached a power of 10–20 W, which
`was enough to broadcast over sev-
`eral miles. My audience was now
`rather wide. At about the same time,
`I started hearing a couple of other
`kids, from other areas, doing similar
`things. It is not clear who was earli-
`est, but from all I can tell I was among
`the first radio pirates in Greece. The
`phenomenon
`started
`spreading.
`More and more pirate radio stations
`sprung up, and soon they were doz-
`ens, then hundreds, just in the Ath-
`ens area alone. Every neighborhood
`had its own radio pirate. Not once
`during this period did it occur to me
`that what we were doing may not
`have been legal. We freely broadcast,
`and even popular magazines would
`write about us. So we thought that
`what we were doing was fine; it was
`certainly tolerated by the authorities.
`School was becoming more de-
`manding. To the subjects I abhorred
`due to the rote learning they de-
`manded, namely geography and his-
`tory, another one was added: chemis-
`try, especially the “organic” kind. Now
`I really started struggling. Whereas
`I could do my math homework with
`ease, I would have to spend the rest of
`the evening trying to memorize dates
`in history, areas of countries in ge-
`ography, and formulas of substances
`with strange names in chemistry. As I
`was growing, my pains with such sub-
`jects kept growing, too. Fortunately,
`to compensate, I had my radio experi-
`ments at home, and at school I had
`math, physics and two new subjects
`that were a revelation to me: logic
`and philosophy. I took to those with
`an interest rivaling my interest in ra-
`dio. At one point, a few years later, I
`considered majoring in philosophy;
`I didn’t, but that discipline, together
`with electronics and music, fascinates
`me to this day.
`
`Studying Physics at the
`University of Athens
`I was now looking forward to uni-
`versity studies. Entrance exams in
`
`Greece were highly selective and
`very difficult at the time, requiring
`knowledge and skills that far sur-
`passed what was provided at most
`high schools, including mine. But
`there were separate, private tutoring
`schools that specialized in preparing
`students for the university entrance
`exams. They were a must (and,
`unfortunately, they still are). Like all
`students preparing for the exam, I
`enrolled in such a school, starting in
`the 11th grade, and indeed I found it
`essential. Unfortunately, during the
`last year of high school I had to quit
`preparatory school, as I could no
`longer afford it; worsening troubles
`at home demanded that I get a job
`instead, and I did, working in ampli-
`fier assembly at a local factory. I now
`had little time to prepare; I failed the
`entrance exam to the main engineer-
`ing school at the time, the National
`Technical University of Athens.
`Instead, I was admitted to the phys-
`ics department of the University of
`Athens. In retrospect, this turned out
`to be an advantage, as it broadened
`my perspective, and it would later
`complement my engineering educa-
`tion. The courses were extremely
`rigorous. First-year calculus was like
`a graduate course in real analysis.
`The real numbers were defined using
`“Dedekind cuts,” and we had to prove
`everything rigorously, including, for
`example, that 1>0. In the exams, if
`we would successfully calculate an
`integral without first proving that
`it existed, we would get no credit.
`Frankly, all this was way above my
`head and that of most of my class-
`mates; but it left something in me,
`which later matured and became a
`significant asset.
`The university was nothing like
`what I would later find in the US. The
`professors did not trust the students,
`and the students did not trust the
`professors. Courses were year-long,
`and were very difficult to pass; the
`passing rate in some of them was
`10 to 20 per cent. The climate was
`such that many of us would not go to
`most classes, preferring instead the
`local cafés. There was no homework.
`
`
`
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`At the end of the academic year, we
`would get together with classmates
`and pull all-nighters, cramming for
`the exams. We would pass some,
`fail others, and try again later in the
`year, or the year after that, until we
`passed, without having to re-enroll in
`the courses. That was the norm. For
`me, the situation was further compli-
`cated because I had to keep part-time
`jobs in order to make ends meet.
`Nevertheless, I did not abandon
`electronics and my love of broad-
`casting. Rather, I found a way to
`incorporate them into my univer-
`sity activities. The university was
`housed, at the time, in a number of
`disjoint buildings in downtown Ath-
`ens. To find out when and where
`an exam would be held, you had
`to look for an announcement out-
`side the office of the corresponding
`professor, in the appropriate build-
`ing, a few days before the probable
`date of the exam. If there was no
`announcement, too bad; you had to
`go look for one again the next day.
`This and other bureaucratic compli-
`cations were a nightmare, especially
`for students who lived far from the
`center of Athens. I decided to start
`an “Information Radio Station for 1st-
`year Physics Students of the Univer-
`sity of Athens.” Our class president,
`who lived close to the university,
`would take daily rounds and collect
`all information regarding exam dates;
`he would phone them to me; and I
`would announce them on the radio,
`
`using my transmitter. Students tuned
`in every day to hear the latest bureau-
`cratic details. This worked, and it was
`even reported in some newspapers.
`At the same time, I continued to
`broadcast my regular music programs.
`I needed to increase my range further,
`to reach a larger audience. I partnered
`with friends, who became regular
`announcers and the main source of
`funding, whereas I happily resigned to
`the role of engineer. You can see one
`of my transmitters, with 40 W output
`power, and with audio mixer inte-
`grated, in Fig. 3. The stations became
`very successful, attracting a lot of
`young listeners. We would give out our
`phone number, and would be flooded
`by phone calls by listeners; the gov-
`ernment phone company threatened
`to cut our phone off, because the large
`number of calls to the same number
`at the same time kept creating prob-
`lems with their equipment. The high-
`est power I reached was about 250 W,
`which was enough for us to be heard
`in a radius of about 25 miles, and we
`were told that at night our signal could
`be picked up in the island of Crete,
`over 200 miles away. High-quality
`amplitude modulation seemed to be
`my specialty. The modulation trans-
`formers I used were made by a local
`transformer shop to my detailed
`instructions, including the number
`of turns in each winding, and how
`the windings were to be split and
`interleaved for better high frequency
`response. Later, after years of AM
`
`broadcasting, I also got interested in
`trying FM, which was then being intro-
`duced in Greece. It may be surprising
`that I found it much easier than AM! I
`ended up using a single power tube in
`oscillating mode, and applied ampli-
`tude modulation to it. Since this was
`not a very stable oscillator, the result-
`ing voltage variations on the tube’s
`plate (corresponding to a MOSFET’s
`drain) affected the oscillator frequency
`and resulted in frequency modula-
`tion, which for some reason was of
`exceptionally high quality. The circuit
`became popular with a number of FM
`radio pirates, who started becoming as
`numerous as AM pirates. This situation
`eventually led to FM private radio sta-
`tions in Greece.
`In the meantime, I had obtained
`my radio amateur license and had
`begun to make regular contacts on
`shortwave with other amateurs all
`over the world. Starting in the 2nd
`year of my university studies, I also
`got my first taste of “publishing.”
`There was a magazine in Greece at the
`time, called “Electronic News,” and
`they accepted to publish a variety of
`articles by me, mostly on construc-
`tion of hobby circuits (amplifiers,
`receivers, transmitters, alarms, metal
`detectors, etc.), some resulting from
`modifications of circuits I would find
`in foreign magazines, and some of
`my own design. I wanted to include
`transistor circuits but, in contrast
`to vacuum tubes, which I knew a lot
`about, transistors were still a mystery
`
`(a)
`
`(b)
`
`FIGURE 3: (a) A 40 W transmitter I made while in college in Greece, with incorporated audio mixer. (b) View under the chassis.
`
`18
`
`FALL 2 0 14
`
`IEEE SOLID-STATE CIRCUITS MAGAZINE
`
`IPR2023-00817
`Theta EX2002
`
`

`

`THETA2021078
`
`to me, and I did not know what I was
`doing. One fun example of the sort
`of thing I came up with was a circuit
`for a “radio for the shipwrecked,”
`using two batteries in series consist-
`ing of plastic thimbles in which cop-
`per and zinc electrodes were placed,
`and were filled with sea water — the
`one thing that these hypothetical
`users would never run out of. The
`circuit included two bipolar transis-
`tors; the only element connected to
`the base of one of them was a capaci-
`tor. These days, if a sophomore com-
`mits such a blunder, I consider it a
`mortal sin; but back then I did not
`know any better. Neither did the edi-
`tors of the magazine, I guess, as they
`let me publish it. The funny thing is
`that those circuits worked! Decades
`later, as I leafed through some of the
`magazine issues I had kept, I was
`embarrassed to see those designs,
`and started wondering how on earth
`those circuits worked, if there was
`no path for DC base current to flow.
`Knowing by then how transistors
`worked, I solved the mystery: The
`collector-base reverse-bias leakage
`current, of which there was plenty in
`those germanium transistors, served
`as the base DC bias current.
`It is clear from the above, and it
`became clear to me from other indi-
`cations, that I needed better train-
`ing. With money I had saved from
`repairing radios, I enrolled in a corre-
`spondence course called “Electronic
`Engineering Technology” from CREI
`(Capitol Radio Engineering Institute)
`in Washington, D.C. This course,
`which was at a rather high level, with
`lessons written by experienced engi-
`neers, really increased my under-
`standing of electronics well beyond
`the hobby level. I could now publish
`more competent articles in Electronic
`News, including on theory, e.g. on
`resonant circuits, modulation, etc.,
`as well as a series of articles I called
`“The Mathematics of Electronics.”
`
`Volunteering in the Electronics Lab
`The physics department of the univer-
`sity had a sort of Master’s program in
`electronics. The labs there attracted
`
`me like a magnet. I presented myself
`to the professors, and offered to help
`with anything I could. I was soon
`repairing instruments for the lab and
`helped build things, and they liked
`me. They asked me – to my surprise –
`to act as a teaching assistant for some
`of the lab classes for the Masters’ stu-
`dents. I was thrilled, although I was
`not sure how this would go, as I was
`only an undergraduate. But it went
`well. There is one experience from
`those times, which I will never forget.
`One of the lab exercises was to build a
`power supply using a kit from Heath-
`kit. One of the teams called me, com-
`plaining they had powered the unit
`up and were not getting a voltage out.
`I leaned over their chassis to inves-
`tigate, and I spotted an electrolytic
`capacitor actually bulging, with the
`plastic around it melting and strip-
`ping off the metal. I screamed, “Pull
`the plug, quickly!” But before they
`could do this, the capacitor exploded,
`literally in my face. At the time I had
`a beard, and it was covered by a white
`substance from the capacitor; I looked
`like Santa Claus. Worse, one of the
`capacitor’s terminals was blown over
`and got stuck, like a needle, into one
`of my eyebrows. I do not know where
`I got the calm, but I found this a per-
`fect “teaching moment”; rather than
`cleaning myself up, I made the rounds
`in the lab and showed everybody
`there what can happen if they do not
`obey proper polarity with electrolytic
`capacitors, especially with a few hun-
`dred volts across them. I am sure they
`never forgot this.
`But I also got to do research in the
`electronics lab. I had read in Popular
`Electronics (an American magazine,
`which back then you could find in
`some of the kiosks of Athens), that
`it is possible to convert a flame into
`a loudspeaker by applying a time-
`varying voltage across it. Not many
`details were given. Together with my
`classmates, Demetri Paraskevopoulos
`and George Keramidas, we decided to
`look into this. Working in Demetri’s
`home, we connected a radio’s audio
`signal (through a transformer) in
`series with a DC voltage, and applied
`
`the sum to two electrodes, one near
`the bottom and the other near the
`top of a flame, which was produced
`by a Bunsen burner fed from a butane
`gas tank. We turn the thing on, and
`we are suddenly listening to a highly
`distorted version of the evening
`news, coming out of the flame! We got
`really excited, and started a series of
`experiments, literally groping in the
`dark (nothing wrong with that). We
`tried various magnitudes for the DC
`and AC voltages; we varied the dis-
`tance between the electrodes; and we
`tried introducing various substances
`into the flame (salt seemed to work
`particularly well). Finally, we tried
`lowering the flame temperature, by
`reducing the flow of gas, turning its
`color from blue to yellow. We found
`that lower temperatures resulted in
`less distortion; unfortunately, they
`also resulted in smoke which dark-
`ened the white walls, to the dismay
`of Demetris’s mother. So we asked
`the Electronics Lab at the university
`to house the experiment, and they
`gave us a room and equipment for
`this purpose. You can see that setup
`in Fig. 4. We continued the experi-
`ments there, and developed a theory
`to explain our observations. We wrote
`a one-page report on it, in English,
`which we later used as part of our
`applications to US universities. All
`three of us ended up in the US.
`
`Organic Chemistry
`Catches Up With Me
`I mentioned earlier