My Creative Evolution

Stepping in the world of machinery

1954.  I came into the world...

1959.  At the age of five, I made my first “invention” -- a hydraulic integrator (water clock). In the presence of my family I filled a tin-can with water, made a small hole in it and starry-eyed watched the water slowly draining from the tin. Perhaps that was my first encounter with the pressurelike and flowlike attributes of the world, deeply impressed me. Thus I was sure that one day I will become a technician.

Coming to know of electricity

1964. As a ten year old boy in a primary school I was captivated by the magic of electricity. The first electrical device that really intrigued me was a DC bell given to me by an electrician acquaintance. It was a real mystery to me how the bell vibrated on its own, but I managed to figure it out...
I remember “inventing” something like an inertia sensor or what at present, in  security systems, is referred to as tilt sensor. I fixed the screw cap of a small electric bulb to an elastic terminal of a 4.5V flashlight battery so that the other bulb lead should touch lightly the stiff battery terminal. Then I enclosed this “device” in a box and launched it in a basin full of water. The “ship” slowly swung and the bulb rhythmically flickered, imagine, by itself! My family was enraptured with my spirit of invention. Then I was absolutely certain I would make an "excellent" electrician!

1967. At that time I enjoyed making electromechanical devices. My favorite elements were polarized relays - both neutral and with memory - solenoids, electromotors, potentiometers etc. When building a simple “servo system” by two potentiometers, polarized relay and gear motor, for the first time I was faced with the great idea of the negative feedback principle presented in its primitive electromechanical form.

My simple servo system: The P2 potentiometer's slider (driven by the motor M) followed the movement of P1 slider (driven by me).

In capture of electronics

1968. As an eight grader I was fascinated by the mystery of electronics and that passion has not left me since. My first electronic device was a multivibrator, which controlled a lamp with a flashing light. There was a "presentation" at home again - I turned off the light in the room and my parents watched as the light flashed again by itself. 
My favorite circuit was a regenerative supersensitive acoustic relay; it was also my first encounter with the phenomenon of positive feedback in electronics. Again, there was a "presentation" at home where I clapped and whistled in the microphone to make the bulb flash in front of my family's admiring gaze.

My acoustic relay

I also made a small HF generator in a matchbox, which I used to jam the VEFs (Russian portable radios) of the older ones who proudly were walkintg down the main city street and tried to impress the girls :-) My professional choice was definitely set - I had thrown in my lot with electronics!

1969. But I was truly captivated by the magic of electronics when I enrolled in a high school (Lomonosov College of Electrical Engineering, specialty Automation) with enthusiasm. I liked all kinds of automatic and cybernetic devices behaving like living beings - light-, temperature-, motion-activated electronic circuits, etc. In junior classes, in the automation club at the technical school, I managed to build a light-sensitive cyber car following a white path on the floor.

Invitation to Automation Evening, of which I was the main organizer

At that time, I got valuable ideas from an amazing book with very interesting electronic circuits and illustrations - Fun Electronics by the Polish popularizer of electronics Janusz Wojciechowski.

Fun Electronics by Janusz Wojciechowski

1971. Inspired by it, later on, in the senior classes, with a friend and school-mate we spent a year building a robot ("he" :-) In his "heart" I embedded "color music device" (for which I sacrificed my slide projector), and in his body I hid an entire tape recorder (I sacrificed my beloved "Sharp"). So the robot could speak, and his heart would be colored in time with the speech.
In the spring of 1971, he successfully presented himself at the city and district exhibitions, and in September of the same year, at the Fourth National Exhibition in Plovdiv...

Photo with the robot, at the 4th exhibition of youth technical creativity in Plovdiv (I am on the left of the photo)

... where he attracted the attention of government delegations.

The robot welcomes the delegation of the Central Committee of the Communist Party, headed by Todor Zhivkov (I am on the left of the photo, controlling the robot with remote radio control)

We were awarded gold medals that gave us an advantage in applying to the university. So, even then I knew that I would enter the Technical University of Sofia but I did not know that my whole life would be connected with it.

The gold badge from the 4th exhibition in Plovdiv (1971)

It was around that time I began feeling disappointment because I did not like the formal way I was taught physics, electricity and electronics. 

1973. In the last year at the technical school, I became passionate about the invention. I had the fortune to read a paper on invention in the Patent Office column of Young Designer, an amateur magazine. As a result, I was seized with inventive fervor; many ideas dawned on me. Finally, I entered a competition developing a clever electronic device - a presence detector, sensing a human in the premise and automatically turning on/off the lighting, power, etc. It consisted of two object detectors, logic stage and 74193 reversible counter controlling the load. It counted the number of people in the room and turned on the lights if it was non-zero. Receiving a junior inventor's certificate (a "little patent") I already wanted to become a real inventor.

My first "little patent" for an invention

I graduated from high school with a gold medal for excellence.

My gold medal for excellence

In the army

1973-74. After school, I joined the army. It chanced to do my military service at a Department of Electronics of the Military High School in Veliko Tarnovo. There I participated in equipping of classrooms and laboratories in the school's new buildings with electronic systems.

Soldier in the Electronics Department of the Military School

My military service passed under the sign of inventiveness. In the course of the whole 1974 I was sending proposals to the patent office. In October, I managed to obtain first real inventor's certificate (a similar to patent document).

One of my ten credentials

At that time, I already had interested in all sorts of creative thinking techniques - the lateral thinking of de Bono, Osborn's brainstorming, Gordon's synectics etc., and I began form own such techniques. In time of my army service I obtained further three inventor's certificates in a variety of fields. I was also awarded by the Minister of Defense with a diploma.

My certificate from the Minister of War

At the height of inventing - student at the Technical University

1975. At the end of 1975, I entered the Technical University of Sofia where I was even more disappointed by formal education. I was learning my lessons diligently and passing all my examinations; and yet I had the feeling I did not understand the essence of things which I in fact needed. Finally, I refused to have anything  to do with mathematics and began to rely only on my imagination. Nevertheless, my spirit of invention was there; I had all sorts of ideas, some of them almost impossible. Here are some of them.
  • I tried using electrolysis for data recording. Such an element like a famous memistor, I thought, might replace the conventional magnetic tape; it would be a perfect recorder.
  • Once, looking at the upper side of a door opening and closing, I was struck by an interesting geometrical phenomenon: when two almost parallel lines move slightly against each other then their crossing point moves significantly in a perpendicular direction. I used that idea to "invent" some scanning devices. Later on I would observe that phenomenon when the potential diagram of a differentially supplied linear resistor crosses the zero potential line in a point referred to as "virtual ground", in the superimposed V-I curves etc. Then I learned that it was a well known optical effect.
  • For a long time I was obsessed with the phenomenon of shock-excited oscillations in mechanical, electrical etc. systems. I noticed the number of free oscillations was logarithmically dependent on the input shock magnitude. Thus I obtained a variety of natural analog-to-digital converters, "ringing" LC identifiers, measuring transducers using multiple reflections etc.
Finally, I received two more patents for torque converters.

One of my patents

I became involved in the research work of the Vibration and Noise Research Laboratory at the Department of Mechanics.

My workplace in the laboratory of "Vibrations and Noise"

I developed electronic vibration measuring devices during my studies and in the first years after my graduation.

The vibration measurement system developed by me

My development "Vibration measurement system" was awarded with a second Golden Badge at the X National exhibition of youth technical creativity in Plovdiv, 1979.

My second gold badge

I took part in tests of buses, tractors and trucks.

During tests of a bus at the testing ground in NIPKIDA, Druzhba district, Sofia

I participated with reports at scientific conferences of students and young researchers in Sofia and Varna.

My National Student Science Conference Award, 1980.

When I was in the upper courses, I led an electronics club to the first-year students, trying to explain transistor circuits to them.

I finished my studies with a diploma thesis on Vibration Measuring System.

My thesis assignment

First rudiments of circuit principles

1977. Sometime around this time, I began to notice interesting circuit phenomena. Here are some of them:
  • In the measuring laboratory, where I was working out electronic measuring devices, once, examining a circuit diagram of an ultralow-frequency amplifier stage, I encountered a "strange thing put into the feedback loop" - a blocking capacitor. I drove that amplifier stage with a sine wave decreasing the frequency and looking on the scope before and after the capacitor. To my great surprise, the amplitude after stayed invariable as long as the amplitude before increased to saturation!
  • Another "strange thing" I observed was the short-circuit protecting resistor connected in series with the op-amp output and put again into the negative feedback loop. A many years later, I would grasp that phenomenon. Quite later on I would use that powerful idea to lay down the principle of deliberate disturbance in negative feedback systems and to convert a negative feedback follower into an amplifier (i.e. to build a negative feedback amplifier logically).
  • Also, I remember, I built an op-amp voltmeter connecting an ammeter movement into the negative feedback. Then I added a variable resistor in series with the movement and tried without success to arrange things so that 1 V applied to the voltmeter causes a full-scale deflection of the movement. To my surprise, when I increased the series resistance, imagine, the needle did not move; at the same time, the op-amp output voltage increased! What a magic - as though the op-amp destroyed the resistance! Much later I would manage to realize that phenomenon and to generalize it in the principle of removing a voltage by an antivoltage.

With amateur enthusiasm and inventiveness - employee at the Technical University

1981. After my graduation from the Technical University of Sofia I had the opportunity to choose where to start work. After a short hesitation, I chose to remain faithful to the institute where I had studied... and I was not wrong, because it was my calling... and I began working at the Analog Electronics Laboratory of the Department of Computer Systems as an engineer.
I continued with inventing but I had already decided to generate only realizable ideas. My "technology" included three stages: first, I generated an idea; second, I experimented with a device based on this idea; third, I published a paper in an amateur magazine.

1982. Once, I accidentally connected a red light-emitting diode across a green one and observed an interesting phenomenon -- the red LED extinguished the green one. As I had already tried to make a three-position zero LED indicator so I immediately used that new effect. Thus I invented an extremely simple and nifty circuit consisting only of three resistors (RB, R1, R2), two transistors and, of course, the three LEDs (one green and two red). RB might be omitted; R1+R2 determined a LED current; a voltage divider R1/R2 set a voltage threshold - see my Codidact paper 3-LED voltage indicator (an inventor's story). Encouraged by obtaining a patent, I immediately began improving that circuit. After the "point" version I was smart enough to "lift" the forward LED voltage by additional diodes connected in series. Thus I consecutively invented a "linear" version of the zero LED indicator and a "плане" one (for the latter I obtained another patent). Then I devoted a series of papers to those circuits publishing them in the Young Constructor and Radio and TV amateur magazines.

One of my patents for LED indicators

1984. Something similar occurred when I tried using a current reed relay as an AC current consumption detector. To increase the relay sensitivity I placed a small magnet near the glass capsule and began slowly varying its location. At one moment, the vibrating reed switch got stuck in the closed position. Of course, I was initially disappointed by that harmful effect but I soon realized that the element obtained a wonderful feature -- a kind of memory. When I aimed one pole of an external magnet at the one side of the capsule the reed switch stuck in the closed position and remained in that state even after I had removed the magnet. And vice versa, when I aimed the same pole at the other capsule side the reed switch opened and remained in that state even when I removed the magnet again.

Magic Switch.What a wonderful element that was! It consisted of only a reed switch and a magnet. Nevertheless, the Magic Switch simultaneously incorporated sensitive bipolar magnetic sensing, nonvolatile memorizing, due to its hysteresis, and switching! So I immediately applied it to "magically" arm/disarm the burglar alarm in the car I had just bought. 

Magic Sensor. Nevertheless, I managed to increase the reed relay sensitivity by an additional AC magnetization. Then a new idea suddenly aroused - to affect an internally AC pre-magnetized reed switch by another external DC magnetic field. It turned out to be a wonderful element now consisting only of a reed relay and an adjustable resistor! But it had all the functions of a supersensitive bipolar magnetic sensing and pulse-width modulation.

Magic Control. I used to carry out the experiment of a magnetically controlled DC motor which deeply impressed my colleagues. For the purpose, I connected a small DC motor via the reed switch of the relay to a step-down transformer. Then I supplied the relay coil via the variable resistor from the transformer and adjusted the resistance so that the switch began tapping slightly. After that I hid the "device" in a big box and became a "magician". I aimed the one pole of an external magnet (my "magic wand") at a distance of about 30 cm from the box - the motor started to turn slowly. After that I began moving the magnet slowly - the motor changed speed. Then I aimed the other pole of the magnet - the motor reversed the direction of the revolution.

Magic Compass. It turned out that the magnetic sensor is so sensitive that it picks up the Earth's magnetic field. I made this little discovery quite by accident on my workbench - as I moved the circuit board with the device, I noticed that its sensitivity changed. I pretty much figured out what the reason was, and at one point I realized it was the earth field. To make sure of this, I powered the device with batteries and went out into an empty space in front of the house. Thus I made an electronic compass.

During this period, I published a total of about 50 popular science articles. A series of articles was devoted to LED indicators invented by me, another - to the magnetically controlled sensors "Magic Switch", and a third - The Secret of Invention, the technology of the invention. I received two more patents for inventions (LED null indicators).

1985. I started teaching as a part-time assistant in the disciplines Digital Circuits, Analog Computers, Laboratory Practice. I tried to explain circuits in the simplest and most understandable way for the students and so I gradually started to develop my own circuit philosophy. I participated in the development of laboratory setups in these disciplines.

1986. I passed a competition and was appointed as a research associate in the research laboratory at the department. I participated in two research projects, some of them about electronic devices for controlling internal combustion engines. I developed a thyristor system for control of vibrating setups and a computer system for recording mechanical oscillations, which were used in the educational process of the Department of Mechanics.

I put a lot of effort into updating the Analog Circuitry Lab (1316) by developing new laboratory set-ups connected to networked PCs. I conducted the first labs with them and experimented with some organizational ideas. I presented the results with two reports at the Scientific Conference "Radio Day - 86". This is how the MICROLAB idea was born...

Educational technology MICROLAB

Teacher at the Technical University

1987. I began working as an assistant professor at the Department of Computer Science and began teaching Analog Electronics to my students. I continued trying to reveal the secret of circuits. The paradox was that I was accurately teaching them to pure students but...actually I didn't still understand them:)

Right from the beginning, I undertook with enthusiasm to improve the equipment of the Analog Circuit Laboratory where I had to teach. Because of lack of lab instruments I made a decision to convert a popular PC (like Apple II) into a "measuring laboratory". In order to generate and measure voltages (from -10V to +10 V), I provided every PC with digital-to-analog and analog-to-digital periphery. It consisted of four 12-bit DACs (DAC 1200 of a National Semiconductor) and a 4-channel ADC using the third DAC as a building block. I enclosed that periphery in a flat box thus obtaining turning out a very successful technical solution - MICROLAB system. It was a programmable voltage source, a functional generator, an oscilloscope (at low frequency only) and even a power supply for an analog circuit under test! I did the first labs with them and experimented with some organizational ideas. I presented the results with two reports at the Scientific Session "Radio Day - 86". Thus began the idea of MICROLAB...

Using computers in laboratory

During the winter semester of 1987/88 academic year, I experimented with a new method of conducting laboratory exercises, called MICROLAB Educational Technology, in which students worked individually with a flexible schedule. Each student had an individual diskette on which to record the results of laboratory experiments.

Individual timetable MIKROLAB

The laboratory setups grew into MICROLAB system, which was adopted for production by the Training and Production University Division. A total of 20 units were produced. such systems.

MICROLAB system in lab 1316

I gradually realized that MicroLab was a powerful idea. In contrast to the traditional lab oscilloscope showing data only as a two-dimensional diagram, MicroLab was able to represent results in an unusual way using the educator's imagination. So I developed a set of clever laboratory experiments visualizing circuit phenomena investigated by "living" (interactive) pictures on the screen.

My favorite experiment was an interactive voltage diagram of a linear resistive film with resistance R supplied from its two sides by voltage sources V1 and V2. MicroLab continuously measured the voltages (V1, V2 and probe voltage VP=VOUT) and drew a voltage diagram on the screen. Varying V1, V2, r1/r2 (moving the probe) I and my students respectively  "invented" a set of useful devices: voltage dividers, summer, subtractor, motion-to-voltage converter, multiplier etc. When V1=-V2 a virtual ground appeared on the film and then we made a "manual inverting amplifier": one student was changing V1 while the other student was looking at the virtual ground (a zero indicator was attached) and changing -V2 so that VOUT=0. In the meantime, the voltage diagram turned around the virtual ground. Much later, I described this experiment in a Wikibooks story. I developed various computerized laboratory experiments, which were used to illustrate unknown properties of the studied electronic circuits. I still use some of them.

1988. I worked out an educational technology based on that approach and set up a student problem-solving research team. We held regular meetings, the results of which we showed on a board in front of the laboratory. Each laboratory exercise was attended by a representative of the group who "assisted the assistant." Some of the participants in the problem group are now lecturers in the department.

I believed that approach might be applied in all the areas of the Electrical Engineering education. Later on, I began popularizing the computer-based approach in an educational laboratory publishing a series of papers dedicated to the MicroLab. A movie about MicroLab was made and shown on TV.

1989. I participated successfully in two conferences in the country and in the international exhibition for polytechnics - Prague, where I presented the new setups MICROLAB, and in the international seminar Implementation of Information Technology in the Learning Process in Leningrad (Saint Petersburg now) with two reports. I participated in the Second and Third National Conference SAITNI in Albena.

I started a PhD at the Department of Pedagogy on the topic of Computer-Based Educational Technology for conducting educational laboratory experiments. I was inspired by the prospects in this field of education.

My first Ph.D

Only, the educators did not appreciate that approach. They thought it was more difficult than the traditional approach. So MicroLab didn't gain wide popularity; I didn't win the public recognition I needed...

I wrote a Student Manual for laboratory exercises in the discipline Analog Circuitry based on the educational technology MICROLAB. It was published by Tehnika Publishing House.

My Student Manual on Analog Circuitry

A temporary digression to business

In the end of 1989 a "wind of change" blew and I decided to set up a business. At the next 1990, I set up the DidaLab firm (Didactic in Laboratory) and began designing instructional equipment for engineering and vocational education. First, I constructed the DidaLab System -- more functional, plug-in board version of MicroLab intended for IBM PC AT. In order to investigate all kinds of electronic elements I designed an additional module consisting of voltage-to-current and current-to-voltage converters.
Then I developed a flexible medium comprising a variety of building blocks: meters, power supplies, loads, element holders, objects prepared to be investigated, etc. All of them were equipped with magnetic fixing and snap (spring) terminals. Some building blocks looked quite strange -- e.g., conductive foam "resistors" which might be cut, stuck and pricked by needle probes.
In addition, I worked out a set of old-fashioned but clear fixed-range analog meters -- both unipolar and bipolar -- so that the students might obtain simultaneously data in a digital, graphical and "mechanical" form.
In the meantime, I improved the Magic switch, managing to obtain a patent and a trade mark. Based on the Magic switch, I designed a car immobilizer and then set up another firm Magi in the field of security systems. So I bettered my circumstance, but I soon realized business was not my vocation.

1990-1996. During this period, I was engaged in implementing what has been achieved in practice. I first applied the MICROLAB technology in the technical school in Kozloduy, and under my guidance a team of students developed additional modules and stands for testing step and DC electric motors. I also trained teachers in these disciplines.

At the College of Communication Technology, I conducted a 3-year course with students, which I called Electronics for Inventors. The idea of ​​the course was to present the circuitry to them in an unconventional and entertaining way so that they would love it. The director provided us with a room where we furnished a laboratory and held our meetings. We regularly reflected the results on a board in the lobby of the college. I also shared my experience with the teachers of Semiconductor Elements and Measuring Technology.

Electronics for Inventors course

I developed a new DIDALAB system, constructively implemented as a controller for a 16-bit computer. I made sets of specially adapted devices and objects for the purposes of educational laboratory experiments (with spring terminals and magnetic fastening). I wrote a manual for working with the system and a set of interesting experiments, which was printed in a limited edition.

DIDALAB objects

I developed original computerized experiments in which invisible electrical quantities were visualized on the monitor screen - living analogies, living voltage diagrams (video), living IV curves, etc.

"Live" voltage diagram on the monitor screen

I made my first attempt to promote the technology by publishing a series of three articles (BG) in the new Open Education magazine in the form of an open letter.

Realizing a vocation finally

At the age of 40, I finally began to reveal my vocation - to grasp the ideas behind circuits, then to generalize the ideas into fundamental principles and finally to expound more and more circuits to the students by means of the extracted principles.

Building a philosophy of electronic circuits

1997. I realized that my vocation is not so much in organizing the learning process but rather in revealing and explaining the secrets of electronic circuits. I had gained enough experience, which allowed me to build an original, based on human intuition heuristic course in the field of circuitry. In this way of teaching, electronic devices were not given ready-made in their complete and perfect form, but were built sequentially with the help of a hierarchical system of more elementary building blocks, connected in accordance with a system of basic circuit principles. I promoted this approach by presenting seven papers at three conferences and publishing a series of 14 articles in Engineering Review magazine under the general title Looking for the Idea.

1998. I began preparing a series of three large articles concerning some of my powerful ideas for IEEE on Education.

1999. I began preparing a new series of papers How to Invent Electronic Circuits which I intended proposing to some amateur magazines.

2000. I decided to publish a book titled Electronics for Inventors but I was disappointed by the limited potentialities of typography to present color and movement... the Internet was entering in life...

Promoting my philosophy on the web

2001. I started to realize my ideas on the web in the form of a website circuit-fantasia.com entitled How to understand, present and invent electronic circuits. To attract the attention of visitors, I made it animated and interactive through Macromedia's Flash product. Unfortunately, this year, Adobe stopped supporting Flash Player. But if you want to see it, you can solve the problem by installing the Ruffle extension on your browser. Its popularity is high - over 238245 visitors since its opening until now.

Circuit Fantasia home page

I started uploading my classes with my students on the site. In 2004, I periodically uploaded the resources related to the conducting of the seminars, including in English, of the discipline Specialized Computer Electronics (SCE) of the Faculty of Computer Systems. In 2005, I uploaded the lectures and laboratory exercises. I even kept a record of the students' attendance and participation on the site (groups 6163 and 64). I also maintained feedback with students through electronic forms embedded in web pages. At the same time, I uploaded the materials on the discipline Pulse and Digital Circuits of The Faculty of Communication. The idea of ​​this course was not to give circuits in advance but to build them at the moment. For this purpose, we gradually built a collection of circuit blocks, which we used to build even more complex circuits. I also attracted famous specialists and teachers from abroad to take part and express an opinion.

This endeavor proved to be fruitful, and in fact it was the beginning of an e-learning (then cloud services and the Moodle platform were not widespread), which is very relevant at the moment. I decided to promote it among my colleagues by presenting a total of 7 papers at four conferences in the country and three abroad. The most authoritative was EWME’2006 in Stockholm, where I expounded the philosophy of this heuristic way of teaching.

At the poster

I shared what I had done with my colleagues from the Department of Computer Systems, sending them an enthusiastic email on May 23, 2004, on the eve of the celebration of Slavic writing. Unfortunately, I did not get the encouragement I needed and I moved on on my own... and so on until today...

Wikipedia

2006. In order to make my achievements available to a wide audience outside the country, I started contributing to Wikipedia. For several years, I made a total of 7700 edits of texts on web pages related to circuitry, derived mainly from my classes with students. I created a new Wikipedia page on Miller theorem.

Wikbooks

2007. Wikipedia did not allow me to develop my ideas well because it was made up of separate, loosely linked web pages. So, a year later, I moved to Wikibooks, where I created the e-book Circuit Idea, dedicated to uncovering the basic ideas of electronic circuits (conceived as a "philosophy" of circuitry).

2008-2011. In the spring of the 2007/2008 academic year, I carried out my largest web experiment, involving students from 10 laboratory subgroups of Compter Systems specialty in the discipline Specialized Computer Electronics in the coverage of the classes in Circuit Idea. The wiki idea allowed individual students to work on the overall project by uploading various class materials - texts (in English), photos, diagrams and more. We even managed to create a large page together dedicated to Ohm's experiment, used unconventionally for the purposes of modern circuits with operational amplifiers. Pavlin, Virginia students took an active part, creating profile pages in Wikibooks. In total, I developed in detail 25 modules (web pages). I helped them create 10 web pages for their lab groups.

Later, in 2010, the students from group 57 created a web page in which they showed the "pseudo-invention" and the study of an interesting electronic circuit of an LED indicator according to my author's certificate of invention from 1984.

During this period, I presented four more reports, mostly at foreign conferences.

2011-2013. I started a free doctoral program, which gave me the opportunity to collect and hierarchically organize my ideas in circuitry. My dissertation on "A system of heuristics for a functional processing of basic electronic circuits" was devoted to the use of the heuristic approach to reveal the basic ideas in circuitry. A key publication to it was devoted to the use of Miller theorem to modify the characteristics of electronic circuits.

The diploma of my Ph.D

2012. I joined the scientific social network ResearchGate and continued to develop my activities there, started in Wikipedia and Wikibooks. Live contacts with scientists and specialists from all over the world in the network's forum proved to be very stimulating for the birth of new ideas. I started to cover my work with students in the scientific network as most of the discussed problems were extracted and dedicated to my work with the students in the circuit engineering specialties that I teach. Some of the questions I asked were also attended by students who specially created an account on the network. We even did this "live" from the lab during the exercises.

So far, I have asked a total of 132 questions (topics for discussion) dedicated to interesting circuit phenomena and I have answered (taken a stand) with 3547 comments. I have published a total of 43 articles. This made me a popular author on the web - so far I have a total of 1001348 visits and 2036 recommendations. My rating is 21,22  points; the scientific interest is 120.7.

More than 178 times I have been awarded by ResearchGate as the most visited representative of the department, university, department and the state. Unlike the generally accepted passive way (uploading posts for rating purposes), I use the ResearchGate network actively, by participating in the forum.

StackExchange

2014. I joined (and is collaborating so far) in the largest question and answer platform StackExchange (Electrical Engineering section), where questions are constantly asked and answered in the field of circuitry. This gave me the opportunity to share with a wide international audience the problems I solve with the students in the lecture hall and the laboratory. So far I have asked a total of 12 questions dedicated to interesting circuit phenomena and I have written 458 answers. I have a total of 2943 (+1582) edits and 981 reactions from other participants. What I created was read by 422,000) visitors. My reputation is 10233 points. I have been awarded 1 gold, 17 silver and 39 bronze badges.

Codidact

In the fall of 2020, I joined with great enthusiasm in founding the new Codidact Q&A platform (Electrical Engineering section), where so far I have a total of 29 posts (12 articles, 3 questions and 14 answers). I made a total of 353 edits and 92 comments. I was awarded for the anniversary of the site as one of the first 50 participants with the highest rank.

Receiving recognition at the university

2015. I received my habilitation, which gave me the opportunity to collect and organize everything I did for the purposes of the learning process in the field of circuitry.

Diplomа habilitation

I developed the laboratory exercises in the new discipline "Semiconductor Elements" of the students from ITI. I gave up the ready-made setups, which hid the essence of the studied objects and used solderless prototyping boards.

Prototyping boards

Thus, the exercises were free experiments conducted by students with real elements. The experiment proved successful and continues to this day.

Investigation of the diode differential resistance - breadboard


Laboratory equipment

At the beginning of the semester (September 2015), I conducted a unique web experiment by placing this way of conducting a discussion in ResearchGate. There have been many reviews, including from celebrities like Barrie Gilbert. After that I continued to cover the conduct of the laboratory classes until now, asking interesting questions for discussion, illustrated with many photos from the laboratory exercises. The response was wide.

Later I applied this approach in the disciplines Specialized Computer Electronics, Microprocessor Devices and Digital Circuits. Since then I have been uploading the resources for the next lectures and laboratory exercises in all disciplines in GoogleDrive (in parallel with the resources of the Moodle platform).

Lab 1217 - view

Distance learning

2020. With the introduction of distance learning in the spring of 2020 (due to Covid 19 pandemic), I set about redesigning the way it is conducted in electronic form. Here is the beginning of my first video lecture, conducted with the ZOOM platform, on the subject "Specialized Computer Electronics" (SKE) of students from CSE, 3rd year, module "Computer Engineering".

In the fall of 2020, I began experimenting with distance learning by expanding my free use of the web through the Google search engine during classes. The approach turned out to be fruitful and I am still applying it.

Then I discovered a unique possibility of ZOOM for drawing not only on the "whiteboard", but also on the screen (annotation tool). I have started using it regularly to modify existing web images, by editing circuit diagrams and even "erasing" parts of them with white paint.

Tracing the current path in a simple electrical circuit

I even decided to upload the ZOOM meeting recordings to Google Photos and Google Drive (up until this point I had only used the recordings for "internal use"). This proved to be a great convenience for the students.
But the end of distance learning began to be seen, and I began to think about how to use all this experience and the accumulated video resources for the purposes of face-to-face training (as I have been using the resources of face-to-face training for the purpose of online training). I even organized a discussion with my students and they gave valuable suggestions - for example, to use our mobile phones and the "screen sharing" mode. This might be my next pedagogical experiment…

The discipline of Electrical engineering

2022. In the summer semester, I had to teach the seminar and laboratory exercises in Electrical Engineering for IT students, 1st year, in the conditions of online learning. Organizing them turned out to be a big challenge for me, even though I already had experience with three other disciplines - SCE (2004 and 2005 - album), SD (2015), MPT (2015)... but I managed to do it successfully. Already last year, I had revealed the philosophy of such an Electrical Engineering for Electronics in a special post on my blog, but then the exercises were not assigned to me.

Online exercise in Electrical engineering

However, the online training ended shortly before the end of the semester and I was able to do 2-3 very important real exercises for the students.

In the Electrical Engineering laboratory

The enthusiasm...

On 04/08/22, my employment contract with TU ended but there was a chance to continue for another six months on free contract due to the fact that I was an "outstanding teacher" who has done and wants to do a lot more for his students. The idea of this contract was great - to use my 40 years of experience as a teacher of basic circuit engineering disciplines to consistently develop, within these six months, laboratory experiments, with which in the fall I could conduct, already as a part-time teacher, the laboratory exercises on Semiconductors elements. It was about original experiments, in which circuits were built and reinvented step by step, using various didactic techniques. In this way, I revealed the philosophy of electronic circuits, got students to think about and understand the circuits under study, and tought them how that understanding happens (something I have done all these years). The idea for these experiments arose years ago, and I have carried out some of them in my classes with students, but only now I decided to develop them and describe them in detail.
I was very enthusiastic, everything was coming together great, and I got down to business - inventing, experimenting, describing, photographing, uploading to the web... Here is the end result - the six stages of the contract with links to the resources uploaded in a convenient for reading kind on my blog Circuit Stories:

The disappointment...

But... everything turned out to be just an illusion... It turned out that my contract was signed "by mistake" and they explained to me that all this was not necessary... My two most "faithful" colleagues (one of them imagine a former student of mine from the 80s and now leading this discipline!), at which I conducted the classes with exactly such technical means, gave negative opinions about what was done... and the contract was terminated. I was not even notified about it.... I was physically denied access to the lab... and under the circumstances there was no way I could teach the classes... Everything I made stayed in the lab.... and it was all over...

I never thought that after all that I have done in these 40 years at the University and left behind in the laboratories, the web and above all, in the souls and hearts of my students, I would be treated like this. 40 of my 68 years of conscious life have been spent at the Technical University in the service of what I was appointed to do as a teacher - the academic work with students. Everything I have done - publications, research, web materials, participation in scientific networks and sites, technical means, etc. has been and is intended for this purpose. To developing new materials in this direction, I have devoted most of my time in the office, at home and elsewhere. I have understood it not as a job and an obligation but as an activity that I do by vocation. In addition to this, I have shared everything I have done on web to be useful to my colleagues - teachers in the field of technical education. The most recent example of this is the above-mentioned pedagogical experiment New moments of my work with students in the conditions of online learning. Therefore, it has a methodological value not only within the country, but also abroad.

I felt a moral obligation to apologize to my students for the broken promise that we would continue with everything we had done with them last semester, and I wrote them a farewell email with links to resources in these disciplines.

The return...

So, my teaching activity with the students of the Technical University ended suddenly and unexpectedly for me. At the beginning I felt a kind of "vacuum" but then I started to feel relief because I had already started to get tired of forcefully teaching the IT students something (circuitry) that they were not interested in. Now my ideas on the web could be used by inquisitive "online students" from all over the world (including some of my former students) who were actually interested in the schemes. So I happily began to return to my creative work on the web (Circuit Idea wikibook, my Circuit Stories blog, and the ResearchGate, StackExchange, and Codidact forums). My dream is to complete Circuit Idea and bring everything I have done over the years to my Circuit Stories blog...

The "discovery"...

And here, surprisingly for me, a very real "student" appeared, who showed a desire to do interesting technical (physical) experiments. It was my seven-year-old grandson, Alex, who has only been in first grade for a month. I knew he was "far ahead with the material" because he could read and write fluently, easily solved math problems and expressed himself like an adult (that is why I jokingly call him "Professor Mechkov":-) But now he surprised me with this interest in physical experiments. Maybe I had turned him on a while ago when I gave him a set of magnets and we did various experiments with them? And maybe, I secretly hoped, there is something inherited from my passion for technology :)?

... to explain something to a 7-year-old...

And then Einstein's winged thought popped into my mind: "If you can't explain something to a six-year-old, then you don't understand it yourself." It was a really big challenge for me, after 40 years of explaining to students, to try to do it with a 7-year-old child.This made me ambitious to introduce him to a popular physics experiment the way I introduce electronic circuits to students - by developing the idea step by step, building and reinventing circuits.

I vaguely remembered from childhood a spectacular experiment with a glass full of water that did not want to pour out when we turned the glass, and I decided to start with it. Here is the post (for now, in Bulgarian) dedicated to what Alex and I did on Saturday night…


This probably piqued his interest and he expressed a desire to do more similar experiments with water. Thus arose the idea to find out how the ancient Greek scientist Archimedes was able to prove that the golden crown of the king was fake. To be honest, I had not thought about exactly what he had done to establish it either, although I often used the exclamation "Eureka!" in my circuit stories. My humble knowledge was that Archimedes dived into the tub, saw the water rise, got an idea, and ran naked screaming "Eureka!" Apparently now was the time to figure it out, explaining it to a 7 year old...

... and even to a 1-year-old child :-)



During the experiment, my youngest granddaughter, Katerina, one year old, unexpectedly got involved. I had to paraphrase Einstein's winged thought in a suitable way - "If you can't explain something to a one-year-old child, then you don't understand it yourself" :-) Well, this was already a really big challenge for my pedagogical capabilities!

Conclusion

In conclusion, I want to say that most of my conscious life has been spent at the Technical University of Sofia in the service of what I was appointed as a lecturer - teaching students. Everything I have done and am doing - publications, research, web materials, participation in scientific networks and sites, technical means, etc., has been intended for this purpose. I dedicate most of my time at work, at home and elsewhere to developing new materials in this direction. I considered it not as a job but as an activity that I did by vocation. I have shared everything I have done on the web to be useful to my colleagues - teachers in the field of technical education. So, it has a methodological value not only within the country but also abroad. Now I will continue to do the same but only on the web...

Student materials uploaded to Google Drive

ТЕ ИТИ 2022 - Electrical engineering - seminar and laboratory exercises
МПТ ИТИ 2022 - Microprocessor devices - lectures and laboratory exercises
СКЕ КСИ 2022 - Specialized Computer Electronics - lectures and labs (2022)
СКЕ КСИ 2021 - Specialized Computer Electronics - lectures and labs (2021)
СКЕ КСИ 2020 - Specialized Computer Electronics - lectures and labs (2020)
ППЕ ИТИ 2021 - Semiconductor devices - laboratory exercises
ЦМПТ АТТ 2021 - Digital and microprocessor devices - lectures

Albums of students' photos and videos uploaded to Google Photos

Електротехника ИТИ - Electrical engineering - seminar and laboratory exercises (2022 - )
МПТ - Microprocessor devices - lectures and laboratory exercises (2013 - 2019)
МПТ в лаборатория 1217 - Microprocessor devices (1216)
Basic Electronics (SCE) - Specialized Computer Electronics - lectures and labs (2004 - 2020)
СКЕ в лаборатория 1217 - Specialized Computer Electronics - labs (2016)
MICROLAB - Specialized Computer Electronics - lectures and labs (2005 - 2020)
Semiconductor lab - Semiconductor devices - laboratory exercises (2015 - 2021)

Видео записи от онлайн занятията в ZOOM, качени на Google Photos

ТЕ ИТИ 2022 - ZOOM - Electrical engineering - seminar and laboratory exercises (2022 - )
МПТ ИТИ 2022 - ZOOM - Microprocessor devices - lectures and laboratory exercises (2022)
МПТ ИТИ 2021 - ZOOM - Microprocessor devices - lectures and laboratory exercises (2021)
СКЕ 2022 - ZOOM - Specialized Computer Electronics - lectures and labs (2022)
СКЕ 2021 - ZOOM - Specialized Computer Electronics - lectures and labs (2021)
СКЕ 2020 - ZOOM - Specialized Computer Electronics - lectures and labs (2020)

ППЕ ИТИ 2021 - ZOOM - Semiconductor devices - laboratory exercises (2021)

ППЕ ИТИ 2020 - ZOOM - Semiconductor devices - laboratory exercises (2020)

ЦМПТ АТТ 2021 - Digital and microprocessor devices - lectures (2021)

Student related material on my Circuit Stories blog

General materials

Electrical engineering ТЕ ИТИ 2022

Specialized Computer Electronics СКЕ КСИ 2022

Semiconductor devices ППЕ ИТИ 2021

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