Roll the credits
If you are interested in the people behind Symbulator, here's who made it and who helped, plus some acknowledgements. And some glowing reviews of Symbulator.
About the author
Both Symbulator and this documentation were made by me, Roberto Perez-Franco. I started working on it in April 1999, as an engineering student at the Technological University of Panama (Universidad Tecnológica de Panamá) in Azuero. An early version won first place at the IEEE Student Paper Contest for Latin America in 2000, and version 5 (also known as Symbulator Q) served as my graduation thesis in January 2001.
Roberto in 2000, with a TI-89
The first five versions were written between April 1999 and January 2001. The sixth came a dozen years later, in 2013, while I was a researcher at MIT. The seventh and eighth a decade later, in 2023, and the ninth in 2026.
What Symbulator did for me
Thanks in great part to Symbulator, I landed my first job, received a Distinguished Alum award from UTP in 2008, and won a Fulbright Scholarship that took me to a Master of Engineering and later a PhD in Engineering Systems at the Massachusetts Institute of Technology. MIT then hired me, and I lived in Boston for almost twelve years. I now live in Melbourne, Australia. You can say that writing Symbulator changed my life. In a way, I think, when I am no more, Symbulator will preserve a part of my mind as it solves circuits for new generations, the same way a composer lives in the tunes or a writer in the words they conceived.
Dedication
Two people made Symbulator possible, with their love and support.
The first is my wife Monica, who had the patience to live with a cyborg for all the years my mind was focused on coding and documenting. Mi reina, my attention was elsewhere, but my heart was always with you.
The second is my late father Tito, who invested time and money in my education and bought me every gadget and widget I needed or wanted for my studies, with a blind faith that one day something good would come of it. I'm happy to know that I made you proud, Dad, and I miss you every day.
How to reach me
If you liked Symbulator, let me know. My email is my given name, then my last name with a hyphen, as a dot-com address, like so: rxxxxxx@pxxxx-fxxxxx.cxx
Acknowledgements
Human collaborators
Over the past decades, many people have made Symbulator better through their suggestions and corrections, on both the software and the documentation. Many were complete strangers at first and became dear friends through our exchanges.
Among them are: José Vega (Panama), Tim Hutcheson (USA), Lars Frederiksen (Denmark), Joe Riel (USA), Arne Harstad (Norway), Erwin Baert (Belgium), Charles 'Chuck' Ware (USA), Doug Burkett (USA), Reinhard Willinski (Germany), Kamil Malinski (Austria), Jake Adams (USA), Daniele Martini (Italy), Rozgonyi Szabolcs (Hungary), Michael Rans (UK), Alex Astashyn (Russia), Al Charpentier (USA), Nevin McChesney (USA), Ivan Oro Yu (Panama), Pepe Iborra (Spain), Dave Conklin (USA), Carlos Perez Ortega (Chile), Qifan Wang (China) and Antony García (Panama).
My thanks to all of them.
Technology
Symbulator 9 runs on Python and is powered by the algebraic capabilities of SymPy. I am thankful to the creators of such wonderful open-source software, and to the maintainers who keep their development going. I am proud to honour the open-source community by making Symbulator free and open-source software, from 2026.
AI collaborator
I also want to acknowledge that porting Symbulator to Python/SymPy, creating its interface and websites and updating its documentation, would not have been possible without the coding prowess of Anthropic's artificial intelligence assistant. Claude allowed me to do in two weeks something that I was unable to find the time to do in two decades: to port Symbulator to Python.
Problem credits
To make this book useful to actual students, the problems were chosen from widely used textbooks on electric circuit analysis, and their circuit diagrams are reproduced here as they appear in the source.
| Code | Textbook |
|---|---|
| AS2 | Fundamentals of Electric Circuits (2nd ed.), Charles K. Alexander and Matthew N. O. Sadiku, McGraw-Hill, 2004 |
| AS5 | Fundamentals of Electric Circuits (5th ed.), Alexander and Sadiku, McGraw-Hill, 2013 |
| AS7 | Fundamentals of Electric Circuits (7th international ed.), Alexander and Sadiku, McGraw-Hill, 2020 |
| B11 | Introductory Circuit Analysis (11th ed.), Robert L. Boylestad, Pearson – Prentice Hall, 2007 |
| Bo2 | Elementary Linear Circuit Analysis (2nd ed.), Leonard S. Bobrow, Oxford, 1987 |
| HK5 | Engineering Circuit Analysis (5th ed.), William H. Hayt Jr. and Jack E. Kemmerly, McGraw-Hill, 1993 |
| NR11 | Electric Circuits (11th ed.), James W. Nilsson and Susan A. Riedel, Pearson, 2020 |
| RM3 | Circuit Analysis: Theory and Practice (3rd ed.), Allan H. Robbins and Wilhelm C. Miller, Thomson – Delmar Learning, 2004 |
| TR5 | The Analysis and Design of Linear Circuits (5th ed.), Roland E. Thomas and Albert J. Rosa, Wiley, 2006 |
For the purpose of teaching students how to use Symbulator, these diagrams are reproduced under the principle of fair use. No copyright infringement is intended.
Praise received
Over the past quarter of a century, the words of encouragement I received from users of Symbulator were my incentive to keep working on it. Here is a little of that precious collection.
The masterpiece of TI-89 programming.
— Alex Astashyn, EE+CoE+CoS major, Polytechnic University, Brooklyn, New York, USA
Symbulator is and always will be the best program for TI-89/92/V200.
— Charles Ware, EE major, Columbus, Ohio, USA
Roberto, your program Symbulator is by itself a reason to buy the calc. It's a masterpiece of programming.
— Pepe Iborra, Telecommunications, Spain
The program is really a masterpiece. It gives you everything you need, very accurate, very fast. It's really what every Electrical Engineer dreams of. It's so easy to use and it does everything! DC, AC, Transient analysis, Thévenin, Bode plots… everything! I'm really amazed.
— Nikolaos Trichakis, EE major, Aristotle University of Thessaloniki, Greece
I wish I had it while going through school.
— Joe Riel, BSEE, creator of Syrup (a symbolic circuit simulator for Maple V), University of California, Irvine, USA
Congratulations for your program: it's simply fantastic. Symbulator is worth the cost of a TI-89!
— Pier Giorgio Raponi, engineering student, Pisa, Italy
You've made an excellent program. Symbulator is really the best circuit simulator ever made for a calculator.
— Rui Sebastião, EE major, University of Coimbra, Portugal
Symbulator is probably the most useful program ever made for a TI calculator. I am an electronics student and even paid for the EE*Pro software, yet I find myself using Symbulator more because it is much better at what it does.
— Josh Cunningham, electronics major
Symbulator, by far, has been the best tool for EE I have come across yet. […] It is truly an impressive piece of work. You should be proud. It certainly is helping me to focus on my studying of EE instead of trying to remember all the math.
— Jim Wachtel, EE, Process Control & Electrical Co., St. Louis, Missouri, USA
Licence
Symbulator has always been free of cost, and always will be. From June 2013 it was offered under a Creative Commons BY-NC-SA licence. Since 2016 it is open source under the MIT licence, which supersedes it. If you want to port it to another platform, you are free to do so, provided the copyright notice and the attribution of authorship travel with it.