Roberto Perez-Franco

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The masterpiece of TI-89 programming.

— Alex Astashyn EE+CoE+CoS major, Polytechnic University in Brooklyn, New York, USA (Born in Russia)


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. Keep up the good work...

— Nikolaos Trichakis EE major, Aristotle University of Thessaloniki, Greece


Brilliant work by Mr. Pérez-Franco! Check it out!

— Arne Harstad EE major, Norges tekniske-naturvitenskapelige Universitet, Stavanger, Norway


Congratulations for your program: it's simply fantastic. Symbulator is worth the cost of a TI-89!

— Pier Giorgio Raponi Engineering student, Pisa, Italy


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 CA, USA


Symbulator is a wonderful tool.

— Reinhard Willinski EE major, Germany


It runs beautifully in TI-89.

— Harold Martínez CoE major, City College, New York, USA


I find Symbulator to be a phenomenal program. You did a great job. The more I use it, the more I want to use it.

— Michael EE/CoE student, San Diego State University, USA


Totally awesome! Thanks a million.

— Chris Spencer EE major, University of Florida


You've made an excellent program. Symbulator is really the best circuit simulator ever made for a calculator.

— Rui Sebastiao EE major, University of Coimbra, Portugal


Your program is absolutely great, and I use it all the time, not without enjoyment. (...) This is a great program, Roberto, and I hope you continue developing it.

— Carmel Nachmany EE major, Ben-Gurion University of the Negev, Israel


Symbulator is a great tool to check answers.

— Brad Norman EE junior, Montana State University, Bozeman, US


Congratulations for your software Symbulator. It's great!

— Eduardo Silveira EE major, Brazil


Thanks for an exquisite, free program!

— Chandler Sorenson Computer Engineering, University of Arizona, Tucson, US


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. Again, good job!!

— Jim Wachtel EE, Process Control & Electrical Co., St. Louis, Missouri, USA


Your programs are the best thing I have ever seen on the TI website. I can tell that you are making a lot of engineering college students happy.

— Ade George EE major, Morgan State University, USA


I love this program! Trying to learn how to use it has increased my knowledge of actual circuit analysis, which helps me out in the long run. Your software is great. I'm taking my first ELEN class and this software not only confirms my work, but helps me understand the circuits as well.

— Josh Earley Computer Engineering major, Texas A&M University, USA


I wanted to tell you that I've been trying out a few programs on my calculator recently and this is by far the most impressive. I am studying to be an Electrical Engineer and while I enjoy solving problems by hand, this really impressed me as a way to check my work! I stayed up late last night just seeing if I could solve problems from my old Circuits text book.

— Logan


I will, one day in the near future, buy a TI-89 just to use your Symbulator.

— Ron Ross


This program is the premiere circuit solver for calculators. Yes, there are others, but none are better. This program is similar to SPICE or PSpice in the way it is used, and it is even easier when it comes to dependant sources and biport simulations. Once a circuit is solved, it has ALL the information the user would want: node voltages, element currents, element power usage, voltage drops across elements. It solves symbolically, unlike almost any other circuit simulator (even PC based). This program is, hands down, the best program for circuit analysis that I have seen. Big circuits can be slow to solve, and can run the calculator out of memory. Work-arounds are out there, including tools for breaking the circuit into groups of Thévenin or biport equivalents. I could not possibly praise this program well enough. It's hard to believe that Mr. Perez-Franco is letting the world use his fantastic program free of charge. Excellent job!

— Jay Myers EE major, University of Texas at Arlington, Texas, USA


I have been using your wonderful program for about four months now. The freedom it affords is amazing. (...) I use Symbulator extensively for analysis and design in EE and find it easier to use (and really a better learning tool because you must understand what you are doing) than PSpice. I am truly impressed with the efficiency of the program and the simple fact that I have had no problems with the program itself.

— Douglas Fisher BioMedical Eng, Math Wright State University, Ohio, USA


I think your program is absolutely great. (...) Your Symbulator is the neatest thing to have around. (...) Good job, Roberto. (...) What a great program by such a gentleman.

— Tim Hutcheson BS in Comp Sci, Institute for Human and Machine Cognition, Florida, USA


Let me congratulate you on Symbulator. Amazing job! I have EE200 and EEPro, but your app seems to far surpass the capabilities of these two apps.

— Ralph McCarthy EE major, Minneapolis, Minnesota, USA


I think your program is one of the best programs out there in the community, and in my personal Top 10 chart, it's in the top. It was the reason I bought the ti-89 for in the first place. I have distributed the Symbulator to everybody in my class and they've been enjoying it a lot when solving EE problems.

— Melnic Atrav EE major


Hey, hats off to the programmer of this one, and for the generosity to share it so freely. I guess it's too bad I bought EE*Pro for $50 less than a week ago, huh?

— Brandon Newsom High school student, Newport News, Virginia, USA


A million thanks for your program. You don't know how fine I feel every time I solve a circuit with paper and pencil, and I get the same answers I got with Symbulator. It is much easier to learn this way. Truly, I believe you deserve a mention in circuits books.

— Gabriel Florit EE major, Dordt College, Sioux Center, Iowa, USA


Thank you for your brilliant program. (...) I have used your program quite a bit throughout my studies. (...) I have to commend you on such a comprehensive and impressive program. In my mind, it is the most important program to have on a calculator for those taking EE courses. (...) Thanks for your time, and for your Symbulator, Roberto.

— Albert Meng System Science Mathematics major, Washington University, St. Louis, USA


It is a great way to check your answers in homework and on a test. Try it out for yourself, that is the only way you will figure out what Symbulator is capable of. I am still amazed about how well Roberto's program works...

— Al Charpentier EE major, Pennsylvania State University, Pennsylvania, USA


We all know about SPICE and what a lifesaver it is in our design projects, but the learning curve has always been a steep one. In my quest for the best EE applications for design and analysis, I came across Roberto Perez-Franco's Symbolic Circuit Simulator (Symbulator) for the TI-89. I have been using Symbulator for almost a year now, and believe me, it is a must for every electrical engineering student.

Perhaps the most startling aspect of Symbulator is its fully symbolic implementation. Answers are left in terms of variables instead of being converted into numeric approximations. This allows for easier analysis, interpretation, and plotting. If you're taking Dr. Gedney's Circuits II course, Symbulator will save you every time. Dr. Gedney is infamous for assigning problems which do not have solutions in the textbook. With Symbulator, the solution is only seconds away, and a better understanding can be obtained by reverse-engineering the problem so you know you understand the correct solution.

Since the interface to Symbulator is similar to SPICE, once you know one, you can use both. For EE 211 and EE 221, Symbulator actually works better than SPICE because you get the results symbolically. Once you use Symbulator you'll see what everybody has been talking about.

If you're not using Symbulator, you're working too hard.

— Chris Riegel EE+CoE major & President of the IEEE student chapter in his U., University of Kentucky, Kentucky, USA


I am really satisfied with the program. (...) I have greatly enjoyed using your program and have convinced most of my classmates to use it also. (...) I am on my third year in EE and have used Symbulator since day one. I am still using it on a regular basis.

— Nevin McChesney EE major, University of Kansas, Member of the US Navy, USA


I would like to thank you for creating such a great tool for EE analysis. I especially appreciate that you released it for free.

— Jeff Bach EE & Music major, University of New Mexico, New Mexico, USA


I'd like to congratulate you on the success of Symbulator for the TI-89... it seems to be used and appreciated by many students.

— Paul King Texas Instruments, Texas, USA


Perez-Franco's Symbulator and Frederiksen's DiffEq programs are two musts for any serious TI-89 user!

— Daniele Martini EE major & author of S2S plug-in for Symbulator, Florence, Italy


The TI-89 opens up all kinds of opportunities for useful programs, the Symbulator suite being a great example.

— Michael Rans E+CSc major, Oxford University, London, UK


When I start my next circuits course and my first Controls course in the fall, I know Symbulator will be my best friend once again, especially with all of the improvements you have made.

— Charles Ware EE major, Ohio State University, Columbus, Ohio, USA


Just want to say that I admire your work. (...) I enjoy developing programs for my TI89 that help solving my day by day problems. That's why I admire your work.

— Sergio Coelho Engenharia Electrotecnica, Faculdade de Engenharia da Universidade do Porto, Portugal


Me and all of my friends at the University of Texas in Arlington think the circuit simulator is great. Thank you for all of your hard work on this program.

— Jeffery Allen EE major, University of Texas at Arlington, Texas, USA


I'm using Symbulator for only two weeks now and I can say that I am in a way addicted to your program. It is really the best software you can get for a calculator on the field of Electrical Engineering. When I show it to my colleagues at the faculty, I know that it will spread in Slovenia too. (...) Thanks again on this wonderful program.

— Matic Hibernik EE major, University of Ljubljana, Slovenia


Congratulations for Symbulator program. It's really good!

— Bernardo Merino Bermejo EE major, Escuela Universitaria de Ingeniería Técnica, Madrid, Spain


I really appreciate this program and I'm sure many students will as well. I hope that now all other programmers would try to create useful science programs.

— Vic Fischer Physics+CoE+EE major, Université Jean Monnet, France


I just loaded symbulator onto my calc last night and I am liking it a lot.

— Samuel Nyall Stearley


Your programs are great and useful for all students with a good calculator.

— Michael Preuhs EE major, Universität Gesamthochschule Siegen, Germany


Thanks for coming out with such a great program.

— Abhishek Shrestha CoE Sophomore, Western Michigan University, USA


You can be really proud of Symbulator!

— Kamil Malinski EE major, Technical University, Vienna, Austria


Thank you very much for all your hard work on Symbulator — nice job!

— Doug Burkett EE major, Eaton, Ohio, USA


Thanks for carrying me through more than two years of EE studies.

— Thomas Schallhofer Northest University of Applied Sciences, Flensburg, Germany


Thanks for doing this program!

— Thomas Knoblauch EE major, ETH, Zürich, Switzerland


Wow! Now I can do Bode Plots!!

— Damion Hadcroft ME major, Adelaide University, Australia


I'm sure this program will prove to be quite an asset.

— Andrew Hockman EE+CoE major, Missouri, USA


It is really simple. At the same time, it's a very useful, great program.

— Andrej Bencúr EE major, Technical University of Ostrava, Czech Republic


I love the software, it helps me out in the lab quite a bit.

— Eric EE major, University of Dayton, Ohio, USA


Thank you so much for letting me get this program. It has been wonderful and I appreciate all of Roberto Perez-Franco's hard work.

— Jared Whitaker EE major, UAA


I want to thank you and congratulate you as well for such a nice and useful program.

— Dan Safoory EE major


Thanks for your work. Symbulator is fantastic! (...) God has really blessed you with quite a talent for solving difficult problems. (...) I am not going to take another exam without it...

— Jake Adams ME + EE student


I love your program and I greatly appreciate all the hours and hard work you have invested. (...) I must give you partial credit for placing 2nd in my circuits class and getting a perfect score on my final exam. My advisor is no longer telling me I may want to reconsider my choice of major from electrical engineering to something more suited to my advanced age of 41.

— Annie EE major


I must say that this program looks extremely tight and well tuned. You should be hugely commended for your abilities! Great job and keep up the excellent work!

— Neel EE major


These have been great learning tools and helped reemphasize what school teaches. I have to use these tools to help me better understand rather than just mindlessly answering the questions. Thanks to this calculator, your programs and lots of hard work and studying, I actually survived my "Advanced Circuit Analysis" class, with an "A" to boot. It was a class from hell!

— Jackie CoE+EE major


Roberto, you are doing a good job for TI and EE students that use TI89's and 92+'s. Keep up the good work.

— JLA

On Symbulator Q

Roberto, thank you for your diligence and hard work in creating and perfecting a GOOD circuit simulator. (Not to mention FREE). The use of Symbulator has improved my learning of electrical circuits.

— Nevin McChesney, on Symbulator Q EE major, University of Kansas, Member of the US Navy, USA


Thanks, again. This is an excellent program and I am very interested in seeing the book you are writing for Symbulator Q.

— Eric Wierwille, on Symbulator Q


I want to thank Roberto Perez-Franco for writing such a wonderful program — the Symbulator. Spending so much development time on the home page and software, and not charging a nickel for it, makes you a real hero. That kind of thing brings a tear to my eye! Thank you!

— Bez, on Symbulator Q


Thanks for the program. It is a true gem, and a free one at that...a true rarity!

— Dorian, on Symbulator Q


I must say, Rob, that once again you've outdone yourself. I hope that this isn't the last time, and look forward to more genial programs from you. Thanks for letting us enjoy the Symbulator for free. It's not often that great programs come free. You, my friend, are an example to follow.

— Anonymous poster @ TI DG, on Symbulator Q


And the Oscar for Best Program of the Year for a TI calcs goes to... (drums) Symbulator Q, by Roberto Perez Franco. Huray! Huray!

— Anonymous poster @ TI DG, on Symbulator Q

On Symbulator 4 (Impala)

This program is one of the major TI programming accomplishments, and in fact one of the most significant programs for any calculator. (...) Until I started the (Impala) testing, I did not realize just how powerful Symbulator really is. (...) Symbulator makes it possible to solve every homework and test problem, without knowing much more than how to enter the circuit in the matrix form! (...) I have been both playing with calculators and using them professionally for over twenty years. I am quite aware of their capabilities. And I think that Symbulator is the most amazing end-user calculator program that has ever been accomplished. I am grateful to you for having done this work, and for having improved Symbulator so enthusiastically. You know that Symbulator is good enough to be a for-pay program, yet you gave it to us for free. That means a lot to me.

— Doug Burkett, on Symbulator 4 (Impala) EE major, Eaton, Ohio, USA


I'd like to thank Roberto for his effort in releasing Symbulator 4 (Impala). It's really an incredible program.

— Farooq Ahmed Weshah, on Symbulator 4 (Impala) EE major, Yarmouk University, Jordan-Salt, Jordan


I was going to sell my TI-89 because I didn't see any use for it. But this new program by Roberto made me want to try this program out. Congratulations for your work!

— Marcelo, on Symbulator 4 (Impala) EE senior, Canada (born in Chile)


Roberto, I've been enjoying your program for over a year and use it regularly. It has made my EE studies much easier over the years. (...) Thanks again for a superb program, which is the reason for which I chose TI-89.

— Gordon, on Symbulator 4 (Impala)


Another triumph in BASIC programing for 68K calculators. Awesome! I can't describe it any better.

— Captain Ginyu, on Symbulator 4 (Impala)

On the IEEE Award in 2000

Congratulations on receiving the IEEE award — I believe it is very much deserved. It makes me smile to see you rewarded for your hard work and dedication to Symbulator and the TI community.

— Paul King Texas Instruments, Texas, USA


Many, many congratulations, Roberto! Passion and intelligence will *always* beat greed and narrow vision.

— Doug Burkett, on the IEEE Award EE major, Eaton, Ohio, USA


Congratulations, Roberto. Symbulator is a masterpiece worthy of the best programs out there, free or otherwise. And the fact that it is free speaks volumes about its creator. Peace be with you always.

— Jake Adams, on the IEEE Award ME + EE student


Congratulations, Roberto!!!

— Dave Conklin, on the IEEE Award Professional TI-89 programmer


Ha! Some wise man finally discovered what so many 'meere students' have known for some time. It's so good to see some recognition for you. You deserve it.

— Jay Myers, on the IEEE Award EE major, University of Texas at Arlington, Texas, USA

On Symbulator 3 (Expert)

Once again you did a great job and I'm sure I'm not the only one who is sending you a "Thank you very much, Roberto. Our EE-life is a lot easier with your Symbulator :-)".

— Kamil Malinski, on Symbulator 3 (Expert) EE major, Technical University, Vienna, Austria


Once again, good work! I thought Symbulator was pretty much a finished and polished product and now you pull new tricks out of your sleeve! (...) Symbulator has been a very valuable tool for me. By the way, I recently passed my Professional Engineering exam. Symbulator allowed me to check some of my answers. A pretty hefty dual op-amp circuit was one I checked...

— Jim Wachtel, on Symbulator 3 (Expert) EE, Process Control & Electrical Co., St. Louis, Missouri, USA

Comments in Spanish

Thank you for making life easier for all of us who study Electrical Engineering. Also, I have many friends who are grateful for your contribution. Thanks!

— Alvaro Baeza Electrical Engineering student, Pontifical Catholic University of Chile, Santiago, Chile


I want to congratulate you on such an ingenious program. We use it a lot at the University of Central Florida, in Orlando. (...) In my group, I think about thirteen of us use Symbulator. A friend from another class passed it on to me, and I know that many of his classmates were using it. Another group uses Work Bench a lot, and others use PSpice—which I haven't experimented with much, since I haven't been able to get hold of it. But those who use all three programs always say that yours is the easiest and fastest to use. (...) The Spanish documentation of your program is fantastic.

— Fernando Blanco 4th-year Electrical Engineering student, University of Central Florida, Orlando, USA


I want to congratulate you on the program. It richly deserves the IEEE award. I am sure that once I have installed this program I will lose my resentment toward that circuit analysis that I find so tedious. Thank you very much, and congratulations again! (...) I am delighted with the program. The manual is perfectly well explained.

— Jorge Treviño Electronic Engineering student, Universidad Iberoamericana, State of Mexico, Mexico