oscillator wont simulate correctly

Circuit will not oscillate when I run a time-domain simulation. Tried simulating before and after BJT. Please let me know what I am doing wrong. https://www.circuitlab.com/circuit/696rk45e2ttn/final-project-electronics/

by maddiemueller
May 03, 2024

The period is about 500u, so, by Nyquist, your time interval must be, MINIMUM, half of it, but recommended, 10 times less, and that is a minimum.

You must run the simulation to get a few periods, since the first ones are generally different than the "steady" ones.

Next, a perfect symmetry, which is unreal in the real world, may kill any "starting" oscillation. Against that, I add an imperfection, such as, here, R3=40K and reducing it gradually until I lose the starting oscillation.

Also, check the scale. That my sounds a little bit flat even if it oscillates form minus one uA to plus one uA when displayed at the same time than 150mA

(Note that I recommend removing the timed switches, which required, uselessly, extra computation time, so I don't have to wait to see the result, at least, to get the proof of the oscillation.)

by vanderghast
6 days, 7 hours ago
Add comment...

Please sign in or create an account to comment.


No Answers

No answers yet. Contribute your answer below!


Your Answer

You must log in or create an account (free!) to answer a question.

Log in Create an account


Go Ad-Free. Activate your CircuitLab membership. No more ads. Save unlimited circuits. Run unlimited simulations.

Search Questions & Answers


Ask a Question

Anyone can ask a question.

Did you already search (see above) to see if a similar question has already been answered? If you can't find the answer, you may ask a question.


About This Site

CircuitLab's Q&A site is a FREE questions and answers forum for electronics and electrical engineering students, hobbyists, and professionals.

We encourage you to use our built-in schematic & simulation software to add more detail to your questions and answers.

Acceptable Questions:

  • Concept or theory questions
  • Practical engineering questions
  • “Homework” questions
  • Software/hardware intersection
  • Best practices
  • Design choices & component selection
  • Troubleshooting

Unacceptable Questions:

  • Non-English language content
  • Non-question discussion
  • Non-electronics questions
  • Vendor-specific topics
  • Pure software questions
  • CircuitLab software support

Please respect that there are both seasoned experts and total newbies here: please be nice, be constructive, and be specific!

About CircuitLab

CircuitLab is an in-browser schematic capture and circuit simulation software tool to help you rapidly design and analyze analog and digital electronics systems.