Circuit.js – Electronic circuit simulator on the web

Fair, but that should generally not be so restrictive that it causes a problem with "having SPICE models for actually purchasable components".

Personally I don't mind some "reddit esque" (or whatever you want to call them) comments here and there. The level of those present on HN is low anyway. They could/should be less in some cases, but they don't bother much as the majority is still mostly insightful comments or interesting discussions. Imagine a completely sterile online community without any communication side-tracked, even if it's just a tiny bit, from the informational topic. That just wouldn't feel right to me. The equivalent of a "everyone got a stick up their lower half" workplace. Yuck.

Author of the CircuitLab https://www.circuitlab.com/ (YC W13) mixed-mode (analog and digital) simulation engine here. The "core algorithm" is probably LU decomposition on a sparse matrix: https://ultimateelectronicsbook.com/systems-of-equations/#lu... .

I answered a similar question on Electronics StackExchange where someone asked about how to build a circuit simulator: https://electronics.stackexchange.com/a/394069

From a software developer perspective: lots and lots and lots of automated tests, each of which builds a circuit, runs a simulation, and makes sure we don't see any behavior regression. More lines of code in tests than in the core simulation engine or device models!

This reminds me of https://logik.land/ which was written by glittle.org. Very cool stuff!

I posted that rather quickly, so a bit more information for those who are interested (inspired by some of the comments on the thread).

I found Paul's sim by chance and really liked it because it was the first electronics sim that I had seen that was properly interactive and visual in its approach. I thought it was a great tool for building intuition about circuits. However, at a certain point it became clear that Java in the browser was on its way out, and this really needed to become a plug-in free experience if it was going to continue to be useful.

This was about the time that V8 was coming along and revoluationizing the performance of JS. Originally there was no license attached to the project, so I asked Paul if he was OK in me trying to port it to run on JS using the GWT framework. He was fine, but said he'd done old experiments with some of his other sims and found that JS wasn't performant enough, but with the strides in JS performance I was more optimistic.

I took the Jave code and commented just about everything out to get a minimal implementation of the standard LRC circuit just to see the performance. Once I was comfortable with that working I started adding every feature and every component back. Most of the work was replacing the Java graphics primitives with the equivalents from GWT.

Once the initial version JS version was out I did quite a lot of work mostly on UI features, especially the 'scopes. They were rather weak in the original and still not as good as I would really like, but much improved.

I have thought about monetizing and extending with EDA features, socials, etc. but its never been enough of a priority to do it. I kind of like its simplicity as it is.

It has been used a lot in education and a couple of teachers have contributed to the code to support their uses in classrooms.

It's kind-of amazing that it still has a very distinctive niche that nobody else has really gone after in quite the same way. I think a lot of that is because Paul's original vision and work on the Java version was so good.

There is a bit more context and some tutorials here: http://lushprojects.com/circuitjs/