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JavaScript Circuit Simulator (lushprojects.com)
139 points by jcr on July 16, 2015 | hide | past | favorite | 22 comments



The original is here: http://falstad.com/circuit

He already swapped out the old java version with this same javascript (GWT-based) one.

There are several other good simulations on that site, too, and many other good animated physics simulations here: http://phet.colorado.edu/

And for those asking what's the use - there's a lot of research on the PHET simulations about their benefits for learning. I myself used Falstad's simulation in my dissertation. Students who just finished their first circuits course used this sim and learned stuff in minutes that they hadn't learned all semester, like what happens when you add a capacitor to a DC circuit, or the difference between capacitors and inductors in an AC circuit, and the effects of changing capacitance, inductance, and resistance in a circuit. In a regular circuits class, you can get by with just memorizing equations, but this simulation helps you understand what the equations mean and what is actually happening in the circuits you learn about.


There is a nice digital logic simulator called TKGate (http://www.tkgate.org/) which is good for learning. Not web based however.


I've used Paul Falstad's Java circuit simulator a lot. This is a very good port of it. Pretty cool.


Very cool. Check out http://CircuitLab.com too



To be honest, I prefer the original java version over the html5 version. It uses less resources, and doesn't cause my browser to crawl while it's running. The java version starts chugging on my laptop at about 20 transistors, this chugs with a third that many. Also, the java version had a zip file you could download to use it without being connected to the internet, which this one doesn't.


I'm unsure of why you got down-voted. Your experience is your own, and of course you're entitled to your own opinion.

With that said, I haven't seen the poor performance you described. Have you tried another browser? Or a newer version (if any) of your browser? Have you tried it with a separate browser instance without tons of tabs open? If you continue to have issues, report the performance problem on the Github repo and include full browser version and system info.


Here's a breadboard simulation in Javascript:

http://concord-consortium.github.io/breadboard/build-a-circu...

It's currently much simpler, supporting just resistors, inductors and capacitors, but it's very useful for teaching students electronics.


Adding http://www.partsim.com as well


Very nice! I like the visualizations of the current, power, etc.

I was looking at the astable multivibrator, and I'm just wondering why the transistors turn "red" when there is no current flowing through them (when the visualize-power option is on).


The colors represent voltages (green is positive, red is negative). When (for example) Q1 switches on, its collector voltage goes low and since the voltage across C1 can't change suddenly, that means Q2's base voltage becomes negative.


This is not javascript, but Java using the GWT.


GWT converts Java to javascript.


While true, the sourcecode is still in Java. The reuslting execution code is in javascript, but not meant for human consumption.


Can somebody explain why this is valuable? I'm not sure I understand why you would want to visualize a simple current flow through circuits in a webpage rather than a static display showing expected current flow?

I'm not used to building circuits, and don't want to be the guy saying "who cares", I'm truly trying to understand the value.


When you have active components it really helps understand how they evolve over time. For example, I gained a lot from it when I was building basic logic gates from transistors.

If you just want an answer, sure, look it up. If you want to develop understanding and learn electronics, then this helps. It's aimed at students.


The original Circuit Java-App was incredible useful to me during the Electronics course and while designing basic analog circuits. It's basically a SPICE for noobs.


To understand circuits, and to test them without building them. Thought that was obvious.


Does anyone know if this sort of simulations are still based on a Modified Nodal Analysis?


As someone learning first principles, this is great stuff and super helpful!


Porting something and adding ads is not cool.


  > This application was developed, with permission,
  > from the Java circuit simulator by Paul Falstad.
Original author approves? Check.

  > Thanks to the kind permission of Paul Falstad 
  > the source project for this version of the 
  > application is now available on GitHub under a 
  > GPLv2 license.
  >
  > https://github.com/sharpie7/circuitjs1
Released source code for modification? Check.

Denigrating the hard work of others is not cool, especially when they make it freely available to others.




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