9 ms·

JavaScript Circuit Simulator

139 points by jcr 11y ago

moron4hire 11y ago
I've used Paul Falstad's Java circuit simulator a lot. This is a very good port of it. Pretty cool.
amelius 11y ago
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).
- Thorondor 11y ago
  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.
TheLoneWolfling 11y ago
Porting something and adding ads is not cool.
- archgoon 11y ago
  > 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.
sharpercoder 11y ago
This is not javascript, but Java using the GWT.
- Grindr 11y ago
  GWT converts Java to javascript.
  - sharpercoder 11y ago
    While true, the sourcecode is still in Java. The reuslting execution code is in javascript, but not meant for human consumption.
borski 11y ago
Very cool. Check out http://CircuitLab.com http://CircuitLab.com too
pedalpete 11y ago
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.
- NamTaf 11y ago
  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.
- Jdam 11y ago
  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.
- IshKebab 11y ago
  To understand circuits, and to test them without building them. Thought that was obvious.
benschrauwen 11y ago
Check out http://circuits.io http://circuits.io
Sanddancer 11y ago
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.
- jcr 11y ago
  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.
edtechdev 11y ago
The original is here: http://falstad.com/circuit 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/ 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.
pkaye 11y ago
There is a nice digital logic simulator called TKGate (http://www.tkgate.org/ http://www.tkgate.org/) which is good for learning. Not web based however.
SamSam52 11y ago
Here's a breadboard simulation in Javascript: http://concord-consortium.github.io/breadboard/build-a-circuit.html 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.
proee 11y ago
Adding http://www.partsim.com http://www.partsim.com as well
shostack 11y ago
As someone learning first principles, this is great stuff and super helpful!
freethinky 11y ago
Does anyone know if this sort of simulations are still based on a Modified Nodal Analysis?

139 points by jcr 11y ago

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

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).

Thorondor 11y ago
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.

TheLoneWolfling 11y ago

Porting something and adding ads is not cool.

archgoon 11y ago
> 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.

sharpercoder 11y ago

This is not javascript, but Java using the GWT.

Grindr 11y ago
GWT converts Java to javascript.
- sharpercoder 11y ago
  While true, the sourcecode is still in Java. The reuslting execution code is in javascript, but not meant for human consumption.

borski 11y ago

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

pedalpete 11y ago

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.

NamTaf 11y ago
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.
Jdam 11y ago
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.
IshKebab 11y ago
To understand circuits, and to test them without building them. Thought that was obvious.

benschrauwen 11y ago

Check out http://circuits.io http://circuits.io

Sanddancer 11y ago

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.

jcr 11y ago
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.

edtechdev 11y ago

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

pkaye 11y ago

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

SamSam52 11y ago

Here's a breadboard simulation in Javascript: http://concord-consortium.github.io/breadboard/build-a-circuit.html 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.

proee 11y ago

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

shostack 11y ago

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

freethinky 11y ago

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