Also, there's an applet available for free with (I assume) similar functionality, by the same author:
<a href="http://www.falstad.com/circuit/" rel="nofollow">http://www.falstad.com/circuit/</a>
Hi, I'm the author of the app and a fellow startup nerd. I'm very happy to see my app listed on here. I was at the first startup school in Boston, any of those old timers still here? :-)