Falstad Math and Physics Simulations

(falstad.com)

69 points | by pykello 1 day ago

10 comments

  • peterus 20 hours ago
    He also made circuitjs, a very useful circuit simulator which I regularly use for prototyping. It lets you modify and probe elements in real time unlike spice simulators, so it is faster to modify a design in it.

    I use spice simulators to check the final design since sometimes circuitjs can have instability issues in complex circuits involving stuff like the nonideal op amp.

    https://www.falstad.com/circuit/circuitjs.html

    • gregw2 19 hours ago
      He also wrote zsh ( https://en.wikipedia.org/wiki/Z_shell ) as a sophomore in 1990, moved onto other things a few years later, and a couple decades later in 2019 it became the MacOS's default shell.
      • ipdashc 10 hours ago
        That's wild. I knew he was the circuitjs guy which is impressive on its own, and vaguely knew of the other simulations as well, but writing zsh as an undergrad... Wow
    • quaintdev 19 hours ago
      I remeber using this when it was Java applet. Now he has converted everything to JavaScript for everyone to use. What a legend!
  • stared 16 hours ago
    This is pure gold, especially the rippld tank, 1d quantum mechanics, and the circuit simulator.

    I cited it as one of the remarkable steps in the history of educational simulations, https://doi.org/10.1117/1.OE.61.8.081809, figure 2 (a broader overview in https://p.migdal.pl/blog/2024/05/science-games-explorable-ex...)

  • sras-me 23 hours ago
    Reminds me of this [1] I made back in 2005 in Flash action script, thankfully bought back to life by Ruffle [2].

    You can fix the ends of the string by pressing space. When both ends are fixed, you can you can drag the beads and release them.

    No big deal, but hey I was quite happy with myself back then..

    [1] https://www.newgrounds.com/portal/view/267616

    [2] https://ruffle.rs/

    • andai 21 hours ago
      Oh this is great. You ever play SodaPlay?
      • sras-me 18 hours ago
        Thanks!

        >You ever play SodaPlay?

        Never heard until now. Looks interesting. Thanks for sharing, but is it available now?

  • amelius 18 hours ago
    This is a nice one to play with:

    https://www.falstad.com/rendezvous/

  • stared 15 hours ago
    Does anyone know what are Paul Falstad’s project right now?

    (I haven’t seen any new. Not sure if perfect things do not need fixes, or some switch to another field, or a burnout, or he has ascended to godhood - out of a few options.)

  • sprinkly-dust 18 hours ago
    I have fond memories of fiddling with the wave simulations on this website during high school!
  • peter_d_sherman 4 hours ago
    I really like this one, for some strange reason:

    https://www.falstad.com/embox/

    >"This java applet demonstrates standing electromagnetic waves in a 3-d rectangular box, or cavity resonator."

    Maybe it's the idea that waves can carry slower frequency secondary waves, the idea that fields can carry slower frequency secondary fields, the idea that EM space itself can be stressed in a number of dimensions, and that these stresses, (depending on waveforms and modes of oscillations) could give rise to even smaller regions of stronger, localized (yet time/period/frequency dependent!) stress... much like waves in the ocean... to use a simple analogy... but this app really shows us what's possible...

    Anyway, this page of apps is a must-have resource for any Physics or Engineering student... A+++++ !

  • montag 21 hours ago
    Legendary
  • narsonika 14 hours ago
    this is so cool, thanks for sharing!
  • songhonglei1985 17 hours ago
    [dead]