[edtechdev]

This Falstad animated circuit simulation has been the best at conceptually understanding what's going on in circuits: https://falstad.com/circuit

Click on the 'Circuits' menu to see dozens of example circuits.

One issue with the hydraulic/fluid analogy is the "empty pipe" misconception - we forget or don't know that in electrical circuits, the circuit is a closed loop. An example of this misconception is that beginners sometimes think the current "wears out" as it goes along the wire. The Falstad simulation shows a line of moving dots that move faster or slower depending on the current - a little more like a train moving in a pipe - which helps counter this misconception, although it, too, isn't perfect. As a next level, I like showing animations/simulations that show the role of charge on the 'outside' of the wire in steering current flow, as well as magnetic fields surrounding the wire.

[rdtsc]

Those are exceptional. I remember gaining really nice math and physics intuition from his "applets" years ago. Yes, those started as Java applets if anyone still remembers those.

Here are math and physics ones: https://falstad.com/mathphysics.html

I like the 2D vector field one https://falstad.com/vector (2d) and the 3d one https://falstad.com/vector3d.

Antenna simulator: https://falstad.com/antenna

Waveguide is awesome too https://falstad.com/embox/guide.html. Don't forget to pick various modes in the little square at the bottom.

If Paul Falstad comes around these parts, thank you for creating and sharing those!

[gkhartman]

I'm pretty sure this is the one that I found while in undergrad physics. That diagram helped me gain a level of visual understanding that I hadn't obtained from hobby DC circuit tinkering. I remember feeling very grateful to exist during a time when an interactive web app could show me what would have taken N hours in an electronics lab to see in years prior. Many thanks Paul Falstad.

[gowld]

A "closed" circuit is just an open circuit plus a pump (electron pump or water pump).

Open circuits work fine if there is a powerful source of electricity (like a a radio) and a sink (like the Earth), and same for water (an icy comet crashing into a cliff, making a waterfall).

An open water circuit is full of stationary water.

[stathibus]

Falstad is a really excellent education tool. I used it myself as an undergrad and as a tutor. Can't recommend it enough.