This looks great, but while one is playing with it (or, alternatively, while one has classes on electronics), it may be good to know that you do not need your

This looks great, but while one is playing with it (or, alternatively, while one has classes on electronics), it may be good to know that you do not need your browser to simulate electr(on)ic circuits: try ngspice (should be available on all operating systems where one could expect such software; Unices, Windows, Mac): it is an implementation of the SPICE simulator, but with many modifications, including scripting support (it has its own language built-in, or one can use tcl or C to control ngspice). The main difference while getting started is that one does not lay out schematics while working with nspice, rather one just describes the circuits as graphs where the edges are electronic components. It is more abstract in that sense, but I think it is closer to programmers in these ways, and it provides more power to the (programming) user. (Note that one would probably draw the graphs on paper before describing them for SPICE/ngspice.) EDIT: see https://wiki.archlinux.org/index.php/List_of_applications/Science#Electronics https://wiki.archlinux.org/index.php/List_of_applications/Sc... and, especially, https://wiki.archlinux.org/index.php/List_of_applications/Science#Electronic_circuit_simulation_and_schematic_capture_editing https://wiki.archlinux.org/index.php/List_of_applications/Sc... for other simulators. Side question: I would like to get to being able to design PCBs which I could then get produced and populated in very small quantities, just as a hobby. What are the fields of knowledge which one should approach before designing PCBs oneself? Any good books? After that, I would need to choose between gEDA and KiCAD, while the latter seems to be quite a bit more popular, gEDA's supposed design in the UNIX philosophy (as a suite of tools that the user uses through programming/scripting) appeals to me, so does somebody have any experience with gEDA to share (pros, cons, etc.)? Another question, more on-topic: could somebody clarify in what cases can we simulate electronic circuits while representing values with phasors/complex numbers? As far as I understand there are some limitations, like it is always a correct identification if all components are linear, or if the AC parts of the signals have "small" values compared to the DC parts of the signals. Am I mixing stuff up? What are some of the real world situations in which simulating with phasors breaks down?