Ultimate Electronics
Browsing randomly through the content I've noticed that you're discussing impedance, capacitive/inductive loads and transitional states in the DC section (and also fairly early in it). I think it'd be way easier to grasp for someone new to this if it was a section on its own, and after the AC circuits are already well explained. To tackle this properly mathematically and understand it well you need to understand a lot of very abstract things like impedance, phase shifts and complex numbers very well, and IMHO that's much easier to explain on a stable state AC circuits, and then apply that knowledge on the on/off transitions too.