Electronics

I find the study of electronics to be somewhat frustrating. Maybe things would have been different if I'd been CmpE or EE, but I could find no real axiomatic treatment of the material. You've got QED (largely irrelevant save to confuse), and classical emag (magnets end up being rather less important than thought), and circuit laws (lots of these), and rules of thumb, and there's no great taxonomy of components, and the people on the forums are mostly braindead. So I'm taking notes here.

Charge

• The electron-like leptons (i.e. not the neutrinos), the W^± bosons, and all quarks carry an intrinsic electric charge.
• In a normal environment, electrons and protons carry a charge, equal in magnitude and opposite in sign, neutrons do not carry a charge, and everything else that might carry a charge (muons, taus, electron-like antileptons, some mesons, heavy quarks, W bosons) is vanishingly rare (and decaying very soon).
  • Photons do not carry a charge, but they do carry energy, and are the mediators of the electromagnetic interaction.
• At the atomic scale, one need deal with quantization of angular momentum, and solve for lowest energies with the Schrödinger equation, and the electromagnetic interaction is described by QED, and the Heisenberg principle applies. Suffice to know that electrons do not slam into the nucleus.
  • Most of the time. Electron capture sees an electron combine with a proton, yielding a neutron and an electron neutrino, but this is actually a weak interaction, not an electromagnetic one! The electron exchanges a W boson with an up quark in the proton, changing it to a (heavier) down quark (and ν_e), but reducing total energy of the bound system.
• Despite the fact that at larger scales:
  • Charges of equal sign repel, while charges of opposite sign attract, and
  • the effect of charge between two charged bodies falls off with the square of the distance, and
  • the effect of charge can be superimposed, and
  • oppositely charged classical bodies absolutely will "slam together."

First order: lumped elements

An component is any discrete unit in a circuit that is doing more than linking multiple components. Elements which link components are wires, and are usually reasonably conductive (otherwise they wouldn't be very good links).

The "lumped element model" concentrates components to single points, and assumes ideal (simple) behavior. This induces a graph of finitely many planes, and allows us to work with ODEs rather than PDEs. It's more useful IMHO to relax the concentration, and treat components as ordered cycles corresponding to their geometry. In this model, when wires intersect, they become a single wire. A wire is a node, and each pin is a node.