Components

The parts, what they do, and how to choose them.

ResistorsTypes, ratings, tolerance and the colour code.CapacitorsCeramic, electrolytic, film and variable: choosing the right one.Inductors, toroids and ferritesCores, permeability, and why ferrite beads matter.Crystals and resonatorsPiezoelectric frequency references and filters.Switches, relays and fusesControlling and protecting circuits.BatteriesChemistries, capacity, internal resistance and charging.Wire, cable and gaugeAWG, current ratings, and where each wire type belongs.