Fundamentals#

Nature’s rules and universal constraints — the physics layer that everything else is built on. Ohm’s law, Kirchhoff’s laws, power and energy, passive component behavior, circuit analysis techniques, and the unit system that ties it all together.

All of it seems simple until it needs to be applied to a real circuit on the bench. Analog and digital design are human-engineered behavior layered on top of these rules. When something doesn’t add up, the answer is almost always here.

Sections#

• Laws & First Principles — The non-negotiable rules: Ohm’s law, Kirchhoff’s laws, power, conservation of energy, and energy storage dynamics.

• Thermal Reality — Dissipation ratings, derating, thermal resistance chains, and why quiet thermal failures happen before spectacular ones.

• Signaling Models — What is the signal and what is it measured against? Go & return paths, reference planes, single-ended vs differential, balanced vs unbalanced, and common-mode rejection.

• Circuit Analysis Techniques — Series/parallel, voltage dividers, node/loop analysis, and Thevenin/Norton equivalents.

• Passive Components — Resistors, capacitors, inductors, and transformers beyond the ideal models.

• AC & Impedance — Frequency-dependent behavior, reactance, complex impedance, and resonance — the bridge from DC analysis to AC reality.

• Magnetics in Practice — Inductors and transformers beyond the ideal: saturation, losses, parasitics, noise, inrush, and what to look for on the bench.

• Electromechanical Devices — Components where electrical signals create physical motion or sound: relays, reed switches, contactors, speakers, and buzzers.

• Semiconductors — Diodes, BJTs, MOSFETs, and thyristors: the behavioral primitives that make active circuits possible.

• Units, Notation & Measurement — SI prefixes, schematic conventions, and what instruments actually report.