What this series is
A complete walk through electrical theory and the wiring code that governs it, from charge and current up to power systems and the rules for installing it safely in a building. It assumes nothing and skips nothing, and the order is built so each idea rests on the one before it. It is written for electricians, but anyone curious about how electricity actually works should be able to follow along.
What sets it apart from a textbook is that you can play with it. Most pages carry a small interactive: change a value and the graph answers back. Raise the frequency and the phasors spin faster; drop the load and the voltage sags. Electricity is hard to picture from equations alone and far easier to grasp once you can watch it respond.
Theory is universal, the rules are local
The physics does not change from one country to the next. Ohm's law, Kirchhoff's laws, and Maxwell's equations hold the same in Lisbon, London, or Los Angeles, so the theory here is written in SI units throughout.
The regulations are another matter. What may actually be installed, how it is earthed, which protective devices are required, the minimum conductor sizes: all of that is decided jurisdiction by jurisdiction. This series follows the European framework, the harmonised IEC and CENELEC standards of the HD 60364 family, and within it Portugal's RTIEBT (Regras Técnicas das Instalações Elétricas de Baixa Tensão, Portaria n.º 949-A/2006). The formulas come from the classic textbooks and travel anywhere; the rules come from the RTIEBT and apply where that code does.
How the course is put together
The topics are resequenced so each one builds on the last, rather than following the order they were originally filed in. Every page is laid out the same way, in five steps:
- Concept. A short piece of prose that lays out the theory.
- Interactive. The graph you drive to build the intuition.
- Worked example. Real numbers, step by step.
- Sources. Citations: the classic textbooks for theory, Portuguese law for the regulations.
- Quick check. Two or three questions to test yourself.
The material runs across eight areas, from the bare fundamentals through to maintenance:
| Area | Covers |
|---|---|
| Fundamentals | DC, DC analysis, magnetism and electromagnetism, AC, three phase |
| Electronics | semiconductors, BJTs, power devices, digital logic |
| Machines | electric machines and transformers |
| Protection and regulation | protection, safety, materials, measurement; the regulatory core, RTIEBT |
| Installations | residential to industrial, lighting, CAD |
| Power systems | generation, transmission and distribution, substations |
| Automation | automation and control, where programming bridges in |
| Maintenance | maintenance and organisation |
The regulatory areas, protection through power systems, follow the RTIEBT within the European HD 60364 framework. We start with the next part, Direct current: charge, current, voltage and resistance, Ohm's law, power and energy, series and parallel, and sources.