These do not change when you switch supplier or platform. Ohm's law behaves the same in an Arduino project and in a power station. Read Fundamentals first; every other page assumes it.
Charge, voltage, current, resistance, power. Ohm's law, prefixes, series and parallel, Kirchhoff, ground, DC vs AC, and the safety line.
Current limiting, voltage dividers, pull-ups. Colour codes, E12 values, tolerance and power rating — with a divider calculator.
One-way valves, forward voltage, rectification, flyback protection. Includes the LED resistor calculation you will do constantly.
Storing charge, decoupling, smoothing, RC time constants. Types, polarity, voltage derating — with an RC calculator.
BJTs and MOSFETs as switches and amplifiers. Base resistor sizing, saturation, logic-level gates, driving real loads.
Magnetic storage, reactance, impedance, RC and LC filters, resonance, transformers. Why AC needs different thinking.
Linear vs switching regulation, efficiency and heat, batteries and chemistry, brownouts, protection and decoupling strategy.
Logic levels, GPIO limits, pull-ups, ADC, PWM, and the three buses you will meet: UART, I²C and SPI. Where hardware meets code.
Practical skill, tools and judgement. Most of this is readable before you own anything — which is the point, since it tells you what to buy and stops the first evening being a wasted one.
Symbols, designators, layout grammar, breadboard anatomy, and which four sections of a datasheet actually matter.
Multimeter technique for voltage, current, resistance and continuity. What a scope adds, and a systematic method for finding faults.
Wetting, flux and intermetallic bonds. Technique, temperatures, joint faults, desoldering, tip care, through-hole vs SMD.
The mistakes everyone makes once, and an ordered method that beats swapping parts: supply, ground, node voltages, then components.
What to buy and where the money should go, what to skip, and eight projects in order — each teaching the next one's prerequisite.
Checkpoints and drill answers are stored in this browser and restored when you reopen a page. Export writes a JSON file you can keep beside the folder or move to another machine.
Every page uses the same tiers, so you always know how deep you are.
| Tier | Question it answers | You leave able to… |
|---|---|---|
| 0 · Ground | What is this and why does it exist? | Explain it in one sentence |
| 1 · Mechanics | How does it actually behave? | Predict what a circuit will do |
| 2 · Choose | What value or part do I pick? | Do the sizing calculation yourself |
| 3 · Build | How do I use it in a real circuit? | Wire it correctly first time |
| 4 · Fail | How does it break, and what does that look like? | Diagnose instead of guess |