The Playbook
Learn electronics, one page at a time
A game in your notebook: each page asks about a real circuit, solved live as you answer, from Ohm's law to control loops.
Open the Playbook Opens in the app on 1 December, with Circuit Notebook 1.0
Eight chapters are free. Nothing to install; it works on a phone.
- 33 mA
- 20 mA
- 13 mA
Fourteen chapters, in order
Each page unlocks the next. A chapter ends with a review, six questions drawn from all its pages.
Free, for everyone
- Start here How the Playbook works, the symbols, the prefixes.
- Ohm's law V = I × R, the power it costs, and the colour code.
- Series & parallel How resistors add up, and how current shares.
- Voltage dividers Two resistors share a voltage.
- Fix it Debug like a technician: click what is wrong.
- Diodes & LEDs One-way valves and the resistor that goes with them.
- Capacitors & RC A tank for charge: how fast it fills.
- Signals & filters Sine waves, the RC filter, decibels.
With Premium
- Transistors A switch you drive with a current.
- Op-amps Amplify, compare, follow.
- Logic gates AND, OR, NOT and the truth table.
- Magnetics & inductors The coil, the flyback diode, transformers.
- Power supplies From the mains to a clean rail.
- Control systems Measure, compare, correct: the loop.
Beside the path
Labs
Ten workbenches with knobs and meters: turn a value, the circuit answers. Free: the Ohm's law, divider and LED labs.
Reference sheets
Fourteen sheets: the formulas, the usual mistakes, a page to practise. Free: Ohm's law & power, the voltage divider, the resistor.
Badges
Badges to collect, from bronze to legendary, earned in the game and in the editor. The sparks you win dress your notebook: papers, pens, stamps.
Free: 8 chapters, 3 labs, 3 sheets, the speed rounds and the page of the day, 3 pages a day.
Premium: all 14 chapters, every lab and sheet, as many pages as you like. See the plans