FOR TEACHERS
A working electronics lab in the browser: free, no sign-up, nothing to install and nothing to buy. Every pupil’s circuit runs on the same solver the rest of the site does, so wrong wiring behaves like wrong wiring. Any browser works, a Chromebook included, with no account and no server in the loop except the shop teacher’s chat, which the site works fine without.
What it needs
Any browser on any machine, a Chromebook included. Sound helps, but every lesson can be read instead of heard. No account, ever. The only part of the site that talks to a server is the shop teacher’s chat, and the bench, the Ladder and the classroom all work without it.
The course as a class
The twelve lessons, in order: what each one teaches, the film’s running time, the bench build it sends the class to, and the minutes the classroom already budgets for the lesson and that build together.
| Lesson | What it teaches | Film | Bench build | Lesson + build |
|---|---|---|---|---|
| What electricity is | Voltage is the push (energy per charge, measured in volts); current is the flow of charge (measured in amps). Charge does not leave a cut wire the way water leaves a cut pipe; the wire is already full of charge and the whole column moves together. | 2:47 | Light the LED | 6 min |
| The loop | Current needs a closed loop from + through the parts back to −; a switch is a gap in the loop; switches in series both need to close (AND) while switches in parallel need only one (OR). | 2:01 | Two switches in series | 6 min |
| Resistance and Ohm's law | Ohm's law: I = V / R (volts divided by ohms gives amps). A resistor's colour bands give its value; its power rating in watts is the heat it can shed, and P = V × I above that rating burns it. | 2:43 | Ohm's law, by eye | 10 min |
| Series and parallel | In series the same current flows through each part and voltages add (resistances add). In parallel each part sees the same voltage and currents add (combined resistance drops). Batteries in series add volts; capacitors in parallel add farads. | 2:19 | Parallel LEDs | 8 min |
| Capacitors and time | A capacitor stores charge (farads = charge per volt). Charging through a resistor takes time set by R × C, about 63% per time constant. Capacitors pass changes and block steady current; electrolytics have polarity. | 2:34 | Capacitor battery | 8 min |
| Diodes and LEDs | A diode conducts one way only and takes a fixed forward voltage (about 1.9 V for a red LED) rather than a proportional share; an LED needs a series resistor to set its current, and reversed it stays dark but undamaged. | 2:17 | Series LEDs | 7 min |
| Transistors as switches and amplifiers | An NPN transistor lets a small base current control a collector current about beta (around 100) times larger; with the base fully on or off it is a switch, and in between it is an amplifier where the output follows the input. | 2:25 | Tiny current, big current | 10 min |
| Oscillators | The two-transistor astable multivibrator flips because each transistor turns the other off through a capacitor that recharges through a resistor; period ≈ 1.4 × R × C, so smaller C or R means a faster flip (a flasher at 100 µF, a 700 Hz tone at 0.1 µF). | 2:38 | Two-transistor flasher | 8 min |
| Sensors | A sensor turns a physical quantity into resistance (photocell: about 1 kΩ bright, hundreds of kΩ dark). In a voltage divider the sensor's share of the volts changes with it, and a transistor at the midpoint turns that into a switch or a control. | 2:25 | Night light | 7 min |
| Reading schematics | A schematic shows connections, not positions: the same schematic wires many ways. Symbols carry meaning (curved capacitor plate is the electrolytic's −, LED triangle points the way current flows, NPN arrow points out of the emitter), and reading starts at the battery + and follows the loop. | 2:18 | Make a tone | 7 min |
| Measuring | A voltmeter goes across a part (parallel, very high resistance); an ammeter goes in the loop (series, very low resistance) and must never be clipped across a part. Voltages around a loop add to the source voltage; currents into a junction equal currents out. | 2:10 | Voltage divider | 7 min |
| Safety and real parts | Danger is set by current through the body, not volts alone: 9 V through skin is under a tenth of a milliamp and safe, mains at 120–240 V can push tens of milliamps across the chest and is not. Heat, polarity (electrolytics, LEDs, battery), and part tolerance are the real-world details the simulator only hints at. | 2:41 | Smoke test | 6 min |
Enough to plan a single period or a whole term: the film times and the lesson minutes are the classroom’s own numbers, so this table can’t drift from the videos or the twelve lessons behind them.
Three ways to run it
A single period. One lesson, one bench build, one question the shop teacher can grade. Pick a row from the table above, open its build on the bench, and let the room wire it.
A unit. A level of five experiments and the three sign-offs that open the next one — five periods, roughly, with the Ladder keeping score.
A club or after-school. The missions, the Kids Zone for a younger room, and free play on the bench, with nothing that has to be finished by a bell.
Assessment that already exists
A build is checked by the grader against live evidence — the readings the simulator actually took, not a guess. A pupil earns a sign-off by explaining their build, in their own words, to the shop teacher. Both marks are visible on the Ladder, and both mean exactly what they say: formative, not a mark, and nothing is stored about a child beyond their own device unless they choose a player code.
A pupil, or a whole room, can print or download that record: the Ladder’s progress sheet, one page, the words “passed” and “explained it” and nothing that looks like a grade.
Print and hand out
The Manual Library has every level, mission and the whole classroom as booklets: PDFs you can print, each build’s parts and wiring on its own sheet, and a schematic beside every one of them.
Safety and the real thing
The simulator is where mistakes are free. The last lesson, Safety and real parts, is about the parts that are not: mains, and what a pupil should never try outside a simulator.
Privacy, in a teacher’s terms
No accounts required, no personal data asked for. Progress lives on the device it was earned on; a player code only exists if a pupil wants their work on a second machine, and they type it in themselves. For a younger room, the Kids Zone’s grown-ups page covers the same ground in a parent’s terms.