What this pilot teaches and records.

The pilot uses original examples to teach complete circuit paths, series and parallel behaviour, switch continuity, basic schematic symbols and a real-world safety boundary. It is an independent learning aid, not an approved City & Guilds product.

Relevant activities support learning towards selected foundations in Unit 202 learning outcome 4 and Unit 203 criteria 2.2–2.3. They do not establish that a criterion, unit or qualification has been achieved. The pilot does not cover the full syllabus, resistivity, full calculation proficiency or supervised practical competence, and it signs off no Unit 204 practical outcome.

The simulator uses a 12 V ideal source and fixed 12 Ω model lamps. Lamp state, current, voltage, power and feedback all come from this same constrained model.

• An open path has zero steady current; source voltage can still exist.
• Opening one parallel branch leaves the other complete. Opening the common feed interrupts both.
• Current is not consumed by a lamp. The load transfers electrical energy.
• Brightness is derived from model power. Floating-node voltages are not invented.
• The editor permits only supported single-load, series and parallel states; it does not permit a source short circuit.

A fixed resistor is a teaching approximation. A real filament lamp changes resistance as it heats, and an LED needs a different model. The displayed 12 V examples do not imply that every real battery or low-voltage system is harmless.

An unlit real lamp or an open control switch does not prove safe isolation. Archie should leave real wiring and equipment alone and obtain competent help. Nothing in the pilot is an instruction to wire a circuit, open equipment, take a mains measurement or use tools.

The safety questions check whether Archie keeps that boundary separate from the behaviour of a virtual circuit. A correct answer is learning evidence from this activity; it is not evidence of practical competence or permission to carry out electrical work.

Shared D1 record

When online, the browser sends the private pilot code in a request header and saves one validated, versioned progress record in Cloudflare D1. The code is not placed in the page URL. A parent browser connected with the same code can read the same record. Anyone with the code can access this pilot’s progress, so it should stay within the family; this is a small shared-access mechanism rather than a general account system.

Browser fallback and its limits

The active browser also stores the same progress snapshot locally before attempting the D1 save. Archie can therefore continue through a temporary network or API failure. That local copy belongs to one browser and device, can be lost when site data is cleared, and is not visible to the parent until it reaches D1. Revision checks prevent an older shared save from silently overwriting a newer record.

The access code is also kept in browser storage and a first-party cookie. The cookie lasts up to 30 days; clearing both copies means the code must be entered again. The D1 record has no self-service deletion control or automatic expiry in this pilot. An active-time field exists in the record, but the current learner interface does not populate it, so the parent view reports duration as not recorded.