Safety boundary
Use only low-voltage classroom batteries/components under supervision or an approved circuit simulation. Never use mains voltage.
Explicit physics instruction
Circuit reasoning should begin with topology: identify nodes, branches, and series/parallel relationships before calculating.
Then apply V=IR and power/energy relations with units and a direction/magnitude check.
Engineering choices require constraints such as voltage limits, component power ratings, and desired brightness/current.
Core relation/model: V=IR; P=VI; E=Pt
Worked example
A design that doubles current through the same resistor quadruples I²R heating, so thermal constraints can dominate.
Guided question
Why can a lower equivalent resistance increase source current and power demand?
Independent work
- Solve one mixed-network problem.
- Calculate component power.
- Write a design tradeoff involving current, power, and resistance.
- Record one correction.
Spiral retrieval bridge
- From Week 29: distinguish electric field from electric potential.
- From Week 13: connect power with energy transfer rate.
- From Week 07: use a system diagram before writing equations.
Misconception check
A circuit that 'works' mathematically may still violate component or safety constraints.
Formative check
Why should power ratings be checked after current/voltage calculations?
Reveal response
Because excessive power can overheat or damage components.
Mentor evidence conference
Ask Archaemenes to audit units, assumptions, model selection, and whether the evidence supports the conclusion.
Teacher guidance
Foundation: Use a circuit-analysis checklist.
Core: Integrate topology, Ohm's law, and power.
Extended: Optimize a low-voltage design under constraints.