Two ideal ohmic loads, an ideal voltage source, ideal wires and a master switch. No shorts, AC, capacitors, internal resistance or thermal feedback.
The flashlight view appears only for the single-load circuit; series and parallel arrangements are separate circuit comparisons.
Current markers are explanatory and slowed down. Their spacing and speed are not electron trajectories, charge density or signal propagation.
Lamp glow is a qualitative indication of load power. Home observation uses an intact flashlight, not a wiring or battery-building procedure.
Ohm’s law, with a scope: For these ideal fixed resistors, I = V/R. Series: Rₑ = R₁ + R₂. Parallel: 1/Rₑ = 1/R₁ + 1/R₂. An open switch gives I = 0. We omit switching transients and use the settled DC state.
An accounting check: P = VI = I²R. In series, V₁ + V₂ = Vsource. At a parallel junction, I₁ + I₂ = Isource. Adding the load powers gives the source power. That is an energy balance, not a calibrated brightness scale.
Why real lamps differ: A filament heats up and changes resistance, so doubling voltage need not double its current. The battery also has internal resistance. The virtual source stays at its selected voltage; the glow shows relative modeled power, not lumens or temperature.
What has been checked
Analytical reference cases, conservation or transition invariants, finite drawing commands, bounded setup parsing, discovery and route integrity are checked automatically. These checks do not establish anatomical fidelity, learner outcomes or browser/device compatibility. Independent subject review, learner trials, comprehensive accessibility review and browser video encoding checks remain pending.
Each source supports the associated claim. Sources do not certify this implementation or its visuals.