This simulator wires two physical resistor modules — R1 and R2 — to a current-limited bench supply, in series or in parallel, and solves Ohm's law and Kirchhoff's laws for every branch in real time. Adjust supply voltage, resistance values, topology, supply current limit and resistor power ratings, or inject an open-feed or shorted-output wiring fault, and watch voltage drops, branch currents and resistor body temperatures respond live.
• A real-time 3D cutaway workbench with a current-limited bench supply, an R1 axial resistor module, an R2 wirewound power resistor, an animated series/parallel patch matrix, a series ammeter, a voltmeter across R1, and contact temperature probes — with home view, focus-selected-part, toggleable full enclosure, exploded view, auto-rotate, expand and show/hide-labels controls, tappable numbered components with callouts matching the companion diagram. • Seven live controls: supply voltage demand (0–24 V), resistor R1 (10–1000 Ω), resistor R2 (10–1000 Ω), a series/parallel connection selector, supply current limit (0.02–1 A), each resistor's power rating (0.25–5 W), and a wiring-condition selector (healthy / open positive feed / shorted output through a 0.05 Ω lead path). • Play/pause, single-step (0.1 s) and larger-step (1 s) time controls, plus a playback-speed selector (10x slow motion, real time, 10x faster, 1 minute per second). • Reset laboratory action, with a live sequence narrative, operating-point summary and switch-state tokens. • Twelve live metrics: actual source terminal voltage, total source current, healthy-network equivalent resistance, R1 and R2 voltage drops, R1 and R2 branch currents, R1 and R2 dissipation, R1 and R2 estimated body temperature, and output/short-path dissipation. • A Curves & measurements tab with circuit-measurement and response/stored-state charts (voltage drops, source voltage, and both resistor body temperatures), the full series/parallel/thermal equation model, and snapshot measurements. • An Experiments tab with four guided scenarios (series voltage division, parallel current division, current limiting, output short), a model-verification bench of independent automated checks, and a timestamped event log with a copyable trial report. • A Learn & assess tab with guided lessons (apply Ohm's law locally, connect the network, respect the source limit, convert electrical power to heat), a knowledge-check quiz and a written scope/reference statement.
In series, R1 and R2 share one current path, so the same current flows through both while voltage divides between them in proportion to resistance. In parallel, both resistors instead see the same voltage while their branch currents divide inversely with resistance — the simulator switches the modeled network topology live through an animated patch matrix rather than just relabeling numbers.
The bench supply is current-limited, not voltage-unlimited: actual source current is I = min(Vset/Req, Ilimit), and once the demanded current would exceed the limit, the supply reduces its own output voltage to hold current at the limit rather than forcing the requested voltage through a low-resistance load. This is exactly the behavior demonstrated in the Current Limiting and Output Short experiments.
Each resistor's dissipation, Pk = VkIk = Ik²Rk, drives a first-order thermal model — 3 dT/dt = P − (T − 25°C)/60 — so body temperature approaches equilibrium gradually rather than jumping instantly, using a fixed 60 K/W thermal resistance and 3 J/K heat capacity for both teaching modules. An open positive feed drives current to zero; a shorted output collapses the load to a modeled 0.05 Ω lead path that bypasses the resistor network entirely, which the supply's current limit then constrains.
The model is explicitly scoped to linear resistors, ideal meters and a static regulated-source envelope: there is no resistor temperature coefficient, no fuse or physical burn-out behavior, and no parasitic wiring inductance. Component changes are treated as fresh design experiments at the retained state, not live component swaps on an energized circuit.
In series, R1 and R2 carry the same current while their individual voltage drops differ according to their resistance values. In parallel, R1 and R2 share the same voltage while their individual branch currents differ according to their resistance values. Neither topology makes voltage or current equal for resistors of different values on the "other" quantity.
The bench supply is current-limited: actual output current is I = min(Vset/Req, Ilimit). When a low network resistance would otherwise demand more current than the configured limit, the supply automatically reduces its output voltage to hold current at the limit rather than violating it — this is normal current-limited regulation, not a failure of Ohm's law.
Each resistor's instantaneous power, Pk = Vk·Ik = Ik²·Rk, drives a thermal equation (3 dT/dt = P − (T − 25°C)/60) with a fixed 60 K/W thermal resistance and 3 J/K heat capacity, so body temperature rises gradually toward an equilibrium set by dissipation and ambient heat loss rather than changing instantaneously or altering the resistor's resistance value.
An open positive feed removes the current path entirely, so current falls to zero. A shorted output instead replaces the resistor network with a modeled 0.05 Ω lead path, which the current-limited supply then holds near its configured limit — in the built-in Output Short experiment this produces only about 10 mV across the short path at the 200 mA default limit.