FERRETGame engine over Babylon.js
Ferret

Electric circuits

Skill ferret-physics-electric · download all skills · SKILL.md

When to use#

Lamps that surge and burn, fuses and breakers that trip, motors and generators, wiring puzzles.

The model#

A Circuit solves its elements each step (nodes by name, '0' is ground). Parts: VSource, ISource, Battery, Resistor, Lamp (inrush, burnout, T), Heater, Wire (overheat), Fuse (I²t), Breaker (thermal + magnetic), Rcd, Switch, Capacitor, Inductor, Diode, IdealTransformer, DCMachine, InductionMotor, Relay. circuit.phasor(ω) solves in the frequency domain.

Steps#

  1. c.add(new VSource('V', 'a', '0', 230)) and the loads; every node needs a path to ground.
  2. c.step(dt); sub-step fast circuits with maxStep; call circuit.restart() after throwing a switch.
  3. Events: circuit:short, circuit:blown, lamp:burnt, trip, overheat.
  4. Motors: copy the shaft's omega to the machine, feed its torque to the shaft (ferret-physics-mechanisms).
  5. Link faults to the world: wireFire, arcFlash (ferret-physics-links).
  6. Commands: circuit.add|connect|set|state|step, meter.read.

Check afterwards#

A 2.3 kW kettle on 230 V draws 10 A; kettle plus dryer trips a 16 A breaker; rectifier ripple is about I / (2 f C).

What usually goes wrong#

  • NaN or huge voltages: a node with no path to ground, or a source across a short.
  • A switch makes a spike: no restart().
  • A motor does not turn: omega not copied, or k sign reversed.
  • Energy does not close on a resonating circuit: lower maxStep.

Files#

  • reference/electric.md — Circuits with batteries, lamps, motors, generators and heaters; fuses, breakers and wires that fail; mains and three-phase.
  • reference/api-physics-electric.md — every export of @ferret/physics-electric with signature and doc comment
  • reference/commands.md — 7 commands of these packages with their arguments
  • recipes/machines-and-circuits.md — Six recipes: a lamp that surges and burns, a rectifier that smooths, a transformer, a wind turbine lighting a lamp through a generator, a winch that cannot run back, a flywheel that evens out a pulsing drive.
  • recipes/flooded-cellar.md — A burst main fills a cellar faster than the sump pump can empty it; the water reaches a socket, the circuit shorts, the breaker trips, the pump stops, and the flood wins.