Physics
Transformer
Two coils and a closed iron core: the flux those arrows carry is the only thing linking them. Trade turns for voltage; open the load and the primary shrinks to the magnetizing trickle.
What happens
The model is the magnetic circuit itself: flux from the magnetic Ohm's law, two coupled loops, one ODE integrated live - no phasors are stored, yet the steady state lands on the phasor answer to five digits (the twin checked). The turns ratio is readable from the winding stacks, and its sag below N2/N1 is the winding resistances' honest bite. Saturation and leakage are deliberately absent; the linear circuit already carries the whole story.
Equations used in the module
Equations V₂ / V₁ = N₂ / N₁, I₂ / I₁ = N₁ / N₂ ε = −N dΦ/dt Φ = B A, B = μ₀ μ_r N₁ I₁ / l power: P₁ = ⟨v₁i₁⟩, P₂ = ⟨v₂i₂⟩ over a cycle; P₁ − P₂ = ⟨i₁²⟩R₁ + ⟨i₂²⟩R₂ (copper); η = P₂/P₁; ideal secondary RMS: V₀/√2 · N₂/N₁
