#solenoid

Inductor-design electromagnetics as an API, computed locally and deterministically. The solenoid endpoint computes the inductance of a straight coil with the long-solenoid formula L = μ₀·μr·N²·A/l, from the number of turns, the coil length, the cross-sectional area (or diameter) and the relative permeability of the core — a ferromagnetic core multiplies the inductance. The toroid endpoint computes the inductance of a doughnut-shaped coil of rectangular cross-section, L = μ₀·μr·N²·h·ln(b/a)/(2π), from the turns, the axial height and the inner and outer radii; the toroidal shape confines the magnetic flux so there is little stray field. The energy endpoint computes the magnetic energy stored in an inductor, E = ½·L·I², and the flux linkage Φ = L·I, from the inductance and current — the energy released when the current is interrupted causes the inductive kick. Lengths are in metres, area in square metres, inductance in henries (millihenries and microhenries also returned) and current in amps, with μ₀ = 4π×10⁻⁷ H/m. Everything is computed locally and deterministically, so it is instant and private. Ideal for electronics, RF, power-supply, filter and motor-design app developers, coil-winding and inductor-sizing tools, and electromagnetics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is inductance from geometry; for the resonant frequency and reactance use a resonance API and for full AC impedance an impedance API.

api.oanor.com/inductance-api

Magnetic fields and forces as an API, computed locally and deterministically. The wire endpoint computes the magnetic field around a long straight current-carrying wire, B = μ0·I/(2π·r) — the field at a distance r from a wire carrying a current I — and solves for whichever of the current, the distance or the field you leave out, reporting the field in tesla, millitesla, microtesla and gauss. The solenoid endpoint gives the uniform field inside a long solenoid, B = μ0·n·I (n turns per metre, given directly or as a total number of turns over a length), or the field at the centre of a circular loop, B = μ0·N·I/(2R). The force endpoint computes the magnetic force on a moving charge, F = q·v·B·sin(θ) (the Lorentz force), or on a current-carrying wire in a field, F = B·I·L·sin(θ), with the force per metre. The vacuum permeability μ0 = 4π×10⁻⁷ is built in, with an optional relative permeability for a magnetic core. Everything is computed locally and deterministically, so it is instant and private. Ideal for electromagnetism-education tools, electromagnet, motor and inductor design, magnetic-sensor and physics-simulation apps. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is magnetostatics; for Coulomb electrostatics use a Coulomb API and for Ohm's-law circuits use an Ohm's-law API.

api.oanor.com/magnetic-api