CALCULATORS / MAGNETICS AND INDUCTIVE DEVICES

Inductance from magnetic geometry calculator

Linear magnetic circuit from supplied permeance; no saturation.

magnetics-inductance.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	inductancemH
	10
	6.4

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

inductance target10.00 mH✓ passes

BASELINE INPUTS

turns100 permeance0.000001 H

CALCULATED

inductance10 mH

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Inductance from magnetic geometry
# Scope: Linear magnetic circuit from supplied permeance; no saturation.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

turns = 100
permeance = 0.000001 H

inductance := turns^2*permeance [mH]

check inductance target: inductance >= 5 mH

scenario alternative: turns = 80

Calculated from your source · not saved

Baseline · Baseline

inductance target10.00 mH ✓ passes

alternative · alternative

inductance target6.40 mH ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

inductance: inductance = turns^2*permeance [mH]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

turns: 100
permeance: 0.000001 H

Calculated

inductance: 10 mH

Assumptions and limits

Linear magnetic circuit from supplied permeance; no saturation.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Inductance from magnetic geometry. Inputs: turns; magnetic path; gap; material. Outputs: inductance estimate; saturation screening. Model scope: Magnetic-circuit approximations with calibrated material data. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: turns, magnetic path, gap, material
Outputs: inductance estimate, saturation screening
Modes: calculate, compare, sweep
Drawing: Magnetic circuit and flux plot

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS