Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Magnetizing inductance (µH)

Magnetizing (primary) inductance of the transformer.

Coupling coefficient

Coupling coefficient strictly between zero and one; unity coupling implies zero leakage.

Estimate leakage inductance from the magnetizing inductance and the winding coupling coefficient. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Leakage inductance (µH)

Estimated leakage inductance seen at the primary.

• Transformer ratios and losses depend on waveform, frequency, core material and flux, turns, winding resistance, leakage, magnetizing current, load power factor, temperature, insulation, and construction. Ideal turns-ratio equations do not establish regulation or thermal rating.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• Transformer Magnetizing Current

  Estimate sinusoidal RMS magnetizing current as V/(2πfLm) for a linear magnetizing inductance. Core saturation, hysteresis, and winding resistance are excluded.

• Magnetic Air Gap Length

  Solve a simple magnetic-circuit inductance model for required air-gap length: lg=μ₀N²A/L−lc/μr. This treats fringing and leakage as negligible; a negative result means the requested inductance needs no positive gap under the model.

• Common-Mode Choke Impedance

  Estimate one winding's series RL impedance magnitude at frequency f as √[R²+(2πfL)²]. Enter the effective common-mode inductance and resistance at the operating point; real choke impedance also includes core loss, capacitance, and self-resonance.