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.

Inductance (H)

Circuit inductance.

Resistance (Ω)

Series resistance seen by the inductor.

Compute the RL circuit time constant tau = L / R; the current reaches about 63 percent of its final value after one tau and is effectively settled after five. 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]

Tau (s)

Time constant tau in seconds.

• Compact electronics formulas omit some combination of tolerances, temperature drift, bandwidth, loading, parasitics, noise spectrum, nonlinearity, clipping, calibration, layout, and device-specific limits. Typical datasheet values are not guaranteed limits.
• 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.

• RL Current Rise

  Compute the RL circuit current as it rises toward its steady-state value.

• Ripple Rating Check

  Compare the ripple current applied to a capacitor against its rated ripple current and report the signed margin percent; negative values mean the rating is exceeded.

• Saturation Margin

  Compare the peak operating current of an inductor against its saturation current and report the signed margin percent; negative values mean saturation is exceeded.