I have a 15µH 1.6A inductor, this one.

The operating current is 1.3A, but the saturation current is 1.6A.

  1. What is the difference between these?
  2. Will the inductor work properly at less than 1.3A or less than 1.6A?

What they're telling you with the saturation current is that above 1.6A, the core can't take any more magnetic flux, and this translates into a change in the effective inductance when the current gets into that realm. You can put more current through the winding, and you do get more flux as a result, but the effective permeability of the core drops off.

The effect won't be a sharp break, either; you would start to see some of the effects as you get near the saturation point. If you apply a pure sine wave voltage across the coil that would result in less than 1.3A peaks, the current will also be sinusoidal, but if you run the voltage up to where the peak currents would reach saturation, the current waveform will have a significant harmonic component.

  • 3
    \$\begingroup\$ To add, the operating current usually doesn't have anything to do with it being an inductor per-se, but simply the maximum current you can shove through it within the rated temperature range. And finally, unless you're relying on some of the non-ideal effects of inductors (namely resistance), you can freely use ones with higher current ratings. \$\endgroup\$ – Nick T Nov 12 '10 at 4:03

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