In the experiment I need to

**minimize the current needed to saturate soft ferrite**.

So I am looking for inexpensive methods to measure saturation. I am passing current through a coil around the soft ferrite.

Intuition tells me that shape and volume are factors.

I also note that a ferrite toroid is a closed magnetic circuit (no air gap) and that a rod is not a closed magnetic circuit.

Thank you for weighing in on this subject.