I'd guess you are providing an open (magnetic) circuit.I'll try this with three nails in contact, and let you know.Brian W
On Tuesday, May 4, 2021, 05:36:52 PM CDT, Carl Mungan via Phys-l <email@example.com> wrote:
I’m wondering about the following. Some multimeters can measure inductance. I have tried with a few coils lying around and I find that with nothing (ie. air) in the core, I get one value of the inductance, say maybe 0.1 H for things like Pasco coils or even some larger coils. If I now insert iron rods or laminated iron bars into them, the inductance increases by about a factor of 10, maybe a bit more or maybe a bit less.
My question is: Since the relative permeability of iron (even at low applied fields) can easily be 10 000 or more, why am I not seeing substantially bigger increases in the inductance when I insert these iron cores?