I How does a ferromagnet increase the inductance of an inductor?

[Jaccobtw]

Inductance according to Faraday's law depends on a changing magnetic field. The magnitude of the induced emf depends on the magnitude of change in the magnetic field per change in time. Based on that, how does adding a constant magnetic field (a ferromagnet), increase the inductance of an inductor?

 

[.Scott]

The key is Magnetic Permeability. I always thought of it as adding a kind of fly wheel to the inductor - something to push against.

 

[DaveE]

Since this is the same question you asked in your other thread. I'll refer you to my same answer. Do you need us to elaborate?

OK I think I understand. The direction the inductor is wound will affect the direction of the magnetic field inside the inductor (or at least this is what I've concluded using the right hand rule), but it doesn't change the back emf.

So what about placing a magnet inside of the inductor? How does this increase inductance? If inductance depends on a changing magnetic field, how does placing a constant magnetic field inside an inductor increase inductance?

 

[DaveE]

The key is Magnetic Permeability. I always thought of it as adding a kind of fly wheel to the inductor - something to push against.

No, the OP isn't asking about permeability. He's asking about a DC bias flux added to the core and its effect on inductance.

PS: Note that this is based on "first order" effects, i.e. basic understanding. In fact a DC bias on cores does have, sometimes significant, effects because most core materials have a very non-linear B-H loop as used in real world applications.