# Magnetic fieldstrength, magnetic flux, magnetic flux density

1. Jun 11, 2010

### MikeHansen

I have a problem understanding magnetic fieldstrength, magnetic flux, magnetic flux density.

Some questions that answered may ease my understanding:

Is it true that the magnetic field strength B in the core caused by a current in a wire wound on a the same torodial magnetic core is proportional to the current I in that wire?

Is it also true that the current in this wire loop is caused by a voltage V applied to the ends of the wire? The current is resisted by the resistance of the wire right?

If the above is true, isn't it also true that the magnetic flux thru an area A in the toroid is related to the current thru the wire since flux is the integral of B dot dA?

The current is CAUSED BY the voltage so the voltage is related to the magnetic flux.

Please explain intuitively without too much math: WHAT IS MAGNETIC FLUX DENSITY??

In some litterature, like this Phillips Application Note: http://www.radio-kits.co.uk/radio-related/Linear_PA/ECO6907.pdf (page 4) it is stated that Bmax (max flux density) is related to Vmax (max voltage) and denominated by the area, the frequency of the applied VOLTAGE and the number of turns:

Bmax = Vmax / (2*pi*f * A * n)

In some litterature, it is suggested that the magnetic flux density is not related to the current but to the voltage. However, voltage causes current (movement of charged elements) that in turn causes the magnetic field. Isnt that true?

I would love an explaination that relates B, I, V, , flux flux density. I have seen many awkward papers and book chapters trying to explain basic magnetism but I have a feeling that the authors may not understand the topics properly. Could you refer my to a good website, good video, good book made by an authority on the field?

Mike Hansen