magnetic flux, density and linkage?

Hi,

I'm having trouble distinguising/understand what exactly magnetic flux(0), magnetic flux density(B) and magnetic flux linkage are.

I know that magnetic flux is B x A, which seems to imply that it would be the total amount of magnetism or strength of magnetism over a given area. Would that be correct?

Also, to my knowledge magnetic flux density is a measure of the 'strength of a magnetic field'. If that's correct, then I can't seem to see how it differs from the magnetic flux (assuming my understanding of magnetic flux is OK :biggrin:

).

Lastly, I have no idea what magnetix flux linkage is :rolleyes:

All help appreciated :smile:

oh, and when you refer to just 'flux', is that the same as 'magnetic flux' (0)? So when you refer to a flux being produced, does that just mean that a magnetic field is produced?

Reply 1

dark_link

well you can kinda think of the magnetic flux as the total amount of magnetism due to some kind of magnetic field. think of a magnet as having a tank of magnetic power, this is the flux. (total number of field lines)

you can therefore think of magnetic flux density as the flux per unit area, which ties in with the idea of density. so it would be how intense the field is at a point, i.e. how much of the tank of flux is spread over that point. (concentration of field lines at a point)

flux linkage only applies when coils are involved. imagine a transformer - the primary coil generates a magnetic field with a strengh (flux density) of 5E-3 Telsa. if the secondary coil has 200 turns, over an area of 0.05m^2, then the flux that links each turn is: (5E-3)(200)(0.05), so you can see that if you take just the 5E-3 and the 0.05 m^2 that gives us the total flux in the area of the secondary coil. so you can think that all that flux (all those field lines) cut or 'link' each of the turns in the wire, so the total flux linkage is the total flux x the number of turns (which is 200).

i hope that answers you're question?

Reply 2

teachercol

A different picture/analogy that some find helpful:

Visualise a magnetic field as a like fluid flowing around a ciruit. The magnetic flux is the stuff that is flowing round. It can be denser in some places and thinner in others. The lines show the flow.

Currents are what make the magnetic flux go round.

I find this view of magentic fields much more helpful than 'lines of force' and 'magnetism' type ideas.