microtexan said:
Why are you trying to make a better equation for flux density?
I thought it would be easier to design a saturating switching power supply transformer with a different equation for B.
The existing B=V*10^8/(4.44*A*N*f) uses AC voltage and frequency. I think current is more suitable.
So I've come up with some new ones:
B=0.1415*Al*N*I/A
B is in Gauss
Al is the core's inductance in milliHenries at 1000 turns.
N is the number of turns that pass through the core.
A is the core's cross sectional area in cm^2.
I've also come up with:
Al=:mu: *0.89*A/Le
:mu: = the core material permeability.
A is the core's cross sectional area in cm^2.
Le is the core's magnetic path length in cm.
This way you can easily see that the Al value is dependent only on core material and core geometry.
You see I had some trouble verifying the published specifications of an Amidon toroidal core FT240-77 made of type 77 material that has a characteristic permeability of 2000. The specs in Amidon's leaflet said it had an Al value of 3130. Their catalog said it was about 2750. My own test with an oscillator to determine inductance found the real thing to be closer to 1690.
I can elaborate on the derivation of the formulas but only if you're interested.