I am calculating AC flux density again. (I do this every few years.)
I recall some formulas use 4.0 in the denominator and others use 4.44. I think it has to do with waveshape but my dementia seems to be taking over.
thanks, Bob N9NEO
simple transformer Q
Aug 19, 2018
3 Replies
3 rd hit on google:
formatting link
Page 6
Difference is wave shape as you wrote
Cheers
Klaus
SI units:
N = Vrms / (4 Bmax Ae F)
Vrms == Vpeak for a square wave.
For sine, use Vrms and use 4.44 coefficient (actually pi*sqrt(2)).
If you carry a m / u / M through, you get units handy for SMPS work: N (turns) == (V) / ( (uV.s / (mm)^2) (mm^2) (MHz) )
Datasheets sometimes give Ae in cm^2, just mentally shift the decimal over.
Or type it in, with all units, and let Google Calculator figure it out. No one actually needs to know unit conversions anymore. (Downside: Google doesn't understand cgs units (Oersted, Gauss..).)
Tim
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/
"Yzordderrex" wrote in message
news:cf54cb4a-0ca9-4b98-980d-703d5586b824@googlegroups.com...
>I am calculating AC flux density again. (I do this every few years.)
>
> I recall some formulas use 4.0 in the denominator and others use 4.44. I
> think it has to do with waveshape but my dementia seems to be taking over.
>
> thanks,
> Bob
> N9NEO
Thank you.
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