This is a toroid flux density (B) calculator that helps with the selection
of a suitable toroid used in RF applications. For both ferrite and iron
powder toroids, Amidon
recomends not to exceed the values in the following table. Small
variations of these values may exist for the various materials available.
Note: The value of such calculation using Amidon's method is questionable
when one takes into account
the specific properties of the materials used (relative permeability) at the frequency
of interest, as reported in VK2OMD's
In this article, an example is given for two same physical dimension toroids, one
made with -61 material and one with -43. It is shown that the -43 material would result in
too much heat being dissipated in the ferrite while the -61 would be fine, if operated
at the 'safe' voltage indicated by Amidon's calculation...
The formula suggested by Amidon is the following:
The crossections Ae in square centimetres of some popular toroid dimensions are:
Enter E in volts RMS:
Enter Ae in square centimetres
Enter number of turns N:
Enter frequency in MHz:
The calculated flux density Bmax in gauss is:
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