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.

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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