where N is its number of turns in the toroid, R1 and R2 are the inner and outer radii of the toroid, h is the height of the toroid, and \(\displaystyle μ_0=4π×10^...where N is its number of turns in the toroid, R1 and R2 are the inner and outer radii of the toroid, h is the height of the toroid, and μ0=4π×10−7T⋅m/A is the permeability of free space. In the first time constant τ, the current rises from zero to 0.632I0, and to 0.632 of the remainder in every subsequent time interval τ.
