| the phase displacement between the fundamental components of the magnetic flux density and the magnetic field strength
NOTE 1 – Where a phase displacement can be associated with eddy currents, hysteresis or residual losses, the loss angle may be designated by δF for eddy current loss, δh for hysteresis loss and δr for residual loss.
NOTE 2 – The tangent of loss angle is often used to express the losses in a magnetic material:
where µ′ and µ″ are the real and imaginary components respectively of the complex permeability (symb.: µ).