if you prefer to hear more university-like professor presentation about magnetism see the following sets of video
What is Magnetic Flux?
In this video we will explain what is magnetic flux in the magnetic coupling circuit.
5 min
Inductor Saturation and its Consequences Explained
prof. Sam Ben-Yaakov explains behaviour of inductor in saturation state and its consequences.
10 min
What is Self Induction ?
What is self induction with alternating voltage source in the magnetic coupling circuit ?
4 min
Switching Frequency Impact to Ferrite Cores Losses
prof. Sam Ben-Yaakov explains the effect of switching frequency on ferrite cores losses and importance of f*Bpk
16 min
Polarity Convention
lets explain the polarity of the induced voltage.
3 min