Three equivalent transformer models for your perusal.
http://www.ivesonaudio.pwp.blueyonde...lustration.GIF
Each is reduced to its simplest form for comparison
purposes, so all have constant mu, and no leakage or
capacitance.
The third, and much the simplest for visualising the view
from the primary side, is very useful for understanding the
lower frequency limit of an output transformer.
Note that for other winding ratios, the load resistance RL3
in the third model should be multiplied by the impedance
ratio, or the square of the voltage ratio, or the square of
the turns ratio.
Values of components shown are extreme for the purpose of
illustration. Input is 240Vrms 50Hz.
Graphs show currents on right axes and voltages on left.
Labels refer to probe names on respective circuit. Note
phase angle of magnetising current where it is shown on
first (AmpTurns/Turns) and third graph.
Last circuit and graph, bottom right, shows effect on
magnetising current of removing the load. With more
representative combinations of inductance, winding
resistances and load, the effect would be less pronounced.
The first model uses the basic equations for inductors. The
coils input flux and output ampturns. The core inputs
ampturns and outputs flux.
Simple versions of the circuits for the core and coil are
he
http://www.ivesonaudio.pwp.blueyonde.../CoreModel.GIF
http://www.ivesonaudio.pwp.blueyonde.../CoilModel.GIF
Ian