A. Primary Winding only
B. Secondary Winding only
C. Transformer core only
D. Both Primary and Secondary Windings
Answer: D. Both Primary and Secondary Windings
Explanation:
When an alternating voltage ( VP ) is applied to the primary coil, current flows through the coil which in turn sets up a magnetic field around itself, called mutual inductance, by this current flow according to Faraday’s Law of electromagnetic induction.
The strength of the magnetic field builds up as the current flow rises from zero to its maximum value which is given as dΦ/dt.
As the magnetic lines of force setup by this electromagnet expand outward from the coil the soft iron core forms a path for and concentrates the magnetic flux.
This magnetic flux links the turns of both windings as it increases and decreases in opposite directions under the influence of the AC supply.
However, the strength of the magnetic field induced into the soft iron core depends upon the amount of current and the number of turns in the winding.
When current is reduced, the magnetic field strength reduces.