<P> A varying current in the transformer 's primary winding creates a varying magnetic flux in the transformer core and a varying magnetic field impinging on the secondary winding . This varying magnetic field at the secondary winding induces a varying EMF or voltage in the secondary winding due to electromagnetic induction . The primary and secondary windings are wrapped around a core of infinitely high magnetic permeability so that all of the magnetic flux passes through both the primary and secondary windings . With a voltage source connected to the primary winding and load impedance connected to the secondary winding , the transformer currents flow in the indicated directions . ( See also Polarity . ) </P>
<P> A varying current in the transformer 's primary winding creates a varying magnetic flux in the transformer core and a varying magnetic field impinging on the secondary winding . This varying magnetic field at the secondary winding induces a varying EMF or voltage in the secondary winding due to electromagnetic induction . The primary and secondary windings are wrapped around a core of infinitely high magnetic permeability so that all of the magnetic flux passes through both the primary and secondary windings . With a voltage source connected to the primary winding and load impedance connected to the secondary winding , the transformer currents flow in the indicated directions . ( See also Polarity . ) </P>
what is the purpose of the primary windings of a transformer
what is the purpose of the primary windings of a transformer
a varying magnetic field
a varying magnetic field