ALTERNATING CURRENTS The transformer.

THE TRANSFORMER
The current through the primary coil, induces a magnetic field of strength proportional to its number of turns N_p, this causes an induce e.m.f. in the secondary coil, again the strength is proportional to the number of turns on the secondary coil N_s. The ratio of the voltages is equal to ratio of the turns.

^Vs /V_p = ^Ns / N_p An iron core is used so the permeability is greater.

Note: this is a perfect situation in real life energy would be lost due to

Resistance of the wire in the coil.
Eddy currents induced in the iron core.

Rob Coles 30 May 1996 13:54:09