Generators and motors
Principle of a generator: rotating loop of wire in magnetic field
While the loop is rotating the number of field lines within the loop changes --> induces voltage between the two ends of the wire
The voltage is an oscillating one
A simple change in the way the voltage is carried to the external circuits (with a commutator) converts the generator to produce pulsating direct current
Electric motor: basically a generator run backward (we apply voltage at the end of the wires, causing the loop to rotate!)