Dynamos and Generators convert mechanical rotation into electric power. Dynamo - a device that makes direct current electric power using electromagnetism. It is also known as a generator, however the term generator normally refers to an "alternator" which creates alternating current power.
How does a bicycle dynamo generate current?
Instead, generators induce a current by spinning a coil of wire inside a magnetic field, or by spinning a magnet inside a coil of wire. One simple example of a generator is the bicycle dynamo. The dynamo has a wheel that touches the back tyre. As the bicycle moves, the wheel turns a magnet inside a coil.
Is a dynamo the same as an alternator?
Both dynamos and alternators use the same concept of electromagnetic fields to produce power. The main difference between dynamos and alternator is the type of current they produce. Without a commutator, a dynamo would simply produce alternating current just like an alternator.