A car dynamo converts mechanical energy into electrical energy. The dynamo uses a coil of metal wire rotated within a magnetic field to convert the mechanical energy into direct current using Faraday’s law.
There are three main parts to the dynamo. The stator is the main housing unit, where the magnetic field is kept constant. The armature is the metal coils that are rotated by mechanical force. The commutator is a set of contacts on the armature’s shaft which reverses the electrical potential in the metal wire with every half turn of the armature, converting alternating current into direct current. In modern times, alternating current is mainly used because it is so easily converted by solid state materials.
The electric generator, which became the dynamo, was created by Michael Faraday in 1831. It began as a copper disc that was rotated between magnets. It is not considered a dynamo because it did not utilize a commutator. It did, however, create very low amounts of electric due to the single current path through a magnetic field. Faraday, with the help of others, discovered that more voltage could be created by winding multiple turns of a wire into a coil. The amount of voltage produced depends on the amount of turns. The dynamo eventually led to the invention of the electrical generators used today. Hand-cranked dynamos are still used today in handheld devices, such as hand-cranked radios, flashlights and watches. There are even hand-cranked dynamos that connect to mobile phones via USB.