**Bicycle Dynamo**

A hub dynamo is a small electrical generator built into the hub of a bicycle wheel that is usually used to power lights. Note that the hub dynamo is (usually) not actually a dynamo, which creates DC, but a low-power magneto that creates AC. Most modern hub dynamos are regulated to 3 watts at 6 volts, although some will drive up to 6 watts at 12 volts.

An ac generator consists of a coil - or coils - of wire moving relative to a magnetic field. With this arrangement, a voltage is induced and this generates a current in a circuit.

In a bicycle dynamo, a magnet turns inside a coil of wire when the back wheel of the bicycle is turning.

In a bicycle dynamo, a magnet turns inside a coil of wire when the back wheel of the bicycle is turning.

## Faraday's Law

Faraday's law of induction is a basic law of electromagnetism predicting how a magnetic field will interact with an electric circuit to produce an electromotive force (EMF)—a phenomenon called electromagnetic induction. It is the fundamental operating principle of transformers, inductors, and many types of electrical motors, generators and solenoids.

The Maxwell–Faraday equation is a generalization of Faraday's law, and forms one of Maxwell's equations.

The Maxwell–Faraday equation is a generalization of Faraday's law, and forms one of Maxwell's equations.