There are two types of electric current - direct current (DC) and alternating current (AC).
An electric current can be produced by moving a magnet inside a coil of wire. The size of this induced current can be increased by moving the magnet faster, by using a stronger magnet, or by increasing the number of turns on the coil and increasing its area.
A dynamo is one type of electricity generator.
[ This page has been adapted from www.bbc.co.uk/schools/gcsebitesize/science