Home > Encyclopedia of Science > Generator

• Principle of operation
• Words to Know
• Alternating current (AC) generators
• Direct current (DC) generators

A generator is a machine that converts mechanical energy into electrical energy. Generators can be subdivided into two major categories depending on whether the electric current produced is alternating current (AC) or direct current (DC). The basic principle on which both types of generators work is the same, although the details of construction of the two may differ somewhat.

Principle of operation

In 1820, Danish physicist Hans Christian Oersted (1777–1851) discovered that an electric current created a magnetic field around it. French physicist André Marie Amperè (1775–1836) then found...