The dynamo, as a general concept of an electrical generator, was invented by Michael Faraday in 1831. He built the first electromagnetic generator known as the Faraday disk, which was a conducting disc rotating between the poles of a magnet and induced an electric current by electromagnetic induction. This invention laid the foundation for the dynamo principle.

The modern dynamo, suitable for industrial applications and capable of generating continuous direct current, was further developed and industrialized by Zénobe-Théophile Gramme in 1869-1871. Gramme invented the Gramme dynamo, which was a significant improvement capable of producing higher voltages and useful for commercial power generation, making a major impact on electric power development.

In summary:

• Michael Faraday invented the basic dynamo concept and first electromagnetic generator in 1831.
• Zénobe-Théophile Gramme invented the practical industrial dynamo that enabled widespread use in the late 19th century.