On this day, 194 years ago, on September 23, 1831 (August 18, 1831, the lunar calendar), Faraday invented the generator. On September 23, 1831, Faraday invented the generator. British scientist Faraday discovered the principle of electromagnetic induction in 1831. This principle that plays an important role in the development of human society says: "When the magnetic field lines change, current will be induced in the wires around it. Faraday had taken great pains, through research and repeated experiments, and finally discovered this influential scientific principle, and he was convinced that using this principle would definitely be used to create a generator that could actually generate electricity. A generator is a device that converts mechanical energy into electrical energy. The energy contained in various primary energy sources is first converted into mechanical energy through the prime mover, then converted into electrical energy through the generator, and sent to various power consumption occasions through the transmission and distribution network. Due to different forms of primary energy, different generators can be made. Hydrogenerator can be made by using the cooperation of water conservancy resources and water turbines; Due to different reservoir capacities and head drops, hydro-generators with different capacities and rotational speeds can be made. Using coal, oil and other resources, combined with boilers and gas turbines, turbogenerators can be made. Most of these generators are high-speed motors (3000rpm). In addition, there are various generators that use wind energy, atomic energy, geothermal energy and other energy. In addition, due to the different working principles of generators, they are divided into DC generators, asynchronous generators and synchronous generators. The large generators currently widely used are synchronous generators. Comment: Electricity has enabled mankind to truly enter the era of civilization.