Electrostatic generator

In 1931 the American scientist G. van de Graaff invented an electrostatic generator for wide practical application. The moving belt of a dielectric material, passes a metallic bullet charge, which gradually increases to several million volts. Generator van de Graaff is used during the testing of insulators and other equipment, designed for high voltage, and in nuclear studies, the high voltage is used for acceleration of charged subatomic particles.
Although frictional and induction machines can create high voltage, they were unfit to produce a strong direct current. This problem was solved in the late 1790s, Italian scientist Alessandro Volta invented the first battery. Further improvements gave the opportunity to use electricity for lighting (the end of XIX century). Although batteries are a convenient and versatile source of electricity, they are gradually discharged and require replacement or recharging. They can't afford the large settlements the electricity needed for lighting, heating and other necessities. Experiments conducted in the early nineteenth century, led to the creation of modern generators.