In research related to the field of Modern Physics, it is necessary to use very high voltages, voltages that can reach millions of volts. These voltages are used to accelerate electrified particles such as electrons, causing these particles to reach great speeds. After reaching such speeds, the particles are launched against atomic nuclei, thus causing nuclear reactions that are then studied by physicists.
It was thinking about achieving high voltages that, in 1929, the American physicist Robert Jemison Van de Graaff built the first model of a generator, which ended up being named the Van de Graaff Generator in his honor. This device had, and still has, wide application in atomic physics as well as in medicine and industry. In high school and higher education laboratories, simplified models of this generator are used for the purposes of electricity demonstrations.
This generator is composed of:
• A motor;
• Two cylinders;
• A set of straps;
• A set of brushes;
• An output terminal, which is most often a large metal or aluminum sphere.
The Van de Graaff generator works by moving a belt that is electrified by friction at the bottom of the device. Upon reaching the upper part, the electrical charges, which emerged with the electrification process, are transferred to the inner surface of the metal, being then distributed to the entire surface of the metallic sphere, becoming charged with electrical charges. If, during the generator’s operation, we bring our finger or a metal object closer, we will perceive light electrical discharges that occur due to the potential difference (ddp).