How to make a Van de Graaff generator with your own hands

American physicist Robert van de Graaf happened to be born and create at the junction of two great scientific eras - electricity and nuclear physics. The generator he created in 1929, which went down in history under his name, was intended for the first physical nuclear research as a particle accelerator. After just two years, the installation was producing discharges up to 7 million volts.

Principle of operation of the Van de Graaff generator

The Van de Graaff generator is one of the first linear accelerators. Nevertheless, anyone who knows a little about electrical engineering can reproduce its current model.

The generator consists of two spheres, to which positive and negative charges are applied, a dielectric looped tape stretched over 2 rotating rollers (upper and lower), two electrodes in the form of brushes located near the rollers, with the upper electrode closed to the inner surface of the sphere, and the lower connected to a high voltage source.

The device starts to work with the rotation of the belt stretched over the rollers. The top roller is made of dielectric material and the bottom roller is made of grounded metal. The upper electrode is connected to a metal sphere, and the lower, connected to a high voltage source, ionizes the surrounding air and creates positive ions that "stick" to the moving belt.

It, like a conveyor, "delivers" positive charges "upward", where the brush electrode removes them from the roller, transferring them to the inner surface of the sphere, where the charges accumulate.

At the same time, negative charges are accumulating on the other sphere. As soon as the accumulated potential reaches a critical level, an electrical discharge occurs.

At the dawn of the nuclear age, the Van de Graaff generator was used for some time as a linear particle accelerator. But his active scientific "career" did not last long. Very soon, a new generation of accelerators appeared, incommensurate in power and capabilities with their predecessor.

However, unlike its "peers", electrical devices of the middle of the last century, written off for scrap, the Van de Graaff generator leads a rather active life. From leading research centers, he moved to school physical classes and institute laboratories, becoming, for example, an irreplaceable teaching aid for modeling natural discharges in a gas environment.

Perhaps one of the most famous experiments is called "hair on end." To do this, you need to stand on a rubber mat or wooden board and touch the switched on Van de Graaff generator. Owners of lush hair will have a surprise worthy of a photo with subsequent posting on Instagram.

DIY Van de Graaff generator

It embodies the well-known thesis: "All ingenious is simple." On YouTube and on Internet sites, you can find dozens of variants of operating Van de Graaff generators, made by craftsmen from absolutely accessible materials at hand - pencils, scraps of PVC water pipes, rubber bands, paper clips, batteries, electric motors from toys, tape, wires, etc. e. This list is limited only by the imagination and qualifications of inventors.

The most affordable option is with a PVC pipe cut, inside which rotating rollers are attached to the axles, interconnected by a strong tape. To establish the axes, it is necessary to make parallel holes at the top and bottom using a heated soldering iron.

Another hole for the brush is made perpendicular to the lower axis. The lower roller and brush are connected to an electric motor. As a sphere, you can use a used soda can with a capacity of 0.33 liters. A brush is attached to the side facing the inside of the pipe to remove the positive charge. After that, the structure is assembled. Everything, you can run. After a couple of minutes, you should bring the sphere-jar to a stream of water, and it will slightly deflect under the influence of the magnetic field. Q.E.D.