We all know that magnets are attracted by opposite poles and repelled by the same name. And if you take two magnets, for example, from furniture latches, and simply put them on the table so that their magnetization vectors are directed in different directions (one magnet with the north pole up, the other with the south), and try to bring the magnets closer, then it’s easy to find that they will be attracted, and there is nothing surprising in this.

Now let's move on. Take a few magnets from furniture latches, and make high stacks of them, which we place in a similar way. Obviously, the picture is similar. Now take a stack and a single magnet - a single magnet is attracted to the stack. But what will happen if the stack is not solid, but divided in the middle by a gasket, for example a cardboard, the thickness of a single magnet? In this case, we get additional poles ...

Why is the transformer humming? Have you ever thought about this? Someone will say that this is because the coils are poorly fixed between themselves or the windings oscillate, knocking on iron. Maybe the core area turned out to be less than the required by calculations, or did too many volts per turn turn out during winding? Does the frequency supplied correspond to this core material? Let’s understand, however.

In fact, the cause of transformer humming is initially magnetostriction. Magnetostriction is the phenomenon of changes in the size and shape of a ferromagnetic body under the influence of an alternating magnetic field. In addition to magnetostriction, noise can be caused by working oil pumps and fans of cooling systems of powerful transformers. The electrodynamic forces in the windings and the electromechanical devices that regulate the voltage under load also create noise ...

This article is for informational purposes only. The devices described here are potentially life-threatening, so please be careful when using this information.

A Marx generator is a device for producing high-voltage pulsed discharges, based on the principle of parallel charging several high-voltage capacitors to a high voltage, followed by connecting these charged capacitors to a series circuit, as a result of this addition, a spark electric discharge is obtained at a voltage higher than the voltage of the charging source, in proportion the number of capacitors in the circuit.

Capacitors are charged in parallel through high-resistance (megaohm) resistors, and series connection is made possible by the use of gas (air) arresters ...

The phenomenon of the emergence of thermo-EMF was discovered by the German physicist Thomas Johann Seebeck back in 1821. And this phenomenon consists in the fact that in a closed electric circuit consisting of heterogeneous conductors connected in series, provided that their contacts are at different temperatures, an EMF occurs. This effect, named after its discoverer, the Seebeck effect, is now called simply the thermoelectric effect.

If the circuit consists of only a pair of dissimilar conductors, then such a circuit is called a thermocouple. In a first approximation, it can be argued that the magnitude of the thermo-emf depends only on the material of the conductors and on the temperatures of the cold and hot contacts. Thus, in a small temperature range, thermo-EMF is proportional to the temperature difference between cold and hot contacts, and the proportionality coefficient in the formula is called the coefficient ...

Today, the Tesla transformer is called a high-frequency high-voltage resonant transformer, and in the network you can find many examples of vivid implementations of this unusual device. A coil without a ferromagnetic core, consisting of many turns of a thin wire, crowned with a torus, emits real lightning, impressing amazed spectators. But do everyone remember how and why this amazing device was originally created?

The history of this invention begins from the end of the 19th century, when the ingenious scientist-experimenter Nikola Tesla, working in the United States, only set himself the task of learning how to transmit electrical energy over long distances without wires. It is hardly possible to pinpoint the exact year when this idea came to the scientist for sure, but it is known that on May 20, 1891, Nikola Tesla delivered a detailed lecture at Columbia University ...

Everyone who watched the Back to the Future trilogy probably remembers how Marty McFly escaped the chase on a hoverboard soaring. To this day, the idea of ​​recreating a hoverboard excites the minds of many inventors - enthusiasts. Even Lexus did not neglect this idea. However, not only Lexus achieved their goal on the way of translating this fantastic vehicle into reality, but first things first.

At the end of 2014, after successfully collecting $ 500,000 on kickstarter, Greg and Jill Hendersons realized their plan. By creating Arx Pax, the couple finally built the world's first hoverboard, which they named Hendo Hover. The skateboard hover technology is based on the repulsion of magnetic fields, which creates a counteraction to the force of gravity. About the same way soar trains on a magnetic cushion, the only difference is ...

Rare, and in particular rare earth, metals are very widely used in various high-tech industries. Mechanical engineering, metallurgy, chemical industry, solar energy, nuclear and hydrogen energy, instrument making, electronics - rare earth metals are used everywhere. It is possible to enumerate all areas of application of rare-earth metals for a very long time, however, let us consider part of this vast spectrum as applied directly to electronics and electric power industry.

The volume of rare-earth metals used not only in computer technology, but also in economical light sources is growing every year. For example, in the USA, due to this, they predict a 2-fold decrease in energy consumption for lighting. Lamps with phosphors containing terbium, yttrium, cerium, europium have already been created there, which allowed up to 3 times higher light output ...

Initially, superconductors had a very limited application, since their operating temperature should not exceed 20K (-253 ° C). For example, the temperature of liquid helium at 4.2 K (-268.8 ° C) is well suited for the superconductor to work, but it takes a lot of energy to cool and maintain such a low temperature, which is technically very problematic.

The high-temperature superconductors discovered in 1986 by Karl Müller and Georg Bednorets showed a critical temperature much higher, and the temperature of liquid nitrogen at 75K (-198 ° C) for such conductors is quite enough for operation. In addition, nitrogen is much cheaper than helium as a refrigerant.

The discovery in 1987 of a "jump in conductivity to almost zero" at a temperature of 36K (-237 ° C) for compounds of lanthanum, strontium, copper and oxygen was the beginning. Then, for the first time, the property of compounds of yttrium, barium, copper, and oxygen to reveal superconducting properties was discovered ...