The principle of operation of a tesla coil. Tesla generator - an ideal source of energy

Operation of CRT TVs, fluorescent and energy saving light bulbs, remote battery charging is provided special device- Tesla transformer (coil). To create spectacular light charges purple, reminiscent of lightning, a Tesla coil is also used. The 220 V circuit allows you to understand the structure of this device and, if necessary, make it yourself.

Mechanism of operation

A Tesla coil is an electrical device capable of increasing voltage and current frequency several times. During its operation, a magnetic field is formed, which can affect electrical engineering and the human condition. Discharges entering the air contribute to the release of ozone. The transformer design consists of the following elements:

• Primary coil. It has an average of 5-7 turns of wire with a cross-sectional diameter of at least 6 mm².
• Secondary coil. Consists of 70−100 turns of dielectric with a diameter of no more than 0.3 mm.
• Capacitor.
• Discharger.
• Spark glow emitter.

The transformer, created and patented by Nikola Tesla in 1896, does not have ferroalloys, which are used for cores in other similar devices. The power of the coil is limited by the electrical strength of the air and does not depend on the power of the voltage source.

When voltage hits the primary circuit, high-frequency oscillations are generated on it. Thanks to them, resonant oscillations occur on the secondary coil, which results in an electric current characterized by high voltage and high frequency. The passage of this current through the air leads to the appearance streamer- a purple discharge resembling lightning.

Circuit oscillations that occur during the operation of a Tesla coil can be generated in different ways. Most often this happens using a spark gap, lamp or transistor. The most powerful devices are those that use double resonance generators.

Source materials

For a person with basic knowledge of physics and electrical engineering, it will not be difficult to assemble a Tesla transformer with your own hands. You just need to prepare a set of basic parts:

A mandatory element of the primary coil is a cooling radiator, the size of which directly affects the cooling efficiency of the equipment. A copper tube or wire with a diameter of 5-10 mm can be used as a winding.

The secondary coil requires mandatory insulation in the form of treatment with paint, varnish or other dielectric. An additional part of this circuit is a series-connected terminal. Its use is advisable only for powerful discharges; for small streamers, it is enough to move the end of the winding upward by 0.5-5 cm.

Connection diagram

The Tesla transformer is assembled and connected in accordance with electrical diagram. Installation of a low-power device should be carried out in several stages:

The assembly of a more powerful transformer follows a similar scheme. To achieve high power, will be required:

The maximum power that can be reached correctly assembled transformer Tesla, reaches 4.5 kW. This indicator can be achieved by equalizing the frequencies of both circuits.

A self-assembled Tesla coil must be checked. During test connection follows:

1. Install variable resistor to the middle position.
2. Monitor the presence of a discharge. If it is absent, you need to bring a fluorescent lamp or incandescent lamp to the coil. Its glow will indicate the presence of electrical magnetic field and about the performance of the transformer. Also, the serviceability of the device can be determined by self-igniting radio lamps and flashes at the end of the emitter.

The first start-up of the device should be carried out while monitoring the temperature. At high heat additional cooling is required.

Transformer Application

The coil can create different types charges. Most often, during its operation, a charge appears in the form of an arc.

Glow of air ions in electric field with increased voltage is called corona discharge. It is a bluish radiation formed around coil parts that have significant surface curvature.

A spark discharge or spark passes from the transformer terminal to the surface of the earth or to a grounded object in the form of a bunch of bright stripes that quickly change shape and go out.

The streamer looks like a thin, weakly glowing light channel, which has many branches and consists of free electrons and ionized gas particles that do not go into the ground, but flow through the air.

Creation various kinds electrical discharges using a Tesla coil occur with a large increase in current and energy, causing a crackling sound. The expansion of the channels of some discharges provokes an increase in pressure and the formation of a shock wave. The combination of shock waves sounds like the crackle of sparks when a flame burns.

Transformer effect this kind was previously used in medicine to treat diseases. High-frequency current flowing through human skin gave a healing and tonic effect. It turned out to be useful only under conditions of low power. When the power increased to high values, the opposite result was obtained, negatively affecting the body.

Using such an electrical device, gas-discharge lamps are ignited and leaks are detected in the vacuum space. It is also successfully used in the military sphere for the purpose of quickly destroying electrical equipment on ships, tanks or buildings. A powerful pulse generated by the coil in a very short period disables microcircuits, transistors and other devices located within a radius of tens of meters. The process of destroying equipment occurs silently.

The most spectacular area of ​​application is demonstrative light shows. All effects are created due to the formation of powerful air charges, the length of which is measured in several meters. This property allows the transformer to be widely used when filming films and creating computer games.

When developing this device, Nikola Tesla planned to use it to transmit energy on a global scale. The scientist’s idea was based on the use of two strong transformers, located at different ends of the Earth and operating with an equal resonant frequency.

If such a power transmission system were successfully used, the need for power plants, copper cables and electricity suppliers would be completely eliminated. Every inhabitant of the planet would be able to use electricity anywhere absolutely free of charge. However, due to economic unprofitability, the famous physicist’s plan has not yet been (and is unlikely to ever be) realized.

Tesla coil

Discharges from the wire at the terminal

Transformer Tesla- the only one of Nikola Tesla's inventions that bears his name today. This is a classic resonant transformer, producing high voltage at high frequency. It was used by Tesla in several sizes and variations for his experiments. Tesla Transformer is also known as Tesla Coil. Tesla coil). In Russia the following abbreviations are often used: TS (from Tesla coil), CT (Tesla coil), just Tesla and even affectionately - Katka. The device was declared by patent No. 568176 dated September 22, 1896, as “Apparatus for producing electric currents of high frequency and potential.”

Description of design

Diagram of the simplest Tesla transformer

In its elementary form, a Tesla transformer consists of two coils, primary and secondary, and a harness consisting of a spark gap (chopper, the English version of Spark Gap is often found), a capacitor, a toroid (not always used) and a terminal (shown as “output” in the diagram) .

The primary coil is built from 5-30 (for VTTC - Tesla coil on a lamp - the number of turns can reach 60) turns of large diameter wire or copper tube, and the secondary is made of many turns of smaller diameter wire. The primary coil can be flat (horizontal), conical or cylindrical (vertical). Unlike many other transformers, there is no ferromagnetic core. Thus, the mutual inductance between the two coils is much less than that of conventional transformers with a ferromagnetic core. This transformer also has virtually no magnetic hysteresis, the phenomenon of delay in changes in magnetic induction relative to changes in current, and other disadvantages introduced by the presence of a ferromagnet in the field of the transformer.

The primary coil together with the capacitor forms an oscillatory circuit, which includes a nonlinear element - a spark gap (spark gap). The arrester, in the simplest case, is an ordinary gas one; usually made of massive electrodes (sometimes with radiators), which is made for greater wear resistance when large currents flow through an electric arc between them.

The secondary coil also forms an oscillatory circuit, where the role of a capacitor is played by the capacitive connection between the toroid, the terminal device, the turns of the coil itself and other electrically conductive elements of the circuit with the Earth. The final device (terminal) can be made in the form of a disk, a sharpened pin or a sphere. The terminal is designed to produce predictable spark discharges of long length. The geometry and relative position of the parts of a Tesla transformer greatly influences its performance, which is similar to the problems of designing any high-voltage and high-frequency devices.

Operation

Tesla transformer in question simplest design shown in the diagram operates in pulse mode. The first phase is the charging of the capacitor to the breakdown voltage of the spark gap. The second phase is the generation of high-frequency oscillations.

Charge

The capacitor is charged by an external source high voltage, protected by chokes and usually built on the basis of a step-up low-frequency transformer. Since part of the electrical energy accumulated in the capacitor will be used to generate high-frequency oscillations, they try to maximize the capacitance and maximum voltage on the capacitor. The charging voltage is limited by the breakdown voltage of the spark gap, which (in the case of an air spark gap) can be adjusted by changing the distance between the electrodes or their shape. The typical maximum capacitor charge voltage is 2-20 kilovolts. The sign of the voltage for the charge is usually not important, since electrolytic capacitors are not used in high-frequency oscillatory circuits. Moreover, in many designs, the sign of the charge changes with the frequency of the household power supply network (or Hz).

Generation

After the breakdown voltage is reached between the electrodes of the spark gap, an avalanche-like electrical breakdown of the gas occurs in it. The capacitor is discharged through a spark gap onto the coil. After the capacitor is discharged, the breakdown voltage of the spark gap decreases sharply due to the charge carriers remaining in the gas. In practice, the oscillatory circuit of the primary coil remains closed through the spark gap as long as the current creates a sufficient number of charge carriers to maintain a breakdown voltage significantly less than the amplitude of the oscillation voltage in the LC circuit. The oscillations gradually die out, mainly due to losses in the spark gap and the loss of electromagnetic energy to the secondary coil. Resonant oscillations occur in the secondary circuit, which leads to the appearance of high-voltage high-frequency voltage at the terminal!

As an RF voltage generator, modern Tesla transformers use tube (VTTC - Vacuum Tube Tesla Coil) and transistor (SSTC - Solid State Tesla Coil, DRSSTC - Dual Resonance SSTC) generators. This makes it possible to reduce the dimensions of the installation, increase controllability, reduce noise levels and get rid of the spark gap. There is also a variety of Tesla transformers powered by DC. The abbreviations of the names of such coils contain the letters DC, for example DC DRSSTC. IN separate category Also include Tesla magnet coils.

Many developers use controlled electronic components, such as transistors, modules on MOSFET transistors, vacuum tubes, thyristors, as a breaker (discharger).

Using a Tesla Transformer

Tesla transformer discharge

Discharge from the end of the wire

The output voltage of a Tesla transformer can reach several million volts. This voltage at a resonant frequency is capable of creating impressive electrical discharges in the air, which can be many meters long. These phenomena fascinate people various reasons, therefore the Tesla transformer is used as a decorative product.

The transformer was used by Tesla to generate and propagate electrical oscillations aimed at controlling devices over a distance without wires (radio control), wirelessly transmitting data (radio), and wirelessly transmitting power. At the beginning of the 20th century, Tesla's transformer also found popular use in medicine. Patients were treated with weak high-frequency currents, which flow through a thin layer of the skin surface and do not cause harm. internal organs(see Skin effect), while providing a tonic and healing effect. Recent studies of the mechanism of action of powerful HF currents on a living organism have shown the negativity of their influence.

Tesla's transformer is not widely available these days. practical application. It is produced by many fans of high-voltage equipment and the effects that accompany its operation. It is also sometimes used for ignition gas discharge lamps and for finding leaks in vacuum systems.

The Tesla transformer is used by the military to quickly destroy all electronics in a building, tank, or ship. A powerful electromagnetic pulse is created for a split second within a radius of several tens of meters. As a result, all microcircuits and transistors and semiconductor electronics burn out. This device it operates completely silently. A message appeared in the press that the current frequency reaches 1 Terahertz.

Effects observed during operation of the Tesla transformer

During operation, the Tesla coil creates beautiful effects associated with the formation various types gas discharges. Many people collect Tesla transformers just to look at these impressive, beautiful phenomena. In general, the Tesla coil produces 4 types of discharges:

1. Streamers (from English. Streamer) - dimly glowing thin branched channels that contain ionized gas atoms and free electrons split off from them. It flows from the terminal (or from the sharpest, curved explosive parts) of the coil directly into the air, without going into the ground, since the charge evenly flows from the discharge surface through the air into the ground. A streamer is, in fact, visible ionization of air (glow of ions) created by the high-voltage field of a transformer.
2. Spark (from English. Spark) is a spark discharge. It goes from the terminal (or from the sharpest, curved explosive parts) directly into the ground or into a grounded object. It is a bunch of bright, quickly disappearing or replacing each other thread-like, often highly branched stripes - spark channels. It also takes place special kind spark discharge - sliding spark discharge.
3. Corona discharge is the glow of air ions in a high voltage electric field. Creates a beautiful bluish glow around explosive parts of a structure with a strong surface curvature.
4. Arc discharge - occurs in many cases. For example, with sufficient transformer power, if a grounded object is brought close to its terminal, an arc may light up between it and the terminal (sometimes you need to directly touch the terminal with the object and then stretch the arc, moving the object to a greater distance). This is especially true for Tesla tube coils. If the coil is not powerful and reliable enough, the arcing generated can damage its components.

You can often observe (especially near powerful coils) how discharges come not only from the coil itself (its terminal, etc.), but also towards it from grounded objects. Corona discharge may also occur on such objects. Rarely, a glow discharge can also be observed. It is interesting to note that different chemicals, applied to the discharge terminal, are capable of changing the color of the discharge. For example, sodium changes its normal spark color to orange, and bromine changes its normal color to green.

The operation of a resonant transformer is accompanied by a characteristic electrical crackling sound. The appearance of this phenomenon is associated with the transformation of streamers into spark channels (see the article spark discharge), which is accompanied by a sharp increase in the current strength and the amount of energy released in them. Each channel rapidly expands, the pressure in it increases abruptly, as a result of which a shock wave appears at its boundaries. The combination of shock waves from the expanding spark channels generates a sound perceived as the “crack” of a spark.

Unknown effects of Tesla's transformer

Many people believe that Tesla coils are special artifacts with exceptional properties. There is an opinion that the Tesla transformer can be a generator free energy and is a perpetual motion machine, based on the fact that Tesla himself believed that his generator takes energy from the ether (special invisible matter in which electromagnetic waves propagate) through the spark gap. Sometimes you can hear that using a Tesla Coil you can create anti-gravity and effectively transmit electricity over long distances without wires. These properties have not yet been tested or confirmed by science. However, Tesla himself said that such abilities would soon be available to humanity with the help of his inventions. But later I decided that people were not ready for this.

It is also a very common thesis that the discharges emitted by Tesla transformers are completely safe and can be touched with your hands. This is not entirely true. In medicine, Tesla coils are also used to improve skin health. This treatment has positive results and has a beneficial effect on the skin, but the design of medical transformers is very different from the design of conventional ones. Therapeutic generators are distinguished by a very high frequency of output current, at which the thickness of the skin layer (see Skin effect) is safely small, and extremely low power. And the thickness of the skin layer for an average Tesla coil is from 1 mm to 5 mm and its power is enough to heat up this layer of skin and disrupt the natural chemical processes. With prolonged exposure to such currents, serious chronic diseases, malignant tumors and others negative consequences. In addition, it should be noted that being in the HF field of a coil (even without direct contact with current) can negatively affect health. It's important to note that nervous system a person does not perceive high-frequency current and pain is not felt, but nevertheless this can mark the beginning of processes that are destructive for a person. There is also a danger of poisoning from gases generated during operation of the transformer in a closed room without an influx fresh air. Plus, you can get burned, since the temperature of the discharge is usually enough for a small burn (and sometimes for a large one), and if a person still wants to “catch” the discharge, then this should be done through some kind of conductor (for example, a metal rod) . In this case, there will be no direct contact of the hot discharge with the skin, and the current will first flow through the conductor and only then through the body.

Tesla Transformer in Culture

In Jim Jarmusch's film Coffee and Cigarettes, one of the episodes is based on a demonstration of the Tesla transformer. In the story, Jack White, guitarist and vocalist of The White Stripes, tells Meg White, the band's drummer, that the earth is a conductor of acoustic resonance (the theory of electromagnetic resonance - an idea that occupied Tesla's mind for many years), and then "Jack demonstrates Meg Tesla car."

In Command & Conquer: Red Alert, the Soviets can build a defensive structure in the form of a tower with a spiral wire that strikes the enemy with powerful electrical discharges. There are also tanks and infantrymen in the game that use this technology. Tesla coil (in one translation - Tesla tower) is an exceptionally accurate, powerful and long-range weapon in the game, but consumes a relatively high amount of energy. To increase the power and range of destruction, you can “charge” the towers. To do this, give the order to the Tesla Warrior (this is an infantryman) to come and stand next to the tower. When the warrior reaches the location, he will begin charging the tower. In this case, the animation will be the same as during an attack, but the lightning from his hands will be yellow.

It is no secret to anyone who the famous Nikola Tesla is. Mystical stories that talk about him, we are not discussing today. Let's remember the famous inventions that are still debated to this day.

Major inventions

• Wireless energy transfer over long distances;
• Fluorescent glow;
• Electric clock;
• Turbine;
• Electric ovens;
• Fluorescent lamps;
• Electron microscope.

It is simply impossible to list all of his 800 inventions. One of the inventions that amazes with bright phenomena in the form of lightning-shaped flashes is considered to be high-frequency Tesla coils. They are a resonant transformer. This device has been impressing with the power of large discharges for decades. Having seen the operation of the device, you will not be able to forget the amazing phenomenon that creates bright light effects that resemble controlled lightning. Using coils 60 meters in diameter and a pole made of a copper sphere, Tesla placed them above the laboratory and generated discharges. Their length reached more than forty meters.

Such arrows created effects incredible beauty, while the sound of thunder (released energy) was heard 25 kilometers away. A luminous ball with a diameter of at least 30 meters floated above the tower. People were amazed by the extraordinary spectacle of sparks dancing across the ground. In addition, when anyone tried to open a water tap, they received an armful of colored lights. A similar experimental launch took place in 1904.

If you are an amateur specialist, you have a cherished dream of repeating the work of a brilliant inventor, then we will try to figure out how to assemble a Tesla coil. Despite the fact that the work itself is not difficult, many cannot cope with it. In order for everything to work out, you need to know the principle of operation of the Tesla coil. The device has several names, but they all mean the same thing:

• Tesla Transformer (main name);
• Tesla Coil;
• Tesla.

The principle of operation of a Tesla coil.

It should be remembered that this is a universal transformer design, which is made of two windings that do not have a common core, since it enhances mutual induction. The first (primary) coil, an alternating voltage is supplied to it, which creates a magnetic field. With its help, the received energy of the primary coil is transferred to the second winding.

The second model also creates a circuit (oscillatory), but the difference is that the condensate replaces the capacitance of the toroid. All received energy is stored in a given circuit in the form of voltage for a certain time. This leads to the conclusion: the more energy we accumulate, the higher the resulting voltage will be. The output is no less than millions of volts. This makes it possible to observe the amazing spectacle of electrical discharges. The pulse length reaches several meters. To replicate the invention, the first question that arises is how to assemble a Tesla coil. To do this you will need:

1. Toroid. Performs three main functions - reduces resonant frequencies, creates energy accumulation, and forms magnetic fields. Toroids are produced from aluminum steel or corrugation;
2. The secondary coil model (main part) must have significant inductance;
3. Primary low inductive coil. Copper pipes are used for manufacturing;
4. The protective ring is used to prevent damage to the electronics;
5. Mandatory grounding;
6. Metal wire having different diameters;

Once you have prepared all the required material, proceed to step by step creation inventions.

The work begins with the winding.

In order to make a winding on the first coil, prepare a special form. It should be conical or cylindrical. Wind a wire around copper alloy. There should be at least ten revolutions. The turns should be made tightly, but at the same time it must be controlled so that there are no overlaps. After finishing the winding, be sure to insulate and strengthen the resulting turns using varnish. Remember!!! The length of the wire affects the inductance, and it must only be low on the first coil.

The secondary model is created in a similar way, but the number of turns increases. There should be at least a thousand of them, while the transformation coefficient is fifty times greater in the quantitative ratio of the second winding to the primary. The winding of the secondary Tesla coil should be more powerful. But at the same time it must have a frequency equal to the primary winding, since the difference will lead to the combustion of the first coil.

After you have completed the first stage of work, proceed to preparing the transformer. It should be chosen very carefully, it must strictly correspond to the dimensions of the coil. Using small capacitors of equal sizes, combine them together into a circuit. This will give you the potential for even energy storage in the primary circuit. In order for it to be powerful enough, the resulting capacitor must be constantly charged. Having received the main elements, connect everything using a choke. The resulting device will start working only after you connect the transformer.

Types of discharges received:

1. Streamers are thin channels that have large number branches, create a dim glow and contain ionized gas atoms. Discharges are used to ionize the air;
2. Spark is a sliding discharge of sparks;
3. The corona type of discharge is the glow of ions that are in a high voltage electric field;
4. Arc discharge.

Without using wires, using this high-frequency device, you will be able to keep the lamps glowing. In addition, a bright, beautiful spark will be produced at the edge of the winding; you can touch it with your hands, since it is relatively safe. But as experts advise, the transformer device should not be turned on near PCs, telephones or strangers household appliances, as they may fail. If you manage to create such a coil yourself, before starting the test you should adhere to certain rules:

1. The device can damage all electrical appliances that are connected to the electrical network;
2. Stay away from objects made of metal as you may get burned.

Share your knowledge and experience of successfully creating a Tesla coil in

The famous inventor Nikola Tesla has many merits to science and technology, but only one invention bears his name. This is a resonant transformer, also known as a Tesla coil.

A Tesla transformer consists of a primary and secondary winding, a circuit that provides power to the primary winding at the resonant frequency of the secondary, and optionally additional capacitance at the high-voltage output of the secondary winding. The tip, mounted on an additional container, increases the electric field strength, facilitating air breakdown. The additional capacitance reduces the operating frequency, reducing the load on the transistors, and, according to some data, increases the length of the discharges. A piece of sewer PVC pipe is used as the frame of the secondary winding. The secondary winding consists of approximately 810 turns of enameled wire with a diameter of 0.45 mm. The primary winding consists of eight turns of wire with a cross section of 6 mm2. The power circuit is based on the principle of self-oscillation and is built on power transistors.

The essence of Tesla's invention is simple. If a transformer is fed with a current at a frequency equal to the resonant frequency for its secondary winding, the output voltage increases tens and even hundreds of times. In fact, it is limited by the electrical strength of the surrounding air (or other medium) and the transformer itself, as well as losses due to radio wave radiation. The reel is most famous in the field of show business: it is capable of throwing lightning bolts!

Form and content

The transformer looks very unusual - it seems like it was specially designed for show business. Instead of the usual massive iron core with thick windings, there is a long hollow tube made of dielectric, on which the wire is wound in just one layer. This strange appearance is caused by the need to ensure maximum electrical strength of the structure.

Apart from the unusual appearance, the Tesla transformer has one more feature: it necessarily has a certain system that creates a current in the primary winding precisely at the resonant frequency of the secondary. Tesla himself used the so-called spark circuit (SGTC, Spark Gap Tesla Coil). Its principle is to charge the capacitor from a power source and then connect it to the primary winding. Together they create an oscillatory circuit.

The capacitance of the capacitor and the inductance of the winding are selected so that the oscillation frequency in this circuit coincides with the required one. Switching is carried out using a spark gap: as soon as the voltage on the capacitor reaches a certain value, a spark appears in the gap, closing the circuit. You can often see statements that “a spark contains a full spectrum of frequencies, so there is always a resonant one there, which is how the transformer works.” But this is not true - without the correct selection of capacitance and inductance, you cannot get a really high output voltage.

Having decided to make our own Tesla transformer, we settled on a more progressive circuit - a transistor one. Transistor generators potentially allow you to obtain any signal shape and frequency in the primary winding.

The circuit we have chosen consists of a power transistor driver microcircuit, a small transformer to isolate this driver from the 220 V supply voltage, and a half-bridge of two power transistors and two film capacitors. The transformer is wound on a ferrite ring with an operating frequency of at least 500 kHz; three windings of 10-15 turns of wire are made on it. It is very important to connect the transistors to the windings of the transformer so that they operate in antiphase: when one is open, the other is closed.

The required frequency occurs due to feedback from the secondary winding (the circuit is based on self-oscillations). Feedback can be carried out in two ways: using either a current transformer of 50-80 turns of wire on the same ferrite ring as the isolation transformer, through which the ground wire of the lower part of the secondary winding passes, or... just a piece of wire that acts as an antenna, catching radio waves emitted by the secondary winding.

Let's go crazy

As the frame of the primary winding, we took a PVC sewer pipe with a diameter of 9 cm and a length of 50 cm. For winding we use enameled copper wire with a diameter of 0.45 mm. We place the frame and coil of winding wire on two parallel axes. The axis of the frame was a piece of PVC pipe of smaller diameter, and the role of the axis of the coil with the wire was played by a bow arrow lying around in the editorial office.

There are three primary winding options: flat helix, short helical and tapered winding. The first provides maximum electrical strength, but at the expense of inductive coupling strength. The second, on the contrary, creates the best connection, but the higher it is, the greater the chance that a breakdown will occur between it and the secondary winding. Tapered winding is an intermediate option that provides the best balance between inductive coupling and dielectric strength. We didn’t expect to achieve record voltages, so we chose a screw winding: it allows us to achieve maximum efficiency and is easy to manufacture.

As a conductor, we took an audio equipment power cable with a cross-section of 6 mm², eight turns of which were wound onto a piece of PVC pipe of a larger diameter than that of the secondary winding frame, and secured with ordinary electrical tape. This option cannot be considered ideal, because high-frequency current flows only along the surface of the conductors (skin effect), so it is more correct to make the primary winding from copper pipe. But our method is easy to manufacture and works quite well if the power is not too high.

Control

For feedback, we initially planned to use a current transformer. But it turned out to be ineffective at low coil powers. And in the case of an antenna, it is more difficult to provide the initial impulse that will start the oscillations (in the case of a transformer, another wire can be passed through its ring, to which a regular battery can be short-circuited for a split second). In the end we got it mixed system: one output of the transformer was connected to the input of the microcircuit, and the wire of the second was not connected to anything and served as an antenna.

Short circuits, broken transistors and other troubles were initially assumed to be very possible, so an additional control panel with an ammeter was made AC 10 A, an automatic 10 A fuse and a pair of “neons”: one shows whether there is voltage at the input to the remote control, and the other shows whether current is flowing to the coil. Such a remote control allows you to conveniently turn the coil on and off, monitor the main parameters, and also makes it possible to significantly reduce the frequency of trips to the control panel to turn on “knocked out” machines.

The last optional part of the transformer is an additional capacitance in the form of a conducting ball or torus at the high-voltage output of the secondary winding. In many articles you can read that it can significantly lengthen the discharge (by the way, this is wide field for experiments). We made such a 7 pF capacitance by putting together two steel hemispherical cups (from IKEA).

Assembly

Once all components are fabricated, final assembly of the transformer is a breeze. The only subtlety is grounding the lower end of the secondary winding. Alas, not all domestic houses have sockets with separate ground contacts. And where there are, these contacts are not always actually connected (you can check this with a multimeter: there should be about 220 V between the contact and the phase wire, and between it and neutral wire- almost zero).

If you have such sockets (we found them in our editorial office), then you need to ground them with their help, using the appropriate plug to connect the coil. It is often recommended to ground the battery central heating, but this is strictly not recommended, since in some cases it can lead to the fact that the batteries in the house will shock unsuspecting neighbors.

But then comes the crucial moment of switching on... And immediately the first victim of lightning appears - the transistor of the power circuit. After replacement, it turns out that the circuit is, in principle, quite functional, albeit at low powers (200-500 W). When reaching the design power (about 1-2 kW), the transistors explode with a spectacular flash. And although these explosions do not pose a danger, the “one second of operation - 15 minutes of transistor replacement” mode is not satisfactory. Nevertheless, with the help of this transformer you can quite feel yourself in the role of Zeus the Thunderer.

Noble goals

Although today the Tesla transformer, at least in its original form, is most often used in a variety of shows, Nikola Tesla himself created it for much more important purposes. A transformer is a powerful source of radio waves with a frequency from hundreds of kilohertz to several megahertz. Based on Tesla's powerful transformers, it was planned to create a radio broadcasting system, wireless telegraph and wireless telephony.

But Tesla's most ambitious project involving the use of his transformer is the creation of a global wireless power supply system. He believed that a sufficiently powerful transformer or system of transformers would be able to change the charge of the Earth on a global scale and upper layers atmosphere.

In such a situation, a transformer installed anywhere on the planet, having the same resonant frequency as the transmitting one, will be a source of current, and power lines will no longer be needed.

It was the desire to create a wireless power transmission system that ruined the famous Wardenclyff project. Investors were interested in the appearance of only a communication system that would pay off. And the transmitter of energy, which could be uncontrolledly received by anyone around the world, on the contrary, threatened electric companies and wire manufacturers with losses. And one of the main investors was a shareholder of the Niagara hydroelectric power station and copper production plants...

Nikola Tesla is a legendary figure, and the meaning of some of his inventions is still debated to this day. We won’t go into mysticism, but rather talk about how to make something spectacular according to Tesla’s “recipes”. This is a Tesla coil. Having seen it once, you will never forget this incredible and amazing sight!

General information

If we talk about the simplest such transformer (coil), then it consists of two coils that do not have a common core. The primary winding must have at least a dozen turns of thick wire. At least 1000 turns are already wound on the secondary one. Please note that the Tesla coil has one that is 10-50 times greater than the ratio of the number of turns on the second winding to the first.

The output voltage of such a transformer can exceed several million volts. It is this circumstance that ensures the occurrence of spectacular discharges, the length of which can reach several meters at once.

When were the transformer's capabilities first demonstrated to the public?

In the town of Colorado Springs, a generator at a local power plant once completely burned out. The reason was that the current from it went to power the primary winding. During this ingenious experiment, the scientist first proved to the community that the existence of a standing electromagnetic wave- reality. If your dream is a Tesla coil, the most difficult thing to do with your own hands is the primary winding.

In general, making it yourself is not so difficult, but it is much more difficult to give finished product visually attractive appearance.

The simplest transformer

First, you will have to find a high voltage source somewhere, at least 1.5 kV. However, it is best to immediately count on 5 kV. Then we attach it all to a suitable capacitor. If its capacity is too large, you can experiment a little with diode bridges. After this, you make a so-called spark gap, for the sake of which the entire Tesla coil is created.

It’s easy to do: take a couple of wires, and then twist them with electrical tape so that the bare ends point in one direction. We very carefully adjust the gap between them so that the breakdown occurs at a voltage slightly higher than that for the power source. Don't worry: since the current is alternating, the peak voltage will always be slightly higher than stated. After this, the entire structure can be connected to the primary winding.

In this case, to make a secondary one, you can wind only 150-200 turns on any cardboard sleeve. If you do everything correctly, you will get a good discharge, as well as noticeable branching. It is very important to ground the output from the second coil well.

This is how the simplest Tesla coil turned out. Anyone who has at least minimal knowledge of electrical engineering can do it with their own hands.

We design a more “serious” device

All this is good, but how does a transformer work, which is not a shame to show even at some exhibition? Making a more powerful device is quite possible, but it will require a lot more work. First, we warn you that to conduct such experiments you must have very reliable wiring, otherwise disaster will not be avoided! So, what should you take into account? Tesla coils, as we already said, need really high voltage.

It must be at least 6 kV, otherwise you won’t see beautiful discharges, and the settings will constantly get lost. In addition, the spark plug should be made only from solid pieces of copper, and for the sake of your own safety, they should be fixed as firmly as possible in one position. The power of the entire “economy” should be at least 60 W, but it is better to take 100 or more. If this value is lower, then you will definitely not get a truly spectacular Tesla coil.

Very important! Both the capacitor and the primary winding must ultimately form a specific oscillatory circuit that enters into a state of resonance with the secondary winding.

Keep in mind that the winding can resonate in several different ranges at once. Experiments have shown that the frequency is 200, 400, 800 or 1200 kHz. As a rule, all this depends on the condition and location of the primary winding. If you don’t have one, you will have to experiment with the capacitance of the capacitor, and also change the number of turns on the winding.

We remind you once again that we are discussing a bifilar Tesla coil (with two coils). So the issue of winding should be approached seriously, because otherwise nothing meaningful will come of the idea.

Some information about capacitors

It is better to take the capacitor itself with a not too outstanding capacity (so that it has time to accumulate charge in time) or use a diode bridge designed for rectifying alternating current. Let us immediately note that the use of a bridge is more justified, since capacitors of almost any capacity can be used, but in this case you will have to take a special resistor to discharge the structure. It gives off a very (!) electric shock.

Note that we are not considering a Tesla coil on a transistor. After all, you simply won’t find transistors with the required characteristics.

Important!

In general, we remind you once again: before assembling the Tesla coil, check the condition of all wiring in the house or apartment, make sure there is a high-quality grounding! This may seem like a boring exhortation, but such tension is not to be trifled with!

It is imperative to very reliably isolate the windings from each other, since otherwise you will be guaranteed to break through. On the secondary winding, it is advisable to make insulation between the layers of turns, since any more or less deep scratch on the wire will be decorated with a small but extremely dangerous discharge corona. And now - let's get to work!

Let's get started

As you can see, you will not need so many elements for assembly. You just need to remember that for proper operation Devices must not only be assembled correctly, but also configured correctly! However, first things first.

Transformers (MOTs) can be removed from any old microwave oven. This is almost standard, but it has one important difference: its core almost always operates in saturation mode. Thus, a very compact and simple device can easily output up to 1.5 kV. Unfortunately, they also have specific disadvantages.

So, the magnitude of the current idle speed equal to approximately three to four amperes, and the heating even during idle time is very high. For an average microwave oven, the MOT produces about 2-2.3 kV, and is equal to approximately 500-850 mA.

Characteristics of ILOs

Attention! In these transformers, the primary winding starts at the bottom, while the secondary winding is located at the top. This design provides better insulation of all windings. As a rule, on the “secondary” there is a filament winding from the magnetron (approximately 3.6 Volts). Between the two layers of metal, an attentive craftsman may notice a couple of metal bridges. These are magnetic shunts. What are they for?

The fact is that they close on themselves some part of the magnetic field that the primary winding creates. This is done to stabilize the field and the current itself on the second winding. If they are not there, then at the slightest short circuit the entire load goes to the “primary”, and its resistance is very small. Thus, these small parts protect the transformer and you, as they prevent many unpleasant consequences. Oddly enough, is it still better to remove them? Why?

Remember that in microwave oven The problem of overheating of this important device is solved by installing powerful fans. If you have a transformer that does not have shunts, then its power and heat dissipation are much higher. In all imported microwave ovens, they are most often thoroughly filled epoxy resin. So why should they be removed? The fact is that in this case the current “drawdown” under load is significantly reduced, which is very important for our purposes. What to do with overheating? We recommend placing the ILO in

By the way, flat coil Tesla generally does without a ferromagnetic core and a transformer, but needs to supply a current of even greater voltage. Because of this, trying something similar at home is strongly discouraged.

Once again about safety precautions

A small addition: the voltage on the secondary winding is such that an electric shock if it breaks down will lead to guaranteed death. Remember that the Tesla coil circuit assumes a current strength of 500-850 A. The maximum value of this value, which still leaves a chance of survival, is... 10 A. So when working, do not forget for a second about the simplest precautions!

Where and for how much can I buy components?

Alas, there is some bad news: firstly, a decent ILO costs at least two thousand rubles. Secondly, finding it on the shelves of even specialized stores is almost impossible. There is only hope for collapses and “ flea markets”, through which you will have to run a lot in search of what you are looking for.

If possible, be sure to use the MOT from the old Soviet Electronika microwave oven. It is not as compact as imported analogues, but it operates in the mode of a regular transformer. Its industrial designation is TV-11-3-220-50. It has a power of approximately 1.5 kW, an output of about 2200 Volts, and a current strength of 800 mA. In short, the parameters are very decent even for our time. In addition, it has an additional 12V winding, ideal as a power source for the fan that will cool the Tesla spark plug.

What else should I use?

High-quality high-voltage ceramic capacitors of the K15U1, K15U2, TGK, KTK, K15-11, K15-14 series. They are difficult to find, so it is better to have good friends professional electricians. What about the high pass filter? You will need two coils that can reliably filter out high frequencies. Each of them must contain at least 140 turns of high-quality copper wire (varnished).

Some information about the spark generator

The spark generator is designed to excite oscillations in the circuit. If it is not in the circuit, then the power will flow, but the resonance will not. In addition, the power supply begins to “punch” through the primary winding, which is almost guaranteed to lead to short circuit! If the spark switch is not closed, the high voltage capacitors cannot charge. As soon as it closes, oscillations begin in the circuit. It is to prevent certain problems that throttles are used. When the spark plug closes, the inductor prevents current leakage from the power supply, and only then, when the circuit is open, accelerated charging of the capacitors begins.

Device characteristics

Finally, we will say a few more words about the Tesla transformer itself: for the primary winding you are unlikely to be able to find a copper wire required diameter, so it's easier to use copper tubes from refrigeration equipment. The number of turns is from seven to nine. At least 400 (up to 800) turns must be wound on the secondary. It is impossible to determine the exact amount, so experiments will have to be carried out. One output is connected to the TOP (lightning emitter), and the second is very (!) reliably grounded.

What is the emitter made of? Use an ordinary ventilation corrugation for this. Before you make a Tesla coil, a photo of which is here, be sure to think about how to design it more original. Below are some tips.

In conclusion...

Alas, this spectacular device has no practical application to this day. Some demonstrate experiments in institutes, others make money from this by arranging “miracles of electricity” parks. In America, a very wonderful friend a couple of years ago actually made a Christmas tree out of a Tesla coil...

To make her more beautiful, he applied various substances to the lightning emitter. Keep in mind: boric acid gives green, manganese makes the “Christmas tree” blue, and lithium gives it a crimson color. There are still debates about the true purpose of the invention of the brilliant scientist, but today it is a common attraction.

Here's how to make a Tesla coil.