Tesla coil operating frequency. DIY small Tesla coil

Tesla Coil consists of two coils L1 and L2, which sends a large pulse of current to coil L1. Tesla coils do not have a core. More than 10 turns are wound on the primary winding. The secondary winding is one thousand turns. A capacitor is also added to minimize spark discharge losses.

The Tesla coil produces a high transformation ratio. It exceeds the ratio of the number of turns of the second coil to the first. The output potential difference of a Tesla coil can be more than several million volts. This creates such discharges electric current that the effect is spectacular. The discharges can be several meters long.

Tesla coil principle

To understand how a Tesla coil works, you need to remember the rule in electronics: it is better to see once than to hear a hundred times. The Tesla coil circuit is simple. This simple Tesla coil device creates streamers.

A streamer flies out of the high-voltage end of a Tesla coil. purple. There is a strange field around it that causes a fluorescent lamp that is not connected and is in this field to glow.

A streamer is the energy loss in a Tesla coil. Nikola Tesla tried to get rid of streamers by connecting it to a capacitor. Without a capacitor there is no streamer, but the lamp burns brighter.

Tesla Coil can be called a toy, who shows interesting effect. She amazes people with her powerful sparks. Designing a transformer is an interesting business. One device combines different physics effects. People don't understand how a reel works.

A Tesla coil has two windings. The voltage is suitable for the first AC, creating a flow field. The energy goes to the second coil. The action of a transformer is similar.

The second coil and C s form oscillations that sum up the charge. The energy is held in the potential difference for some time. The more energy we put in, the output will have a greater potential difference.

The main properties of a Tesla coil:

Secondary circuit frequency.
Coefficient of both coils.
Good quality.

The coupling coefficient determines the speed of energy transfer from one winding to the secondary. The quality factor gives the time the circuit saves energy.

Similar to a swing

To better understand the accumulation of large potential differences in a circuit, imagine a swing being rocked by an operator. The same oscillation circuit, and the person serves as the primary coil. The swing stroke is the electric current in the second winding, and the rise is the potential difference.

The operator swings and transmits energy. Over several times they accelerated greatly and rose very high; they concentrated a lot of energy in themselves. The same effect occurs with a Tesla coil, an excess of energy occurs, a breakdown occurs and a beautiful streamer is visible.

You need to oscillate the swing in accordance with the beat. Resonance frequency is the number of oscillations per second.

The length of the swing trajectory is determined by the coupling coefficient. If you swing a swing, it will swing quickly and move away exactly the length of a person’s arm. This coefficient is one. In our case, a Tesla coil with an increased coefficient is the same.

A person pushes the swing, but does not hold it, then the coupling coefficient is small, the swing moves even further. It takes longer to swing them, but it doesn't require force. The coupling coefficient is greater the faster energy accumulates in the circuit. The potential difference at the output is less.

Quality factor is the opposite of friction, using the example of a swing. When friction is high, the quality factor is low. This means that the quality factor and coefficient are consistent for the highest swing height, or the largest streamer. In the transformer of the second winding of the Tesla coil, the quality factor is a variable value. It is difficult to reconcile the two values; it is selected as a result of experiments.

Main Tesla Coils

Tesla made one type of coil, with a spark gap. The base of elements has improved much, many types of coils have emerged, after which they are also called Tesla coils. Species are also called in English by abbreviations. They are called abbreviations in Russian, without translation.

A Tesla coil containing a spark gap. This is the initial conventional design. With low power it is two wires. WITH high power– arresters with rotation, complex. These transformers are good if you need a powerful streamer.
Transformer on a radio tube. It works smoothly and gives thicker streamers. Such coils are used for Tesla high frequency, they look like torches.
Coil on semiconductor devices. These are transistors. Transformers operate constantly. The type varies. This reel is easy to control.
There are two resonance coils. The keys are semiconductors. These coils are the most difficult to tune. The length of streamers is shorter than with a spark gap, they are less controlled.

To be able to control the view, a breaker was created. This device was used to slow down so that there was time to charge the capacitors and reduce the temperature of the terminal. This is how the length of the discharges was increased. Currently there are other options (music playing).

The main elements of a Tesla coil

In different designs, the main features and details are common.

Toroid– has 3 options. The first is reducing resonance.
The second is the accumulation of discharge energy. The larger the toroid, the more energy it contains. The toroid releases energy, increases it. This phenomenon will be beneficial if a breaker is used.
The third is the creation of a field with static electricity, repelling from the second winding of the coil. This option is performed by the second coil itself. The toroid helps her. Due to the field repulsion of the streamer, it does not hit the short path to the second winding. The use of a toroid benefits from pulse-pumped coils with interrupters. The outer diameter of the toroid is twice the size of the second winding.
Toroids can be made from corrugation and other materials.
Secondary coil– the basic component of Tesla.
The length is five times the diameter of the skein.
The diameter of the wire is calculated, 1000 turns fit on the second winding, the turns are wound tightly.
The coil is varnished to protect it from damage. Can be coated with a thin layer.
The frame is made from PVC sewer pipes, which are sold in construction stores.
Ring of Protection– serves to get the streamer into the first winding without damaging it. The ring is placed on a Tesla coil, the streamer is longer than the second winding. It looks like a coil of copper wire, thicker than the wire of the first winding, grounded by a cable to the ground.
Primary winding– created from a copper tube used in air conditioners. It has low resistance to high current I walked along it easily. The thickness of the pipe is not calculated, take approximately 5-6 mm. The wire for the primary winding is used with a large cross-sectional size.
The distance from the secondary winding is selected based on the availability of the required coupling coefficient.
The winding is adjustable when the first circuit is defined. Place, moving it adjusts the value of the primary frequency.
These windings are made in the form of a cylinder or cone.

Grounding- This is an important part.
The streamers hit the ground and short-circuit the current.
If there is insufficient grounding, the streamers will hit the coil.

The coils are connected to power through the ground.

There is an option to connect power from another transformer. This method is called "magnifer".

Bipolar Tesla coils produce a discharge between the ends of the secondary winding. This causes the current to close without grounding.

For a transformer, grounding is used as grounding with a large object that conducts electric current - this is a counterweight. There are few such structures, they are dangerous, since there is a high potential difference between the ground. The capacity from the counterweight and surrounding things negatively affects them.

This rule applies to secondary windings whose length is 5 times greater than their diameter, and with a power of up to 20 kVA.

How to make something spectacular using Tesla's inventions? Having seen his ideas and inventions, a Tesla coil will be made with his own hands.

This is a transformer that creates high voltage. You can touch the spark, light the light bulbs.

For production we need copper wire in enamel with a diameter of 0.15 mm. Anything from 0.1 to 0.3 mm will do. You need about two hundred meters. It can be obtained from various devices, for example, from transformers, or bought on the market, this will be better. You will also need several frames. Firstly, this is the frame for the secondary winding. Ideal option– this is a 5-meter sewer pipe, but anything with a diameter from 4 to 7 cm and a length of 15-30 cm will do.

For the primary coil you will need a frame a couple of centimeters larger than the first one. You will also need several radio components. This is a D13007 transistor, or its analogues, a small board, several resistors, 5.75 kilo-ohms 0.25 W.

We wind the wire onto the frame about 1000 turns without overlaps, without large gaps, carefully. Can be done in 2 hours. When the winding is finished, we coat the winding with several layers of varnish or other material so that it does not become unusable.

Let's wind the first coil. It hangs on the frame more and is wound with a wire of about 1 mm. A wire of about 10 turns is suitable here.

If you make a simple type transformer, then its composition is two coils without a core. On the first winding there are about ten turns of thick wire, on the second - at least a thousand turns. When manufactured, a do-it-yourself Tesla coil has a coefficient tens of times greater than the number of turns of the second and first windings.

The output voltage of the transformer will reach millions of volts. This gives a beautiful sight of several meters.

It is difficult to wind a Tesla coil with your own hands. It is even more difficult to create the appearance of a reel to attract viewers.

First you need to decide on a power supply of several kilovolts and attach it to a capacitor. If there is excess capacity, the value of the parameters of the diode bridge changes. Next, the spark gap is selected to create the effect.

The two wires are held together with the bare ends turned to the side.
The gap is set based on the penetration of a slightly higher voltage of a given potential difference. For alternating current, the potential difference will be above a certain level.
Connect power to the Tesla coil yourself.
The secondary winding of 200 turns is wound onto a pipe made of insulating material. If everything is done according to the rules, then the discharge will be good, with branches.
Grounding the second coil.

The result is a do-it-yourself Tesla coil, which you can make at home with basic knowledge of electricity.

Safety

The secondary winding is under voltage that can kill a person. The breakdown current reaches hundreds of amperes. A person can survive up to 10 amps, so don't forget about the bellows protection.

Tesla Coil Calculation

Without calculations, it is possible to make a transformer that is too large, but spark discharges greatly heat the air and create thunder. The electric field damages electrical appliances, so the transformer must be located further away.

To calculate the arc length and power, the distance between the electrode wires in cm is divided by 4.25, then squared, to obtain the power (W).

To determine the distance, the square root of the power is multiplied by 4.25. A winding that creates an arc discharge of 1.5 meters must receive a power of 1246 watts. A winding with a power supply of 1 kW creates a spark 1.37 m long.

Bifilar Tesla Coil

This method of wire winding distributes more capacitance than standard wire winding.

Such coils cause the turns to be closer together. The gradient is cone-shaped, not flat, in the middle of the coil, or with a dip.

The current capacity does not change. Due to the proximity of the sections, the potential difference between the turns increases during oscillations. Therefore, the capacitance resistance at high frequency decreases several times, and the capacity increases.

Write comments, additions to the article, maybe I missed something. Take a look at, I will be glad if you find anything else useful on mine.

One of Nikola Tesla's famous inventions was the Tesla Coil. This invention is a resonant transformer that produces high-frequency increased voltage. In 1896, a patent was issued for the invention, which was called an apparatus for generating electric current of high potential and frequency.

Design and operation

An elementary Tesla transformer includes two coils, a toroid, a capacitor, a spark gap, a protective ring and .

The toroid performs several functions:

Reducing the resonance frequency, especially for the type of Tesla coil with semiconductor switches. perform poorly at higher frequencies.
Accumulation of energy before the occurrence of an electric arc. The larger the toroid, the more energy is stored. At the moment of air breakdown, the toroid releases this accumulated energy into an electric arc, thereby increasing it.
The formation of an electrostatic field that repels the arc from the secondary winding. Part of this function is performed by the secondary winding. However, the toroid helps her with this. Therefore, the electric arc does not hit the secondary winding along the shortest path.

Typically the outer diameter of the toroid is twice the diameter of the secondary winding. Toroids are made from aluminum corrugation and other materials.

Secondary winding The Tesla transformer is the main design element. Typically, the length of the winding refers to its diameter 5:1. The diameter of the conductor for the coil is chosen to accommodate about 1000 turns, which should be located tightly together. The winding turns are coated with several layers of varnish or epoxy resin. PVC pipes, which can be purchased at a hardware store, are chosen as the frame.

Protective ring serves to protect against failure of electronic elements in the event of an electric arc entering the primary winding. A protective ring is installed if the size of the streamer (electric arc) is greater than the length of the secondary coil. This ring is made in the form of an open copper conductor, grounded by a separate wire to a common ground.

Primary winding most often made from copper tube, used in air conditioners. The resistance of the primary winding should be small, since a large current will pass through it. The tube most often chosen is 6 mm thick. Large cross-section conductors can also be used for winding. The primary winding is a kind of tuning element in Tesla coils in which the first circuit is resonant. Therefore, the location of the power connection is made taking into account its movement, with the help of which the resonance frequency of the primary circuit is changed.

The shape of the primary winding can be different: conical, flat or cylindrical.

The Tesla coil must have grounding. If it is not there, then the streamers will hit the coil itself to close the current.

The oscillatory circuit is formed by a capacitor together with the primary winding. A spark gap is also connected to this circuit, which is nonlinear element. An oscillation circuit is also formed in the secondary winding, in which the capacitance of the toroid and the interturn capacitance of the coil act as a capacitor. Most often, to protect against electrical breakdown, the secondary winding is coated with varnish or epoxy resin.

As a result, a Tesla coil, or in other words a transformer, consists of two oscillation circuits connected to each other. This gives the Tesla transformer unusual properties, and is the main distinguishing quality from conventional transformers.

When the breakdown voltage is reached between the electrodes of the spark gap, an electrical avalanche-like breakdown of the gas is formed. In this case, the capacitor is discharged onto the coil through a spark gap. As a result, the circuit of the oscillation circuit, which consists of a capacitor and the primary winding, remains closed to the spark gap. High frequency oscillations occur in this circuit. Resonant oscillations are formed in the secondary circuit, resulting in high voltage.

In all types of Tesla coils, the main element is the circuits: primary and secondary. However, the high frequency oscillator may differ in design.

A Tesla coil essentially consists of two coils that do not have a metal core. The transformation coefficient of a Tesla coil is several tens of times higher than the ratio of the number of turns of both windings. Therefore, the output voltage of the transformer reaches several million volts, which provides powerful electrical discharges several meters long. An important condition is the formation of an oscillation circuit by the primary winding and a capacitor, and the resonance of this circuit with the secondary winding.

Varieties

Since the time of Nikola Tesla, many various types Tesla transformers. Let's consider the common main types of transformers such as the Tesla coil.

SGTC– the coil operating on a spark discharge has a classic device used by Tesla himself. In this design, the switching element is a spark gap. For low-power devices, the arrester is made in the form of two sections of thick conductor located at a certain distance. Higher power devices use rotating arresters of complex design using electric motors. Such transformers are produced when it is necessary to obtain a streamer of great length, without any effects.

VTTC– a coil based on an electron tube, which is a switching element. Such transformers are capable of operating in constant mode and produce discharges of great thickness. This type of power supply is usually used to create high frequency coils. They create a streamer effect in the form of a torch.

SSTC- a coil in the design of which a semiconductor element in the form of a powerful one is used as a key. This type of transformer is also capable of operating in continuous mode. External form streamers from such a device can be very different. Control with a semiconductor key is simpler; there are Tesla coils that can play music.

DRSSTC– a transformer having two resonance circuits. Semiconductor components also play the role of keys. This is the most difficult transformer to set up and control, however, it is used to create impressive effects. In this case, a large resonance is obtained in the primary circuit. In the second circuit, the brightest thick and long streamers in the form of lightning are formed.

Types of effects from a Tesla coil

Arc discharge – occurs in many cases. It is typical for tube transformers.
Corona discharge is the glow of air ions in an electric field high voltage, forms a beautiful bluish glow around the elements of the device with high voltage, and also having a large surface curvature.
Spark otherwise called spark discharge. It flows from the terminal to the ground, or to a grounded object, in the form of a bunch of bright branched stripes that quickly disappear or change.
Streamers – these are thin, weakly luminous branching channels containing ionized gas atoms and free electrons. They do not go into the ground, but flow into the air. A streamer is the ionization of air generated by the field of a high voltage transformer.

The action of a Tesla coil is accompanied by a crackling sound of electric current. Streamers can turn into spark channels. This is accompanied by high magnification current and energy. The streamer channel rapidly expands, the pressure rises sharply, and therefore a shock wave is formed. The combination of such waves is like the crackle of sparks.

Little-Known Effects of the Tesla Coil

Some people consider the Tesla transformer to be some special device with exceptional properties. There is also an opinion that such a device can become an energy generator and perpetual motion machine.

Sometimes they say that with the help of such a transformer it is possible to transmit electrical energy over significant distances without using wires, and also create anti-gravity. Such properties have not been confirmed or tested by science, but Tesla spoke about the imminent availability of such abilities for humans.

In medicine, prolonged exposure to high-frequency currents and voltages can lead to chronic diseases and other negative phenomena. Also, a person’s presence in a high voltage field negatively affects his health. You can be poisoned by the gases released when the transformer operates without ventilation.

Application

The voltage at the output of a Tesla coil sometimes reaches millions of volts, which forms significant airborne electrical discharges several meters long. Therefore, such effects are used to create demonstration shows.
The Tesla coil found application in medicine at the beginning of the last century. The patients were treated with low-power, high-frequency currents. Such currents flow across the surface of the skin, have a healing and tonic effect, without causing any harm to the human body. However, powerful high frequency currents have a negative effect.
The Tesla coil is used in military equipment for the rapid destruction of electronic equipment in a building, on a ship, or in a tank. In this case, a powerful pulse of electromagnetic waves is created for a short period of time. As a result, transistors, microcircuits and other devices burn out within a radius of several tens of meters. electronic components. This device operates absolutely silently. There is evidence that the current frequency during operation of such a device can reach 1 THz.
Sometimes such a transformer is used for ignition gas discharge lamps, as well as searching for leaks in a vacuum.

Tesla coil effects are sometimes used in filming, computer games. Currently, the Tesla coil has not found widespread practical use in everyday life.

Tesla coil on future

Currently remain topical issues, which was studied by the scientist Tesla. Consideration of these problematic issues allows students and engineers of institutes to look at scientific problems more broadly, structure and generalize the material, and abandon stereotyped thoughts.

Tesla's views are relevant today not only in technology and science, but also for work on new inventions and the use of new technologies in production. Our future will provide an explanation for the phenomena and effects discovered by Tesla. He laid the foundations of modern civilization for the third millennium.

Nikola Tesla, is a coil or resonant transformer capable of delivering high voltage at high frequency. In order to imagine the operation of this device, you need to know the principle of operation of the Tesla coil.

Tesla transformer: principle of operation

Operating principle of this device comparable to the action of a regular swing. In forced swing mode, the maximum amplitude is in proportion to the applied effort. If the swing is performed in a free mode, an even greater increase in the maximum amplitude occurs.

In the coil, the swing is the secondary oscillation circuit, and the applied force is provided by the generator. They operate at a strictly designated time.

Tesla coil design

The simplest transformer has two coils - primary and secondary. In addition, the design includes a spark gap, a capacitor and a terminal. Ultimately, two oscillation circuits are formed, interconnected. This is the main difference between a Tesla coil and a conventional transformer.

In order for the coil to work fully, both oscillation circuits are tuned to the same resonance frequency. The adjustment is made by adjusting the primary circuit to the secondary circuit, changing the capacitance of the capacitor and the number of turns. As a result, maximum voltage is generated at the output of the coil.

To operate the Tesla transformer, a pulse mode is used. At the first stage, the amount of charge on the capacitor should be equal to the voltage causing the breakdown of the spark gap. In the second stage, high frequency oscillations are generated in the primary circuit. At the same time, a spark gap is switched on, closing the transformer and removing it from the general circuit. Otherwise, losses may occur in the primary circuit, which may affect its performance. In a normal circuit, the arrester is usually installed in parallel with the power source.

Thus, the voltage value at the output of a Tesla coil can be several million volts. With the help of such tension, in, reaching a considerable length. Their appearance literally mesmerizes, and in many cases the transformer is used as a decorative item.

The principle of operation of the Tesla coil helps to find practical application this device. As a rule, it is assigned a cognitive and aesthetic role. This is due to certain difficulties in controlling the device and transmitting the data received over a distance.

Every person has most likely heard about what a Tesla transformer is, which is also often called a Tesla coil. This reel can be seen in many films, computer games and television programs. However, it is not enough to hear that something like this exists. If you are asked what exactly a Tesla transformer does, can you answer that question? Most likely not, and even if you can, you are unlikely to be able to provide enough details. That is why this article exists. With its help, you can learn everything about the Tesla transformer, how it works, what it is used for, how it functions, and so on. Naturally, if you studied physics, then this data will not be news to you, but most people are still not aware of the details regarding the Tesla coil. But this is very interesting data that will allow you to broaden your horizons. As you can easily guess, the inventor of this device was the great scientist Nikola Tesla, who patented his invention in 1896, describing it as a device designed to produce high-frequency electrical currents. Essentially, this is what a Tesla coil is, and you most likely already knew about it. So it's worth taking a look at more interesting and lesser-known data.

What's the point?

First, we need to explain the essence of how a Tesla coil works. She may look different, but many people note that, one way or another, she looks very impressive even in calm mode. What can we say about when it is activated, and visible discharges of electricity are formed around it. But how exactly does this happen? The Tesla transformer operates due to resonant electromagnetic waves generated in two windings of the coil, primary and secondary. The primary winding is part of the spark oscillatory center. As for the secondary, its role is played by a straight coil of wire. When the oscillation frequency of the primary and secondary circuits coincides, a high voltage appears between the ends of the coil. alternating voltage, which you can see with the naked eye. If you don’t really understand how the Tesla transformer works, then you can take an ordinary swing as an example. With their help, it will be much easier to explain the work. If you swing a swing using forced vibrations, then the amplitude will be proportional to your effort. If you decide to swing the swing in free oscillation mode, each time pushing the swing at the right moment, the amplitude will increase several times. The same thing happens with a Tesla coil: when the oscillations of the two windings resonate, a much stronger current arises.

Transformer design

The second point to consider when considering a Tesla transformer is the circuit. How exactly is the coil constructed? In fact, the design of this transformer can be very diverse, so now you will learn about how it works simplest version, which you can then improve the way you want. So, the simplest Tesla transformer consists of several elements, namely an input transformer, an inductor, which includes a primary and secondary winding, as well as a spark gap, a capacitor and a terminal. Strictly speaking, the current begins its movement from the input transformer, which is the power source, from where it reaches the inductor through a spark gap and a capacitor, and from there it is transmitted to the terminal in a multiplied amount. Moreover, the terminal is often chosen so that it can best transmit such voltage, for example, it can be in the shape of a ball or disk. As you understand, this is the simplest Tesla transformer - the diagram is proof of this. There can be more elements in a Tesla coil. There may be, for example, a toroid, which is not described in this diagram, since it is not key element. As for the main elements, they were all indicated.

Operation

So, now you know how the Tesla transformer works. The principle of its operation is also clear to you in general, but you can go deeper into the details. How exactly does it function? It turns out that it works in pulse mode. What does this mean? This means that the capacitor is first charged until the spark gap breaks down and electricity passes to the inductor. Then the second phase begins, during which high-frequency oscillations are generated. Note that the spark gap must be parallel to the power source, causing it to complete the circuit when current is applied to the coil, thereby removing the power source from the circuit. Why is this necessary? If left as part of a circuit, it can significantly reduce the voltage output from the transformer. Naturally, the result will still be there, but it will be far from the most impressive. This is how the Tesla transformer functions. The principle of operation is now completely clear to you, but there are still some details that may interest you.

Charge for transformer

As you may have already noticed, if you are planning to create a powerful Tesla transformer, then absolutely every detail will need to be taken into account, since any deviations from the norm will lead to the output voltage not being high enough, which is why the effect will be less impressive. And special attention must be paid to the starting charge, that is, the selection of a power source. It is in in this case you need to choose the right capacitor so that the output voltage is ideal and the capacitor does not “short-circuit” itself. There is even a self-powered Tesla transformer, so there are no limits to the variety of designs. So you should remember that in this case we are considering the simplest Tesla coil design.

Generation

Well, the last thing that is worth looking at in more detail is the process of generating high-frequency current itself. So, the Tesla transformer is powered by the selected power source, which transfers the charge to the capacitor, where it accumulates until a breakdown occurs, as a result of which the capacitor is discharged through the spark gap to the primary coil. Since the voltage of the spark gap decreases sharply, the circuit is closed, and, as mentioned above, the power source is excluded from the circuit. At this time, high-frequency oscillations occur in the primary coil, which are then transmitted to the secondary coil, due to which the oscillations become resonant and a high voltage current is generated at the terminal. This is how the simplest Tesla transformer works, but there is large number its widest variety of modifications.

Modifications

First, you should know that the classic version of the Tesla coil, which was described above, is designated as follows - SGTC. The last two letters stand for Tesla Coil, which translates directly as “Tesla coil”. These two letters will be present in each of the abbreviations, and only the first two change. In this case, SG stands for Spark Gap, meaning this Tesla coil operates on the spark gap created by the spark gap. However, this is not always the case, so it is necessary to consider various options, such as a Tesla transformer based on transistors or semiconductors. The first modification that you can pay attention to is RSGTC, that is, a coil that operates on a rotary spark gap. In this case, an electric motor is used for power, which rotates a disk with electrodes. There is also VTTC which is known as Tesla Tube Coil which works by vacuum tubes. This option does not require high voltage and is also quiet. The next option is SSTC, that is, a Tesla coil, which is powered by a semiconductor-based generator. This modification is one of the most interesting in terms of effectiveness, since with the help of power switches you can change the shape of the discharge. A modification of this version of the Tesla coil is DRSSTC. In this case, double resonance is used, which gives a much more impressive discharge size. Separately, it’s worth taking a look at the QCW DRSSTC - this Tesla coil is characterized by “smooth pumping,” that is, a smooth rather than sharp increase in all parameters. In each of these cases, the calculation of the Tesla transformer will be different, just like its designs and, accordingly, its circuit.

Using a Tesla Coil

But how can the energy of a Tesla transformer be used? This question is asked by every person who sees the operation of this device for the first time. As a matter of fact, admiring the incredible discharges, which are huge in size and look very impressive, is one of the most important and popular uses. This transformer allows you to put on a real show that can charm any person, because this is not magic, but pure science. So we can safely say that one of the main roles of the Tesla transformer is decoration and entertainment. However, it turns out that there are other ways to use this technology. For example, Tesla coils were originally used for radio control, wireless transmission data and for energy transfer. Naturally, over time, more effective ways perform each of these functions, so gradually the use of a Tesla coil became less and less relevant. It is also worth noting that it was used in medicine. The fact is that the high-frequency discharge, when passed over the skin, did not have any effect negative influence on the internal organs of a person, but at the same time toned the human skin. IN modern world The Tesla coil is no longer actually used from a practical point of view due to the difficulties of maintaining its constant operation. It is sometimes used to ignite gas discharge lamps or in vacuum systems where the transformer helps find leaks. Thus, the use of the Tesla transformer in the modern world is still, in most cases, decorative, entertaining and educational.

Effects

You already imagine the design of the Tesla transformer, so there is no point in saying anything else on this topic. However, this does not mean that the topic of the Tesla coil itself has exhausted itself. For example, you can look at exactly what discharges are created as a result of its activities. It turns out that they are not random: in total there are four main types. First, you can see streamers, which are dim, branching channels that extend away from the terminal into the air. Essentially, they are a visualization of air ionization. Secondly, you may notice sparks - these are spark discharges that go from the terminal directly into the ground. They can be distinguished due to the fact that they stand out very strongly in appearance - they are a bunch of bright spark channels. Thirdly, there is a corona discharge - this is the name given to the glow of ions directly in a high voltage field. And, finally, there is also an arc discharge, which occurs if any grounded object is brought to the transformer. This technique is used by many when the Tesla coil is used for entertainment purposes.

Health effects

It was stated above that after the invention of the Tesla coil, it was used for medical purposes, but many sources report that the Tesla transformer is deadly. Who is right and who is deceiving? In most cases, high voltage is fatal to humans, as it leads to burns and cardiac arrest. However, some types of Tesla transformers have the so-called skin effect, which allows electricity to affect only the surface of an object, and in this case, human skin. As mentioned above, this tones the skin and rejuvenates it. Again, there is no medical evidence of this fact, but a lot was written about this at one time.

Tesla coil as part of culture

Even if you're not into science, you've probably already seen a Tesla coil, as it's used in a wide variety of entertainment applications. First of all, she can be seen in many films that were released on cinema screens in various years. One of the most famous films in which very important role played the Tesla transformer, became a film adaptation of the novel of the same name “Prestige”. Also, very often the Tesla coil can be found in computer games, where it most often acts as a powerful weapon. Moreover, you can find Tesla transformers even in musical art. It turns out that you can change the sound of an electrical discharge by increasing and decreasing the frequency of the current. And some performers and musical groups use it to record music. And those who do not want to complicate everything resort to the help of a Tesla coil to create realistic sounds of lightning discharges, as, for example, the famous singer Björk did. Thus, in the modern world, Tesla transformers are used very widely, but it cannot be said that they are used for their intended purpose. Your time as functional device The Tesla coil has already become obsolete, and it, in fact, should have sunk into oblivion, like most old devices. However, thanks visual effects, which she creates, the Tesla coil was able to survive to this day, and it continues to be used constantly, albeit as an item of entertainment. It is also worth noting that it is also used for educational purposes, since it is on it that one can clearly demonstrate to novice physicists what an electric discharge looks like, how it behaves, and so on. Simply put, the Tesla transformer is a device that has existed for a hundred years and has not lost its relevance even in the twenty-first century, which is known to everyone for its incredible progress in the field of high technology.

In 1997, I became interested in the Tesla coil and decided to build my own. Unfortunately, I lost interest in it before I could launch it. A few years later I found my old spool, re-counted it a bit and continued building. And again I abandoned her. In 2007, a friend showed me his reel, reminding me of my unfinished projects. I found my old spool again, counted everything and this time completed the project.

Tesla Coil- This is a resonant transformer. These are basically LC circuits tuned to one resonant frequency.

A high voltage transformer is used to charge the capacitor.

As soon as the capacitor reaches a sufficient charge level, it is discharged into the spark gap and a spark occurs there. Happening short circuit primary winding of the transformer and oscillations begin in it.

Since the capacitance of the capacitor is fixed, the circuit is adjusted by changing the resistance of the primary winding, changing the point of connection to it. At correct setting, very high voltage will be at the top of the secondary winding, resulting in impressive discharges in the air. Unlike traditional transformers, the turns ratio between the primary and secondary windings has little effect on the voltage.

Construction stages

Designing and building a Tesla coil is quite easy. This seems like a difficult task for a beginner (I found it difficult too), but you can get a working coil by following the instructions in this article and doing a little math. Of course, if you want a very powerful coil, there is no way other than studying the theory and doing a lot of calculations.

Here are the basic steps to get started:

Selecting a power source. The transformers used in neon signs are probably best for beginners since they are relatively cheap. I recommend transformers with an output voltage of at least 4 kV.
Making a spark gap. It could be as simple as two screws a couple of millimeters apart, but I recommend using a little more force. The quality of the arrester greatly influences the performance of the coil.
Calculation of capacitor capacity. Using the formula below, calculate the resonant capacitance for the transformer. The capacitor value should be about 1.5 times this value. Probably the best and most effective solution There will be an assembly of capacitors. If you don't want to spend money, you can try making a capacitor yourself, but it may not work and its capacity is difficult to determine.
Manufacturing of the secondary winding. Use 900-1000 turns of enamel copper wire 0.3-0.6mm. The height of the coil is usually equal to 5 times its diameter. PVC drainpipe may not be the best but affordable material for a reel. A hollow metal ball is attached to the top of the secondary winding, and its bottom is grounded. For this, it is advisable to use a separate grounding, because When using common house grounding, there is a chance of damaging other electrical appliances.
Manufacturing of the primary winding. The primary winding can be made of thick cable, or better yet, copper tubing. The thicker the tube, the less resistive losses. A 6mm tube is sufficient for most reels. Remember that thick pipes are much more difficult to bend and copper will crack if it is bent too many times. Depending on the size of the secondary winding, 5 to 15 turns at 3 to 5 mm pitches should be sufficient.
Connect all the components, set up the coil, and you're done!

Before you start making a Tesla coil, it is strongly recommended that you familiarize yourself with the safety rules and working with high voltages!

Also note that transformer protection circuits were not mentioned. They have not been used and there are no problems so far. Keyword here - for now.

Details

The coil was made mainly from those parts that were available.
These were:
4kV 35mA transformer from neon sign.
0.3mm copper wire.
0.33μF 275V capacitors.
I had to buy an additional 75mm PVC drain pipe and 5 meters of 6mm copper pipe.

Secondary winding

The secondary winding is covered with plastic insulation on top and bottom to prevent breakdown

The secondary winding was the first component manufactured. I wound about 900 turns of wire around a drain pipe that was about 37cm high. The length of the wire used was approximately 209 meters.

The inductance and capacitance of the secondary winding and the metal sphere (or toroid) can be calculated using formulas that can be found on other sites. Having these data, you can calculate the resonant frequency of the secondary winding:
L = [(2πf) 2 C] -1

When using a sphere with a diameter of 14 cm, the resonant frequency of the coil is approximately 452 kHz.

Metal sphere or toroid

The first attempt was to make a metal sphere by wrapping a plastic ball in foil. I couldn't smooth out the foil on the ball well enough, so I decided to make a toroid. I made a small toroid by wrapping aluminum tape around a corrugated pipe rolled into a circle. I couldn't get a very smooth toroid, but it works better than a sphere because of its shape and due to larger size. To support the toroid, a plywood disk was placed under it.

Primary winding

The primary winding consists of copper tubes with a diameter of 6 mm, wound in a spiral around the secondary. The inner diameter of the winding is 17cm, the outer diameter is 29cm. The primary winding contains 6 turns with a distance of 3 mm between them. Due to the large distance between the primary and secondary windings, they may be loosely coupled.
The primary winding together with the capacitor is an LC oscillator. The required inductance can be calculated using the following formula:
L = [(2πf) 2 C] -1
C is the capacitance of the capacitors, F is the resonant frequency of the secondary winding.

But this formula and calculators based on it give only an approximate value. Correct size The coil must be selected experimentally, so it is better to make it too large than too small. My coil consists of 6 turns and is connected on the 4th turn.

Capacitors

Assembly of 24 capacitors with a 10 MΩ quenching resistor on each

Since I had a large number of small capacitors, I decided to collect them into one large one. The value of capacitors can be calculated using the following formula:
C = I ⁄ (2πfU)

The capacitor value for my transformer is 27.8 nF. The actual value should be slightly more or less than this, since the rapid rise in voltage due to resonance can damage the transformer and/or capacitors. Quenching resistors provide some protection against this.

My capacitor assembly consists of three assemblies with 24 capacitors each. The voltage in each assembly is 6600 V, total capacity all assemblies 41.3nF.

Each capacitor has its own 10 MΩ quenching resistor. This is important because individual capacitors can retain a charge for a very long time after the power has been turned off. As you can see from the figure below, the capacitor voltage rating is too low, even for a 4kV transformer. To work well and safely it must be at least 8 or 12 kV.

Arrester

My arrester is just two screws with a metal ball in the middle.
The distance is adjusted so that the arrester will spark only when it is the only one connected to the transformer. Increasing the distance between them can theoretically increase the spark length, but there is a risk of destroying the transformer. For a larger coil it is necessary to build an air-cooled arrester.