Tesla coil diagrams and description. The main properties of the Tesla coil

Clone PI-W and, now, it came to making a mono search coil. And since I am currently experiencing some financial difficulties, I was faced with a difficult task - to make a reel myself from the cheapest materials possible.

Looking ahead, I’ll say right away that I coped with the task. As a result, I got this sensor:

By the way, the resulting ring coil is perfect not only for Clone, but also for almost any other impulse generator (Koschei, Tracker, Pirate).

I will tell you in great detail, since the devil is often in the details. Moreover, short stories making coils is a dime a dozen on the Internet (like, we take this, then we cut it off, wrap it, glue it together and you’re done!) But you start doing it yourself and it turns out that the most important thing was mentioned in passing, and something else was completely forgotten to be said... And it turns out that that everything is more complicated than it seemed at the very beginning.

This won't happen here. Ready? Go!

Idea

Easiest for self-made I thought this design: take a disk from sheet material thickness ~4-6 mm. The diameter of this disk is determined by the diameter of the future winding (in my case it should be 21 cm).

Then we glue two disks of slightly larger diameter to this pancake on both sides to make a bobbin for winding wire. Those. such a coil greatly increased in diameter, but flattened in height.

For clarity, I’ll try to depict this in a drawing:

I hope the main idea is clear. Just three disks glued together over the entire area.

Material selection

I planned to use plexiglass as the material. It is perfectly processed and glued with dichloroethane. But, unfortunately, I couldn’t find it for free.

All sorts of collective farm materials such as plywood, cardboard, bucket lids, etc. I immediately discarded them as unsuitable. I wanted something strong, durable and preferably waterproof.

And then my gaze turned to fiberglass...

It's no secret that fiberglass (or glass mat, fiberglass) can be used to make whatever your heart desires. Even motor boats and bumpers for cars. The fabric is impregnated with epoxy resin, given the desired shape and left until completely cured. The result is a durable, water-resistant, easy-to-handle material. And this is exactly what we need.

So, we need to make three pancakes and ears for attaching the barbell.

Manufacturing of individual parts

Pancakes No. 1 and No. 2

Calculations showed that to obtain a sheet 5.5 mm thick, you need to take 18 layers of fiberglass. To reduce epoxy consumption, it is better to pre-cut the fiberglass into circles of the required diameter.

For a disc with a diameter of 21 cm, 100 ml was just enough epoxy resin.

Each layer must be thoroughly coated, and then the entire stack must be placed under the press. The greater the pressure, the better - the excess resin will be squeezed out, the mass of the final product will become a little less, and the strength will be a little greater. I loaded about a hundred kilograms on top and left it until the morning. The next day I ended up with this pancake:

This is the most massive part of the future coil. He weighs - be healthy!

Then I’ll tell you how using this spare part it will be possible to significantly reduce the weight of the finished sensor.

A disk with a diameter of 23 cm and a thickness of 1.5 mm was made in exactly the same way. Its weight is 89 g.

Pancake #3

There was no need to glue the third disk. I had a sheet of fiberglass at my disposal. suitable size and thickness. It was printed circuit board from some ancient device:

Unfortunately, the board had metallized holes, so I had to spend some time drilling them.

I decided that this would be the top disk, so I made a hole in it for the cable entry.

Ears for barbell

There was just enough leftover textolite for the ears to attach the sensor housing to the rod. I cut out two pieces for each ear (to make it durable!)

In the ears, you must immediately drill holes for plastic bolt, since it will be very inconvenient to do this later.

By the way, this is a mounting bolt for the toilet seat.

So, all the components of our coil are ready. All that remains is to glue it all together into one big sandwich. And don't forget to run the cable inside.

Assembly into one piece

First, the upper disk made of holey fiberglass was glued to the middle pancake made of 18 layers of fiberglass. This took literally a few milliliters of epoxy - this was enough to coat both surfaces to be glued over the entire area.

Ear mounting

I cut the grooves using a jigsaw. Naturally, I overdid it a little in one place:

To make the ears fit well, I made a small bevel on the edges of the cuts:

Now we had to decide which option is better? Ears can be placed in different ways...

Reels industrial production Most often they are made according to the right version, but I like the left one better. In general, I often make leftist decisions...

In theory, the right method is better balanced, because The rod mount is closer to the center of gravity. But it is far from a fact that after lightening the coil, its center of gravity will not shift in one direction or another.

The left mounting method looks more visually pleasing (IMHO), and in this case the total length of the metal detector when folded will be a couple of centimeters shorter. For someone who plans to carry the device in a backpack, this may be important.

In general, I made my choice and started gluing. He generously smeared it with bauxite, securely fixed it in the desired position and left it to harden:

After hardening, everything sticking out from reverse side sanded it off with sandpaper:

Cable entry

Then, using a round file, I prepared grooves for the conductors, inserted the connecting cable through the hole and glued it tightly:

To prevent strong kinks, the cable at the entry point needed to be somehow reinforced. For these purposes, I used this little rubber thing that I got from God knows where:

All that remained was to glue the third pancake (the bottom).

Finishing the frame

To glue the third pancake it took several milliliters of bauxite and a couple of hours for everything to set. Here is the result:
Thus, I received a rigid and durable frame, fully prepared for winding the wire.

Winding sealing

An enameled copper wire with a diameter of 0.71 mm was used as a winding wire. After winding 27 turns, the sensor became heavier by another 65 grams:

Now the winding had to be caulked somehow. As putty I used a mixture of epoxy resin and finely chopped fiberglass (I learned about this super recipe from).

In short, I cut some fiberglass:

and mixed it thoroughly with bauxite with the addition of paste from ballpoint pen. The result was a viscous substance similar to wet hair. With this composition you can cover any cracks without problems:

Pieces of fiberglass give the putty the necessary viscosity, and after hardening, provide increased strength to the adhesive joint.

So that the mixture is properly compacted, and the resin saturates the turns of the wire, I wrap it all with electrical tape tightly:

The electrical tape must be green or, at worst, blue.

After everything froze thoroughly, I wondered how strong the structure turned out to be. It turned out that the reel could easily support my weight (about 80 kg).

In fact, we don’t need such a heavy-duty reel; its weight is much more important. Too much mass of the sensor will definitely cause shoulder pain, especially if you plan to conduct a long search.

Facilitating

To reduce the weight of the coil, it was decided to cut out some sections of the structure:

This manipulation allowed me to lose 168 grams excess weight. At the same time, the strength of the sensor has practically not decreased, as can be seen in this video:

Now, with hindsight, I understand how the coil could have been made a little lighter. To do this, it was necessary to do this in advance large holes in a medium pancake (before gluing everything together). Something like this:

The voids inside the structure would have almost no effect on the strength, but would reduce the total mass by another 20-30 grams. Now, of course, it’s too late to rush around, but I’ll keep it in mind for the future.

Another way to simplify the design of the sensor is to reduce the width of the outer ring (where the wire turns are laid) by 6-7 millimeters. Of course, this can be done now, but there is no such need yet.

Finish painting

I found an excellent paint for fiberglass and fiberglass products - epoxy resin with the addition of dye desired color. Since the entire structure of my sensor is made on the basis of bauxite, the resin-based paint will have excellent adhesion and will fit like original.

Used as a black dye alkyd enamel PF-115, adding it until the desired coverage is obtained.

As practice has shown, a layer of such paint holds very firmly, and looks as if the product was dipped in liquid plastic:

In this case, the color can be any depending on the enamel used.

The final weight of the search coil together with the cable after painting is 407 g

The cable separately weighs ~80 grams.

Examination

After our homemade reel was completely ready for the metal detector, it was necessary to check it for the absence of an internal break. The easiest way to check is to use a tester to measure the winding resistance, which normally should be very low (maximum 2.5 Ohms).

In my case, the resistance of the coil together with two meters of connecting cable turned out to be around 0.9 Ohm.

Unfortunately, this in a simple way It will not be possible to detect an interturn short circuit, so you have to rely on your accuracy when winding. A short circuit, if there is one, will immediately manifest itself after starting the circuit - the metal detector will consume increased current and have extremely low sensitivity.

Conclusion

So, I think that the task was completed successfully: I managed to make a very durable, waterproof and not too heavy reel from the most waste materials. List of expenses:

• Fiberglass sheet 27 x 25 cm - free;
• Sheet of fiberglass, 2 x 0.7 m - free;
• Epoxy resin, 200 g - 120 rubles;
• Enamel PF-115, black, 0.4 kg - 72 RUR;
• Winding wire PETV-2 0.71 mm, 100 g - 250 rub;
• Connecting cable PVS 2x1.5 (2 meters) - 46 rubles;
• Cable entry is free.

Now I am faced with the task of making exactly the same rogue barbell. But that's already it.

In this article I will talk about the Tesla transformer device I assembled and the interesting effects that were observed in it during its operation.

I would like to straight away dot the i’s, this device works with high voltages, so compliance with basic safety rules is MANDATORY! Failure to follow the rules will result in serious injury, remember this! I would also like to note that the main danger in this device is the ISKROVIK (discharge arrester), which during its operation is a source of wide-spectrum radiation, including X-rays, remember this!

Let's begin. I’ll tell you briefly about the design of “my” Tesla transformer, in common parlance “Tesla coil”. This device is made on a simple element base, accessible to everyone. The block diagram of the device is shown below.

As you can see, I did not reinvent the wheel and decided to stick to the classic Tesla transformer circuit, the only thing added to the classic circuit is an electronic voltage converter - the role of which is to increase the voltage from 12 Volts to 10 thousand volts! By the way, this voltage converter can be assembled by a housewife. In the high-voltage part of the circuit, the following elements are used: The VD diode is a high-voltage 5GE200AF diode - it has high resistance - this is very important! Capacitors C1 and C2 have a nominal value of 2200 pF, each designed for a voltage of 5 kV. As a result, we get a total capacitance of 1100 pF and an accumulated voltage of 10 kV, which is very good for us! I would like to note that the capacitance is selected experimentally; the duration of the pulse in the primary coil depends on it, and of course on the coil itself. The pulse time must be less than the lifetime of electron pairs in the conductor of the primary coil of the Tesla transformer, otherwise we will have a low effect and the pulse energy will be spent on heating the coil - which we do not need! Shown below assembled structure devices.

The design of the spark gap deserves special attention; most modern Tesla transformer circuits have a special spark generator design driven by an electric motor, where the discharge frequency is regulated by the rotation speed, but I decided not to follow this trend, since there are many negative points. I went along classic scheme arrester. The technical drawing of the arrester is given below.

Cheap and practical option It doesn’t make noise or light up, I’ll explain why. This arrester is made of copper plates 2-3 mm thick with dimensions 30x30 mm (to act as a radiator, since the arc is a heat source) with threads for bolts in each plate. To prevent the bolt from unwinding during discharge and to ensure good contact, it is necessary to use a spring between the bolt and the plate. To dampen the noise during a discharge, we will make a special chamber where the arc will burn, my chamber is made from a piece of polyethylene water pipe (which does not contain reinforcement), the piece of pipe is clamped tightly between two plates and it is advisable to use sealing, for example, I have a special double-sided tape for insulation . The gap is adjusted by screwing in and unscrewing the bolt; I’ll explain why later.

Primary coil of the device. The primary coil of the device is made and copper wire type PV 2.5mm.kv and here the question arises: “What is such a thick wire for?” I'll explain. The Tesla transformer is a special device, one might say anomalous, which is not of the same type as ordinary transformers, where the laws are completely different. For a conventional power transformer important its operation is self-induction (counter-EMF) which compensates for part of the current; when a conventional power transformer is loaded, the counter-EMF decreases and the current increases accordingly; if we remove the counter-EMF from conventional transformers, they will flare up like candles. But in the Tesla transformer it’s the other way around - self-induction is our enemy! Therefore, to combat this disease, we use a thick wire that has low inductance, and therefore low self-inductance. We need powerful electromagnetic pulse and we get it using this type of coil. The primary coil is made in the form of an Archimedes spiral in one plane in the amount of 6 turns, the maximum diameter of a large turn in my design is 60 mm.

The secondary coil of the device is a regular coil wound on a polymer water pipe(without reinforcement) with a diameter of 15 mm. The coil is wound with enamel wire 0.01mm.kv turn per turn, in my device the number of turns is 980 pcs. Winding the secondary coil requires patience and endurance, it took me about 4 hours.

So, the device is assembled! Now a little about adjusting the device, the device consists of two LC circuits - primary and secondary! For proper operation devices - it is necessary to introduce the system into resonance, namely into resonance of the LC circuits. In fact, the system is brought into resonance automatically, due to the wide range of frequencies of the electric arc, some of which coincide with the impedance of the system, so all we have to do is optimize the arc and equalize the frequencies in terms of power in it - this is done very simply - we adjust the gap arrester. The arrester must be adjusted until best results in the form of arc length. An image of the working device is located below.

So the device was assembled and launched - now it works for us! Now we can make our observations and study them. I want to warn you right away: at least the currents high frequency are harmless to the human body (in terms of the Tesla transformer), but the light effects caused by them can affect the cornea of ​​the eye and you risk getting a corneal burn, since the spectrum of the emitted light is shifted to the side ultraviolet radiation. Another danger that lurks when using a Tesla transformer is an excess of ozone in the blood, which can lead to headaches, since large portions of this gas are produced during operation of the device, remember this!

Let's start observing a working Tesla coil. It is best to make observations in complete darkness, so you will most of all experience the beauty of all the effects that will simply amaze you with their unusualness and mystery. I made observations in complete darkness, at night and for hours I could admire the glow that the device produced, for which I paid the price the next morning: my eyes hurt like after a burn from electric welding, but these are trifles, as they say: “science requires sacrifices.” As soon as I turned on the device for the first time, I noticed a beautiful phenomenon - this is a glowing purple ball that was in the middle of the coil, in the process of adjusting the spark gap, I noticed that the ball moves up or down depending on the length of the gap, the only thing on this moment my explanation is the phenomenon of impedance in the secondary coil, which causes this effect. The ball consisted of many purple micro arcs that exited one area of ​​the coil and entered another, forming a sphere. Since the secondary coil of the device is not grounded, an interesting effect was observed - purple glows at both ends of the coil. I decided to check how the device behaves with the secondary coil closed and noticed another interesting thing: intensification of the glow and increase in the arc coming from the coil while touching it - an amplification effect on the face. A repetition of Tesla's experiment, in which gas-discharge lamps glow in the field of a transformer. When a conventional energy-saving gas-discharge lamp is inserted into the transformer field, it begins to glow, the brightness of the glow is approximately 45% of its full power, which is approximately 8 W, while the power consumption of the entire system is 6 W. Note: high-frequency noise occurs around the operating device. electric field which has a potential of approximately 4 kV/cm2. An interesting effect is also observed: the so-called brush discharge, a luminous purple discharge in the form of a thick brush with frequent needles up to 20 mm in size, reminiscent of an animal’s fluffy tail. This effect is caused by high-frequency vibrations of gas molecules in the field of a conductor; in the process of high-frequency vibrations, gas molecules are destroyed and ozone is formed, and the residual energy manifests itself in the form of a glow in the ultraviolet range. The most striking manifestation of the brush effect occurs when using a flask with an inert gas, in my case I used a flask from a HPS gas discharge lamp, which contains Sodium (Na) in a gaseous state, and a bright brush effect occurs, which is similar to the burning of a wick only with very frequent formation of sparks, this effect is very beautiful.

Results of the work carried out: The operation of the device is accompanied by various interesting and beautiful effects, which in turn deserve more careful study, it is known that the device generates a high frequency electric field, which causes the formation of large amounts of ozone, as a byproduct of ultraviolet glow. The special configuration of the device gives reason to think about the principles of its operation; there are only guesses and theories about how it works of this device, but no objective information was ever put forward, just as there was no thorough study of this device. At the moment, the Tesla transformer is collected by enthusiasts and used only for entertainment for the most part, although the device in my opinion is the key to understanding fundamental basis the universe that Tesla knew and understood. Using a Tesla transformer for fun is like hammering nails with a microscope... Super single effect of the device..? maybe... but I don't have it yet the necessary equipment to determine this fact.

We can see and purchase a miniature Tesla coil in the store in the form of a toy or decorative lamp. The operating principle is the same as Tesla himself. There is nothing different except the scale and tension.

Let's try to make a Tesla coil at home.

- 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 the 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 virtually no effect on the voltage.

Construction stages

Designing and building a Tesla coil is quite easy. For a beginner, this seems like a difficult task (I found it difficult too), but you can get a working coil by following the instructions in this article and doing small calculations. Of course, if you really want 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:

1. 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.
2. 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.
3. 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.
4. Manufacturing of the secondary winding. Use 900-1000 turns of 0.3-0.6mm enameled copper wire. The height of the coil is usually equal to 5 times its diameter. PVC drainpipe may not be the best, but available material for the reel. A hollow metal ball is attached to the top of the secondary winding, and its Bottom part 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.
5. Manufacturing of the primary winding. The primary winding can be made from thick cable, or better yet from copper tube. 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.
6. 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. The key word here is yet.

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 a 75mm drain PVC pipe and 5 meters of 6mm copper tube.

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 drain pipe height about 37cm. The length of the wire used was approximately 209 meters.

Inductance and capacitance of the secondary winding and 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 the 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. Right 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 a little more or less than this, since fast growth voltage due to resonance may 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, the total capacity of all assemblies is 41.3 nF.

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.

Characteristics

Oscillatory circuit
Transformer NST 4kV 35mA
Capacitor 3 × 24 275VAC 0.33μF
Arrester: two screws and a metal ball

Primary winding
Inner diameter 17cm
Winding tube diameter 6 mm
Distance between turns 3 mm
Primary winding tube length 5m
Turns 6

Secondary winding
Diameter 7.5 cm
Height 37 cm
Wire 0.3mm
Wire length approx. 209m
Turns: about 900

Invented in 1891 by Nikola Tesla, the Tesla coil was created to conduct experiments to study high-voltage discharges. This device consists of a power source, a capacitor, two coils between which a charge will circulate, and two electrodes between which a discharge will pass. The Tesla coil, which has found application in a great variety of devices (from particle accelerators and television to children's toys), can be made at home from radio components.

Steps

Part 1

Decide on the size and placement of your Tesla coil before you begin. You can do so much large reel Tesla as much as your budget allows; but keep in mind that the spark discharges created by the coil heat up the air, which expands greatly (resulting in thunder). The electromagnetic field created by the coil can damage electrical appliances, so it is better to place it in a remote location, such as a garage or workshop.

• To find out how long an arc you can get, or how much power the power supply will require, divide the distance between the electrodes in centimeters by 4.25 and square it to get the required power in Watts. Accordingly, to find the distance between the electrodes, multiply the square root of the power by 4.25. A Tesla coil capable of creating an arc 1.5 meters long would require 1,246 watts. A coil with a 1kW power supply can create a spark 1.37 meters long.

• Familiarize yourself with the terminology. Making a Tesla coil will require you to understand certain scientific terms and know the units of measurement. You will need to understand their meaning and meaning in order to do everything correctly. Here is some information you may find useful:

  • Electrical capacitance is the ability to accumulate and hold an electrical charge of a certain voltage. A device designed to store electrical charge is called a capacitor. The unit of measurement of electric charge is farad (denoted "F"). A farad can be expressed as 1 amp second (Coulomb) multiplied by a volt. Capacitance is often measured in fractions of a farad, such as microfarad (mF) - millionth of a farad, picofarad (pF) - trillionth of a farad.
  • Self-induction is the phenomenon of the occurrence of EMF in a conductor when the current passing through it changes. High-voltage wires through which low-ampere current flows have high self-inductance. The unit of self-inductance is henry (abbreviated as "H"). One henry corresponds to a circuit in which a change in current at a rate of one ampere per second creates an emf of 1 Volt. Inductance is often measured in fractions of a henry: millihenry ("mH"), thousandth of a henry, or microhenry ("µH"), millionth of a henry.
  • Resonant frequency is the frequency at which energy transmission losses are minimal. For a Tesla coil, this is the frequency of minimum losses during energy transfer between the primary and secondary windings. Frequency is measured in Hertz (abbreviated as "Hz"), defined as one cycle per second. Often, resonant frequency is measured in kilohertz ("kHz"), a kilohertz being equal to 1000 Hz.

• Gather all the necessary parts. You will need: a transformer, a high-capacitance primary capacitor, a surge arrester, a low-inductance primary coil, a high-inductance secondary coil, a low-capacitance secondary capacitor, and a device to dampen the high-frequency pulses that occur at high voltages during operation of the Tesla coil. More information about necessary details you will find in the section of the article “Making a Tesla Coil”.

  • The power source must, through an inductor, supply a primary or storage oscillatory circuit, which consists of a primary capacitor, a primary coil and a spark gap. The primary coil should be located next to the secondary coil, which is an element of the secondary oscillating circuit, but the circuits should not be connected by wires. Once the secondary capacitor has accumulated sufficient charge, it will release electrical discharges into the air.

• Make a primary capacitor. It can be made from many small capacitors connected in a circuit, which will accumulate equal shares of charge in the primary circuit. To do this, all capacitors must have the same capacitance. Such a capacitor is called a composite capacitor.

  • Capacitors small capacity and load resistors can be purchased at a radio parts store or you can remove ceramic capacitors from an old TV. You can also make capacitors from aluminum foil and plastic film.
  • To achieve maximum power, the primary capacitor must be fully charged every half power cycle. For a 60Hz power supply, charging should occur 120 times per second.

• Design the arrester. If you want to make a single discharger, you need to use a wire that is at least 6 millimeters thick so that the electrodes can withstand the heat generated during the discharge. You can also make a multi-electrode gap, a rotary gap, or cool the electrodes by blowing air. An old vacuum cleaner can be used for these purposes.

  Make a winding of the primary coil. The coil itself will be made of wire, but you will need a mold to wrap the wire around. Lacquered should be used copper wire, which you can buy at a radio parts store or remove from an unnecessary electrical appliance. The shape you wrap the wire around should either be cylindrical, such as a cardboard or plastic tube, or conical, such as an old lampshade.

  • The length of the wire will determine the inductance of the primary coil. The primary coil should have low inductance, so that it will consist of a small number of turns. The wire for the primary coil does not have to be solid; you can fasten sections together to adjust the inductance as you build.

• Assemble the primary capacitor, spark gap and primary coil into one circuit. This circuit forms the primary oscillatory circuit.

• Make a secondary inductor. Just like the primary coil, you need a cylindrical shape that you will wind the wire onto. The secondary coil must have the same resonant frequency as the primary to avoid losses. The secondary coil must be longer/taller than the primary coil to have more inductance and prevent the secondary from over-discharging which could cause the primary coil to burn out.

  • If you don't have the materials to make a large enough secondary coil, you can make a discharge electrode to protect the primary circuit, but this will cause most of the discharges to occur on that electrode and not be visible.

Tesla Transformer is a device invented by Nikola Tesla and bearing his name. It is a resonant transformer that produces high voltage and high frequency. The device was claimed by a US patent dated September 22, 1896, as “Apparatus for producing electric currents of high frequency and potential.”

Pros The most basic Tesla transformer consists of two coils - primary and secondary, as well as a spark gap, a capacitor, a toroid (not always used) and a terminal (shown as “output” in the diagram). The primary coil usually contains several turns of large diameter wire or copper tubing, and the secondary coil usually contains about 1000 turns of smaller diameter wire. The primary coil can be flat (horizontal), conical or cylindrical (vertical). Unlike conventional transformers, there is no ferromagnetic core. Thus, the mutual inductance between the two coils is much less than that of transformers with a ferromagnetic core. The primary coil, together with the capacitor, forms an oscillatory circuit, which includes a nonlinear element - a spark gap. The spark gap, in the simplest case an ordinary gas one, consists of two massive electrodes with an adjustable gap. Electrodes must be resistant to the flow of large currents through electric arc between them and have good cooling. The secondary coil also forms an oscillatory circuit, where the role of a capacitor is mainly played by the capacitance of the toroid and the own interturn capacitance of the coil itself. The secondary winding is often coated with a layer of epoxy resin or varnish to prevent electrical breakdown. The terminal can be made in the form of a disk, a sharpened pin or a sphere and is designed to produce predictable spark discharges of long length. Thus, the Tesla transformer consists of two connected oscillatory circuits, which determines its remarkable properties and is its main difference from conventional transformers. For full operation of the transformer, these two oscillatory circuits must be tuned to the same resonant frequency. Typically, during the tuning process, the primary circuit is adjusted to the frequency of the secondary by changing the capacitance of the capacitor and the number of turns of the primary winding until the maximum voltage is obtained at the output of the transformer.

1. TESLA TRANSFORMER DIAGRAM

As you can see, this diagram has a minimum of elements, which does not make our task any easier. After all, for it to work, you need to not only assemble it, but also configure it! Let's start in order: MOTS: there is such a transformer in the microwave. It is a regular power transformer with the only difference that its core operates in a mode close to saturation. This means that despite its small size, it has a power of up to 1.5 kW. However, there is also negative sides in this mode of operation. This is a high idle current, about 2-4 A, and high heat even without load, I am silent about heating with load. The usual output voltage of the MOT is 2000-2200 volts with a current of 500-850 mA. For all MOTs, the “primary” is wound at the bottom, the “secondary” at the top. This is done to ensure good insulation of the windings. On the “secondary”, and sometimes on the “primary”, the filament winding of the magnetron is wound, about 3.6 volts. Moreover, between the windings you can see two metal jumpers. These are magnetic shunts. Their main purpose is to close part of the magnetic flux created by the “primary” and thus limit the magnetic flux through the “secondary” and its output current at a certain level. This is done due to the fact that in the absence of shunts, during a short circuit in the “secondary” (during an arc), the current through the “primary” increases many times and is limited only by its resistance, which is already very small. Thus, the shunts prevent the trans from overheating quickly when the load is connected. Although the MOT gets hot, they put a good fan in the stove to cool it and it doesn’t die. If the shunts are removed, then the power delivered by the trans increases, but overheating occurs much faster. Shunts on imported MOTs are usually well filled with epoxy and are not so easy to remove. But it is still advisable to do this; the drawdown under load will be reduced. To reduce the heat, I can recommend putting the MOT in the oil. I ask amateurs to refuse this work. Danger High voltage. Lethal to life. Although the voltage is small compared to the line, the current strength, a hundred times greater than the safe limit of 10 mA, will make your chances of staying alive almost equal to zero. I may upset some people by reporting that the ILO, although ideal source power supply for Tesla coils (small-sized, powerful, does not die from RF like NST), but its price ranges from 600 to 1500 and more rubles. In addition, even if you have that kind of money, you will have to run around radio markets and stores quite a bit in search of it. Personally, I have never found an imported ILO, neither new nor used. But I found an MOT from the Soviet Electronika microwave oven. He has much large sizes than imported ones and works like a regular trans. It is called from TV-11-3-220-50. Its approximate parameters: power about 1.5 kW, output voltage ~2200 volts, current 800 mA. Decent parameters. Moreover, on it, in addition to the primary, secondary and filament, there is also a 12 V winding, just to power the cooler for the Tesla spark generator. The author of our Tesla used the following hacks:

CAPS: This means high-voltage ceramic capacitors (series K15U1, K15U2, TGK, KTK, K15-11, K15-14 - for high-frequency installations!) The most difficult thing is to find them. We present an identikit:

HF filter: respectively, two coils that perform the function of filters from high frequency voltage. Each contains 140 turns of varnished copper wire 0.5 mm in diameter. Very clearly visible in this figure:

Iskrovik: Iskrovik is needed to switch the power supply and excite oscillations in the circuit. If there is no spark switch in the circuit, then there will be power, but there will be no oscillations. And the power supply begins to siphon through the primary - and this is a short circuit! As long as the spark switch is not closed, the caps are charged. As soon as it closes, oscillations begin. Therefore, they install ballast in the form of throttles - when the spark plug is closed, the throttle prevents the flow of current from the power supply, it charges itself, and then, when the spark gap opens, it charges the caps with double the anger. Yes, if the socket had 200 kHz, the arrester would naturally not be needed.