What can be cooked from squid: quick and tasty

DIY Tesla transformer

Our working model of a homemade Tesla transformer in action

1. Description: Tesla coils are the simplest transformer consisting of two coils without a common core. The primary winding (primary) has several (3-10) turns of thick wire. The secondary (high-voltage) winding contains many more turns, about 1000. Tesla transformer has a transformation ratio 10-50 times higher than the ratio of the number of turns of the secondary winding to the number of turns of the primary. The output voltage of a Tesla transformer can be as high as several million volts. This voltage at the resonant frequency is capable of creating impressive electrical discharges in the air, which can be of considerable length, depending on the power of course.

the use of the simplest Tesla coil in everyday life.

2. Invention: Tesla Transformer in the form that we know, was the result of one of the experiments in Colorado Springs (USA) that took place back in 1899. The forerunner of the invention was the discovery made by Nikola Tesla in 1888 of the phenomenon of a rotating magnetic field and the construction of an electric generator of high and ultra-high frequencies. In 1891, the scientist creates a resonant transformer, which allows obtaining high-frequency voltage with an amplitude of up to several million volts. In his research, Nikola Tesla proved the possibility of creating a standing electromagnetic wave. The very invention outwardly seems very simple and uncomplicated, in fact, the most difficult thing in Tesla's transformer is the power circuit for the primary winding of the transformer.

3. Experiment: working with a giant coil, Tesla came to the construction of an entire tower several tens of meters high, which was crowned with a large copper hemisphere, and when the installation was turned on, spark discharges up to forty meters long appeared. Lightning was accompanied by thunderclaps, audible for 24 kilometers. Around the tower itself, during its operation, a huge ball of light was burning. Walking along the street, people shied away in fright with horror, watching sparks jump between their legs and the ground. Horses received electric shocks through iron horseshoes. On many, including significantly distant, metal objects, blue halos appeared - "the lights of St. Elmo".

Wardencliff Tower at Nikola Tesla Laboratory 1901-1917 - the first wireless telecommunication tower

The man who set up all this electrical phantasmagoria in 1899 from his laboratory in Colorado Springs had no intention of scaring people. His goal was different, and it was achieved: within twenty-five miles from the tower, to the applause of the observers, 200 light bulbs lit up at once. The electrical charge was transferred without any wires.

4. How to make the simplest Tesla coil: We take any high voltage source (MINIMUM 1.5 kV and generally get used to the fact that now volts do not exist, there is only kV, and 1.5 kV is as small as 1.5V in ordinary life), it is better to take at least 5 kV, we connect it to any capacitor for the required voltage (if the capacitance is too large, then a diode bridge will also be needed, but first it is better to experiment with small capacitances).

Then, through the spark gap, two wires, wound with electrical tape, so that their bare ends look in one direction (by bending the wire of the wire, we adjust the gap, which is configured for breakdown at a voltage slightly higher than the source voltage, the current is variable, so that at the peak the voltage is higher than the nominal) , connect this case to the primary winding of the coil (for our parameters it is better to take 5-6 turns). For the secondary winding, 150 turns will be enough (you can wind it on a regular cardboard tube) and, if you did everything correctly, you will get a discharge of 1 cm if you bring the coil leads closer and a rather noticeable corona if you dilute them. Yes, do not forget to properly ground one lower terminal of the secondary winding.

The simplest Tesla transformer at work. To create it, a high-voltage power supply was needed.

The purpose of this article and - show how you can make a real Tesla transformer (coil) from scratch with your own hands. So, let's begin!

5. Hardware requirements: for Tesla, which is not ashamed to show, you already need to sweat.

a) The input voltage needs to be at least 6 kV, otherwise the spark spark will not work stably (the setting will get lost).
b) The sparkler should be made of massive pieces of copper, it is desirable to fix them honestly in the desired position.
c) The input power is at least 50W, but better than 100+.
d) The capacitor and the primary winding must form an oscillatory circuit that resonates with the secondary winding. The secondary winding can have many multiple resonances (for example, in our circuit it resonates at 200, 400, 800 and 1200 kHz, I don’t know why this is so, but this has been tested experimentally on precision equipment), and some are stronger, while others are weaker (the first is not necessarily the most strong) and they depend on the location of the primary winding. I don’t know how to determine these frequencies without a frequency generator - I’ll have to use the “scientific poke” method, rewinding the primary winding and changing the capacitance of the capacitor.
e) You will also need either a relatively small capacitance of the capacitor (so that it is charged to a high voltage with an alternating current), or a diode bridge for rectifying the current (with a bridge, it’s somehow safer for me - you can connect any capacitance, but there you need a resistor to discharge it, after turning off the power or manually short-circuit it, otherwise it shocks VERY painfully).
f) The primary winding must be well insulated from the secondary, otherwise it will break through on it. The secondary winding must also have good turn-to-turn insulation, otherwise a crown will come out of every scratch on the varnish, or the whole coil will glow.

Now let's talk about how to create a reel like the one at the top!

6 DIAGRAM OF THE TESLA TRANSFORMER

A schematic diagram of a Tesla transformer, according to which our coil is assembled.

As you can see, there are a minimum of elements in this scheme, which does not make our task any easier. After all, in order for it to work, it is necessary not only to assemble it, but also to configure it! Let's start in order.

7. Safety principles:

Before starting any practical work related to electricity, it is very important for yourself to assess all its dangers and prevent possible risks. Remember that a lethal current for a person is a pitiful 0.1 Ampere, and a non-letting one is an alternating current, which, due to periodic impulses, causes a person to stick to a current source, arises at a force of 0.025 amperes;

Remember the danger when working with electricity!

When exposed to electrical voltage, the victim always receives a shock, but its consequences can be different: from cramps in the fingers of the extremities and their tremors, from unpleasant sensations of heating and burning to cessation of breathing and cardiac fibrillation (random contraction) and its complete stop. In the latter case, the blood stops moving through the vessels, which is why the person dies. In addition, electric current is dangerous for a person, since at certain values ​​of its strength, the effect of sticking to bare wires is created due to excessive stimulation of nerve fibers by electricity. One of the causes of death from electric shock can be mechanical injury as a result of involuntary muscle contraction. Loss of vision may occur due to the effect of the formed electric arc on the retina. And, if you do not have the proper practical working skills, then practice first on simpler things before starting a large project like this.

8. Tesla transformer power circuit:

8.1. MOTS: there is such a transformer in the microwave. It is a conventional 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 are also downsides to this mode of operation. This is a large no-load current, about 2-4 A, and strong heating even without a load, I am silent about heating with a load. The normal output voltage of the ILO is 2000-2200 volts at a current of 500-850 mA.

ILO - Power Transformer.

For all ILOs, the primary is wound at the bottom, the secondary is at the top. This is done for 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 a 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 (with 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 trance from overheating quickly when the load is connected. Although the ILO heats up, they put a fan in the stove to cool it down and it does not die. If the shunts are removed, then the power delivered by the trance increases, but overheating occurs much faster. Shunts from imported MOTs are usually well sealed with epoxy and are not easy to remove. But it is still desirable to do this, the drawdown under load will decrease. To reduce heating, I can advise you to immerse the ILO in oil, but do it in such a way that the oil, in the event of overheating or even fire, could not cause harm.

Battery from ILO transformers to power our Tesla coil

We used a battery of four MOTs, assembled in a similar way to our circuit. Remember. that the voltage on the secondary winding is many times higher than the mains voltage and is deadly, beware of arc discharges and do not work without removing the voltage!

8.2. Condensing unit - Caps: Caps mean high-voltage ceramic capacitors (series K15U1, K15U2, TGK, KTK, K15-11, K15-14 - for high-frequency installations!) The most difficult thing in caps is to find them.

Caps - high voltage capacitor unit

8.3. High Pass Filter: respectively, two coils that function as high-frequency voltage filters. Each has 140 turns of lacquered copper wire 0.5 mm in diameter.

High-pass filter and capacitor unit

HF filter and CAPs - capacitor unit for Tesla power supply

8.4. Iskrovik: A sparkler is needed to switch the power supply and excite oscillations in the circuit. If there is no spark in the circuit, then there will be power, but there will be no fluctuations. And the power supply starts to siphon through the primary - and this is a short circuit! Until the spark is closed, the mouthguards are charged. As soon as it closes, oscillations begin. Therefore, they put ballast in the form of chokes - when the spark is closed, the choke prevents the current from flowing from the power supply, it charges itself, and then, when the spark gap opens, charges the caps with doubled anger. And yes, if there were 200 kHz in the outlet, the spark gap would naturally not be needed.

A spark spark for excitation of oscillations in the Tesla coil circuit

Spark spark for excitation of oscillations in the power supply circuit of the Tesla coil

8.5. Thor and Tesla coil: Finally, the turn came to the Tesla transformer itself. The primary winding of the Tesla coil consists of 7-9 turns of very large cross-section wire, however, a plumbing copper tube is suitable. The secondary winding contains from 400 to 800 turns, here you need to adjust. The primary winding is energized. At the secondary, one terminal is reliably grounded, the second is connected to the TORU (lightning emitter). A torus, a kind of conductive donut, can be made from a conventional ventilation corrugation.

Winding a Tesla coil is a time consuming and meditative exercise

Tesla coil before assembly

8.6. A small video about our homemade Tesla coil:

9. Practical application. The transformer was used by Tesla to generate and propagate electrical vibrations aimed at controlling devices at a distance without wires (radio control), wireless data transmission (radio) and wireless power transmission. At the beginning of the 20th century, the Tesla transformer also found popular use in medicine. Patients were treated with weak high-frequency currents, which flowing over a thin layer of the skin surface did not harm the internal organs (see: skin effect, Darsonvalization), while exerting a "tonic" and "healing" effect. A circuit similar to this transformer is used in the ignition systems of internal combustion engines, but there it is low-frequency.

Tesla's transformer is not widely used today. It is produced by many amateurs of high-voltage technology and the accompanying effects. It is also sometimes used to ignite gas discharge (including faulty) lamps and to find leaks in vacuum systems. There is a theory that it was used to create radio interference.

Some create rides, other lights and magic tricks. one eccentric did manage to create a Christmas tree. His colors were obtained by applying different substances to the emitter. For example, if you apply a solution of some kind of boric acid, then the crown will be green. If manganese, then it is kind of bright blue, if lithium, then crimson. So, the Tesla coil in the hands of a modern person has turned into a toy and nothing more.

Tesla coil application

This should represent an alarm. Although it is quite obvious that such proximity can be fatal for the car's electrical equipment =)

I have my own idea for using a Tesla transformer, but more on that another time. 🙂

________________________________________________________________________

P.S. I express my gratitude to the creator of our Tesla coil,

Larionov A.

for the materials provided!

Nikola Tesla is truly a genius inventor of all time. He practically created the entire modern world. Without his inventions, we would not have known about the electric current for a long time that we know now.
One of Tesla's brightest and most amazing inventions is his coil or transformer. Which perfectly demonstrates the transmission of energy at a distance.
To experiment, delight and surprise your friends, you can put together a simple but workable prototype at home. This does not require a large number of scarce parts and a lot of time.

To make a Tesla Coil you will need:

• Bank from CDs.
• A piece of polypropylene tube.
• Switch.
• Transistor 2n2222 (domestic type kt815, kt817, kt805, etc. can be used).
• Resistor 20-60 KOhm.
• Wires.
• Wire 0.08-0.3 mm.
• 9V battery or other 6-15V source.

Instruments: a clerical knife, a hot glue gun, an awl, scissors and maybe another tool that is found in almost every home.

DIY Tesla coil making

Which is made by their hands... I hope that the information described below will be useful to readers and will be used in the manufacture of various homemade, which are based on the principles of electricity.

Step 1: Danger

Unlike other experiments using high voltage, the discharge from the coil can be very dangerous. Your nervous system and circulatory system can be seriously damaged. Do not touch the coil under any circumstances.

If this is your first project of this kind, ask someone with experience to help you and follow the safety guidelines.

Step 2: Collect materials

Secondary coil:

• Plastic pipe 38 mm in diameter (the longer the better);
• About 90 m of copper enameled wire with a diameter of 0.5 mm;
• 38mm plastic adapter;
• 38mm threaded metal floor flange;
• Enamel paint in a spray can;
• A round, smooth metal object is a charge discharge terminal.

Primary coil:

• About 3m thin copper pipe.

Capacitors:

• 6 glass bottles;
• Kitchen salt;
• Oil (I used rapeseed oil);
• Aluminium foil.

A high voltage power supply that outputs about 9 kV and 30 mA.

Step 3: winding the secondary winding

Let's make a small hole at the top of the pipe. We will pass one end of the wire into it and wrap it around the pipe. Slowly and carefully, we begin to wind the coil, making sure that the wires do not cross, and there are no gaps. This step is the hardest and most tedious, but the time will be well spent - you will end up with a very high quality reel. Every 20 turns, stick the tape on the wire - it will act as a barrier if the coil starts to unwind. Upon completion of the work, wrap the electrical tape tightly around the top and bottom of the coil and spray on the winding with 2 or 3 layers of enamel.

For winding the coil was made homemade, which consists of a motor (3 revolutions per minute) and a bearing.

Step 4: Prepare the base and wind the primary winding

Align the metal stand with the center of the bottom board and drill holes for the bolts. Install the bolts upside down. This will secure the primary base with nuts from the outside. crafts... Then we will screw it to the base. Take a copper tube and form an inverted cone out of it.

Discharger - two bolts sticking out of a wooden board. They are adjustable so that tuning can be done.

Step 5: assembling the capacitors

Instead of buying capacitors, let's make them by their hands... For this we need salt water, oil and aluminum foil. Wrap the bottle with foil and fill it with water. Try to pour an equal amount of water into each bottle, as the same amount will help maintain consistent power output. The maximum amount of salt that you can dilute in water is 0.359 g / ml (however, all calculations ended with a strong saline solution, so I reduced the amount to 5 grams). Make sure you are using the "correct" amount of salt per volume of water. Now pour a few ml of oil into the bottle. Punch a hole in the cover and insert a long wire through it. Now you have one fully functioning capacitor, you need to make 5 more.

Additionally, to keep the bottles together, make or find a crate for them.

If you are using a 15kV 30mA PSU, you need to use 8-12 bottles, not 6!

Step 6: Putting It All Together

We divorce the wiring in accordance with the diagram. The secondary ground cannot be placed on the ground of the building's electrical network, in which case it will “burn” all electrical appliances in your home.

Characteristics of my coils:

• 599 turns on the secondary coil;
• 6.5 turns on the main coil.

Step 7: Run the installation

Take it outside the first time you start it up as it is really not safe to run such a powerful device indoors (high risk of fire). Flip the switch and enjoy the light show. My PSU with 9kV and 30mA allows the coil to emit 15cm of spark.

Step 8: For the future ...

There are a few things that need to be changed in my next installation. The first is the design of the primary winding. It should be more tightly rolled up and consist of more turns. The second is to make the spark gap better.

Thank you for the attention!

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. After a few years, I found my old coil, counted it a little and continued building. And again I abandoned it. In 2007, a friend showed me his reel, reminding me of my unfinished projects. I found my old reel again, counted everything and this time completed the project.

Tesla coil is a resonant transformer. These are mainly LC circuits tuned to one resonant frequency.

The high voltage transformer is used to charge the capacitor.

As soon as the capacitor reaches a sufficient level of charge, it is discharged to the spark gap and a spark jumps there. A short circuit occurs in 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. When properly tuned, a very high voltage will be at the top of the secondary winding, resulting in impressive discharges in the air. Unlike traditional transformers, the ratio of turns between primary and secondary windings has little or no effect on voltage.

Construction stages

It is pretty easy to design and build a Tesla coil. For a beginner, this seems like a daunting task (it also seemed difficult to me), but you can get a working coil by following the instructions in this article and doing some small calculations. Of course, if you want a very powerful coil, there is no way other than learning theory and doing a lot of calculations.

Here are the basic steps to start with:

1. Choice of power supply. Transformers used in neon signs are probably best for beginners as they are relatively cheap. I recommend transformers with an output voltage of at least 4kV.
2. Arrester manufacturing. It might just be two screws screwed a couple of millimeters apart, but I recommend putting in a little more effort. The quality of the arrester greatly affects the performance of the coil.
3. Calculation of the capacitance of the capacitor. 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 efficient solution would be to assemble the capacitors. If you don't want to spend money, you can try making your own capacitor, but it may not work and its capacitance is difficult to determine.
4. Manufacturing of a secondary winding. Use 900-1000 turns of 0.3-0.6mm enamelled copper wire. The height of the coil is usually 5 times its diameter. PVC downpipe may not be the best coil material available. A hollow metal ball is attached to the upper part of the secondary winding, and its lower part is grounded. For this, it is advisable to use a separate grounding, because when using common house grounding, there is a chance to damage other electrical appliances.
5. Manufacturing of the primary winding. The primary winding can be made of thick cable, or better still, copper tubing. The thicker the tube, the less resistive losses. 6mm pipe is sufficient for most coils. Remember that thick pipes are much more difficult to bend and copper will crack with multiple bends. Depending on the size of the secondary winding, 5 to 15 turns in steps of 3 to 5 mm should be sufficient.
6. Connect all the components, tune 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 work with high voltages!

Also note that no transformer protection circuits have been mentioned. They have not been used, and so far there are no problems. The key word here is for now.

Details

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

Secondary winding

Secondary winding top and bottom covered with plastic insulation to prevent breakdown

The secondary was the first component to be manufactured. I wound about 900 turns of wire around a drain pipe 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. With this 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 with foil. I couldn’t smooth the foil on the ball well enough and decided to make a toroid. I made a small toroid by wrapping aluminum tape around a corrugated tube that was coiled into a circle. I was not able to get a very smooth toroid, but it works better than a sphere because of its shape and due to its larger size. A plywood disk was placed under it to support the toroid.

Primary winding

The primary winding consists of 6 mm diameter copper tubes spirally wound around the secondary. The inner diameter of the winding is 17cm, the outer one 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 can be loosely coupled.
The primary winding together with the capacitor is the LC generator. 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. The correct coil size must be experimentally selected, so it is better to make it too large than too small. My coil has 6 turns and is connected on 4 turns.

Capacitors

An assembly of 24 capacitors with a 10MΩ damping resistor on each

Since I had a large number of small capacitors, I decided to assemble them into one large one. The value of the 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, as a rapid rise in voltage due to resonance can damage the transformer and / or capacitors. Damping resistors provide little protection against this.

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

Each capacitor has its own 10 megohm damping resistor. This is important because individual capacitors can hold a charge for a very long time after the power has been disconnected. As can be seen from the figure below, the rated voltage of the capacitor is too low, even for a 4 kV transformer. To work well and safely, it must be at least 8 or 12 kV.

Arrester

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

Nikola Tesla, a scientist and inventor whose name is covered with legends, was born 162 years ago. He is credited with inventing the first, wireless transmission of electricity and even "death rays". But the real, studied and confirmed inventions of Tesla are impressive: he made a huge contribution to the study of electricity, radio waves and magnetic fields.

Tesla's main discovery is alternating current. Of course, the genius Serb did not invent it (as they sometimes write in popular articles), but only found practical application for it. Along the way, he designed an engine and an alternator, the "descendants" of which are still used today.

Components can be placed on a printed circuit board or by surface mounting - on MDF or cardboard.

And a few words about safety precautions. Despite the fact that the discharges of the Tesla coil do not harm a person due to the so-called "skin effect" (current passes through the surface of the skin), it is important to observe electrical safety when assembling and testing it. It is also not recommended to stay near a working coil for too long: a high-voltage field can negatively affect your well-being.

Now let's move on to assembling the device. We have already analyzed the power supply above, but here are five ways, how and from what to build a case, coils and a toroid.

Method one: "on the flute of drainpipes"

Here's what you need.

• Switch.
• 22k ohm resistor.
• 2N2222A transistor.
• Crown connector.
• PVC pipe d = 20 mm, piece length 85 mm.
• Battery "crown" 9V.
• Copper wire with a cross section of 0.5 mm.
• PVC-insulated wire with a cross section of 1 mm, a piece of 15-20 cm long.
• A piece of plywood or laminate with dimensions of approximately 20x20 cm.

The assembly order is almost the same as in previous models.

1. Let's start with coil L2. Wrap the copper wire around the pipe in one layer, turn to turn, stepping back from the edges by about 0.5 cm. Fix the first and last turn with paper tape so that the winding does not fly off.

2. Attach the spool pipe to the plywood or laminate base with hot melt glue. Also secure the switch, transistor and crown connector.

3. We make the coil L1. Wrap the insulated wire twice around the coil and also fix it with hot glue.

4. Connect the circuit to the circuit:

♦ the lower end of the secondary (long) coil wire - to the middle contact of the transistor;

♦ resistor - also to the middle contact of the transistor;

♦ the upper end of the primary (short) coil wire - to the resistor;

♦ the lower end of the primary winding wire - to the right contact of the transistor;

♦ contact of the resistor with the primary winding wire - to the contact of the switch;

♦ red wire of the "crown" connector (+) - to the middle contact of the switch;

♦ black wire of the "crown" connector (-) - to the left contact of the transistor.

After you insert the battery into the connector and press the switch, the coil will start working. It will not give visible discharges due to the low operating voltage, but it will be able to light the fluorescent lamp in your hand.

Bonus: a giant reel three meters high

This "recipe" was developed and tested by the user "Habr" zerglabs and his team. They created a coil about three meters high with an estimated power of about 30-40 kW. Enthusiasts chose a variation of the Tesla coil known as the DRSSTC - Dual Resonant Solid State Tesla Coil. It has a special "musicality": it emits sounds, the height of which can be controlled using the midi-console.

The team used:

• Copper wire 1.6mm.
• Sewer PVC pipe d = 30 mm, piece length 180 cm.
• Copper tube with a diameter of 22 mm.
• Aluminum pipes d = 50 mm.
• Plywood and fiberglass for frame details.

Build process:

1. Like the previous masters, zerglabs and his "accomplices" first wrapped the pipe with copper wire to make a secondary circuit. It was fixed on a plywood stand.

2. The secondary circuit was made from a copper tube that was placed in a slotted stand. Six turns, diameter 22 mm.

3. The team has built a special toroid that is easy to transport. It consists of plywood elements and bent aluminum pipes and, when assembled, looks like a skeletonized donut. As zerglabs explains, the field "wraps around" the toroid, so you can make it not solid.

4. Assembling the electrical part. IGBT modules are often used in the power inverter for large Tesla coils. For the giant coil, the team took two CM600DU-24NFH modules (600 amps continuous current, 1200 volts) and connected them in a bridge. The modules were fastened with copper busbars and equipped with electrolytic and film capacitors. An automatic starter (large power relay) and several power resistors were built into the control automation so that when the coil is turned on, it does not knock out the mains fuses.

The design also included a battery of capacitors: five of them with a total capacity of about 1.2 microfarads and a maximum voltage of 20 kilovolts. They were connected using copper plates.

The tricky and secret part of the giant coil is the frequency-modulating driver. It allows you to control the discharges, including in order to play the coils of the melody. But its scheme is the intellectual property of the developers.