What is Tesla coil? – Everything You Need to Know

Necessity, they say, is the mother of invention. It will not be an exaggeration to consider Tesla coil one such invention. After the invention of electricity, current was only transferred using wires connected from one equipment to another. In a bid to transmit electricity wirelessly, Nikola Tesla in 1891 invented the Tesla coil.

The coil, fortunately, didn’t need a big circuit, hence making it very small and mobile. So it technically became part of our everyday lives, just like remote controls, smartphones, computers, etc. And it has been used for various appliances and doing cool stuff like shooting lighting bolts and creating electron winds. But What is Tesla coil, anyway?

uses of tesla coil in daily life

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Tesla Coil Discussed At Length

Tesla coil is a device used in creating high electrical currents. This information merely should suffice to answer why was the tesla coil invented? The coil was invented by Nikola Tesla with the aim of supplying power without connecting wires. The coil principle is quite simple—using electromagnetic force and resonance. Therefore with a copper wire and pipe, even an electrical student can create a tesla coil capable of supplying up to 250,000 volts.

A Tesla coil typically has two parts—the primary and secondary coil, each of which has its capacitor. This capacitor typically holds electrical energy, just like batteries. Both coils and their capacitors are connected by a spark gap which helps create a spark of electric current. Because this spark gap is adjustable, it gives the operator control over the voltage the coil generates.

To, however, generate such high voltage, a Tesla coil needs an external power source—typically a high-voltage transformer. And that could be a resonant, an oscillation, or a radio frequency transformer. This transformer supplies current to the primary coil. The primary coil, in turn, supplies the secondary coil power, which invariably powers equipment kept close to it without wires.

How to make a Tesla coil

A Tesla coil typically consists of a power source, capacitors, and coil transformer. But this won’t be like the actual Tesla coil. It would be rather a mini Tesla coil.  So to complete a mini tesla coil project, you will need the following:

  • 1 PVC Pipe
  • A thin copper wire
  • A thick copper wire (a breadboard wire, also known as hook-up wire, can also suffice)
  • Sandpaper (or scissors used for removing copper wire enamels)
  • A battery and battery clip
  • 1 2N2222A transistor
  • 1 22K ohm resistor
  • A switch
  • A wooden platform( Cardboard could also suffice
  • A small plastic ball
  • Aluminum foil to cover the ball

To build a mini tesla coil.

  • First, build the secondary coil. To do this, take the PVC and wrap it with your thin copper wire; ensure there is no space between. Depending on the length of your PVC pipe, it might take about 350-700 turns to wound the wire around the PVC pipe. Generally, the secondary coil takes a long time to make than the primary.
  • Tap the secondary coil on the wooden platform
  • To make the primary coil, wound the thicker copper wire around the PVC pipe or secondary coil about 2-5 times, depending on what you want. Use sandpaper to remove the enamel from the copper wire tip.
  • Using a soldering iron (or alternatives that can melt wires together), solder the resistor to the transistor. Then the bottom of the primary coil to the base. Also, solder one end of the secondary coil to the collector. After which, solder the battery clip positive terminal to the switch and the negative terminal to the emitter pin.
  • Lastly, solder the other end of the secondary coil and the switch-free pin to the other end of the resistor. This should light up the fluorescent bulb. But to better demonstrate the reason the Tesla coil was invented (transferring power wirelessly), take the next step.
  • Wrap the plastic ball with the aluminum foil and put it on the secondary coil. This should create a mini tesla coil. At this point, the coil can light up your bulb if placed near it without wires.

While the procedure above describes how to make a Tesla coil, you may better understand the process by looking up this video.

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What are Tesla coils used for?

Tesla coils typically generate high voltage used to power equipment without connecting wires. So if you’re asking, what are Tesla coils used for? They come useful in the following areas:

  • Radios
  • Television
  • Aluminum welding
  • Tesla coils are used for spark plug ignition in cars
  • They are useful in creating artificial lighting bolts
  • Used to power vacuum system leak detectors
  • Tesla music coils are useful in the entertainment and educational industry

Are Tesla coils dangerous

Tesla coils produce high voltage, which the human body can’t comprehend if they come in contact with. So are Tesla coils dangerous? Yes, they are. Eventually, every part of the device can produce shocks when in operation, with the transformer and wirings included. This is why it is important never to let them have direct contact with your body.

In fact, do not let your body touch any naked transmitter of electricity the coil is connected to. The power from this coil could burn a graphite pencil.

This means that, even if you don’t get a shock from a Tesla coil, you can get burnt badly, just like a graphite pencil, if your body touches the coil.

The coil also produces smells that are poisonous to living things. Encountering these drawbacks, you may be wondering, are tesla coils illegal? But the fact remains, they are not illegal despite their flaws; you just have to apply caution when creating or using them.

tesla coil project

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Q: What does a Tesla coil do?

A tesla coil typically produces high current. It uses a power transformer or any power source to produce a high voltage. The coil takes its power from a 120vAC to several kilovolts of transformer and circuit to produce incredibly high voltage.

The voltage generated can be as high as 1,000,000 or more and is released as an electrical arc. They are generally used to wirelessly power various applications such as fluorescent bulbs, television, radio, etc.

Q: Is a Tesla coil AC or DC?

Tesla coil is AC. The coil is typically a transformer with extremely high turns. And as such cannot work without altering the magnetic field. So it must be driven by AC excitation.

While several DC can work, they are less efficient than AC since the transformer will eventually get soaked. In fact, the primary coil are built with DC. However, the secondary coils are built with a high-frequency AC; no wonder it houses a high voltage.

Q: Why was the Tesla coil so important?

While Nikola Tesla built the coil to primarily generate high voltage, his major aim was to transmit this electrical current without using wires. And fortunately, it was the first wireless current transmitter ever made. So the coil is important because it can power appliances or be used for different things without wires.

Secondly, before the invention of the Tesla coil, regular standard core transformers were used to power stuff like telephone circuits and lighting systems. However, these conventional transformers cannot tolerate the frequency the tesla coils can withstand. The Tesla coil is also important because it gives more insight into electricity, its component, and how to assemble them.

Q: How does a Tesla coil transmit electricity?

Since it is already established that the coil transmits electricity. So how does a tesla coil work to transmit electricity? It works with a principle called resonance. The primary coil gets a huge amount of energy from its power source and eventually transfers it to the secondary coil, giving the secondary circuit enough power to transmit. Eventually, powering any device near it without wires. Here is a detailed explanation.

The device consists of a primary and secondary coil. The primary coil is attached to a power source and, with the help of its capacitor, extracts energy from the source. For the primary coil to get enough charge, it must be a good conductor of electricity—a reason it’s built with copper wires. When the primary coil gets enough charge, it breaks down the air resistance in the spark gap and flows out of the capacitor, creating a magnetic field.

The huge amount of energy quickly breaks down the magnetic field, generating power in the secondary coil. This current alternates between the two coils for some time and eventually builds up in the secondary coil and its capacitor. When the current in the secondary coil gets so high, it eventually powers appliances close to it without wires.

Q: How much electricity does a Tesla coil use?

How much electricity a Tesla coil uses depends on the amount of current it wants to generate and the power source. Generally, the higher its power source, the higher the voltage generated. An average tesla coil that transmits 2 to 4 arcs of electricity operates on 1000 watts.

Q: Why transistor is used in the Tesla coil?

A transistor acts like an on/off switch and transmits electric current through the primary coil. It ensures the AC frequency is proportional to the coil’s resonance using a feedback mechanism. That is, it ensures the secondary coil gets only the frequency needed.

But the beauty of it is with a transistor; you don’t need to adjust the coils manually. The transistor automatically tunes the mini tesla to the exact frequency needed by the secondary coil. With it, too little or too much power won’t be transmitted to the secondary coil.

Considering the usefulness of the transistor, can one make a tesla coil without a transistor? Yes, you can, but it’s a bit different from the above procedure. So here is a video explaining how to make a tesla coil without a transistor.

Q: Can you use a Tesla coil to power a house?

You cannot use a Tesla coil to power a house. A Tesla coil is a transformer, which means it gets power from another source and not a power source itself. So technically, it cannot power anything without being connected to a power source. So can a tesla coil power a house? No.

However, even if you decide to use it to power some bulbs or other electronics in your home, they may get damaged. Here is what happens. A Tesla coil requires a lot of energy from a source to produce a voltage that high to power your electronics. And in reality, the amount of energy it gets from its source will never be sufficient enough to power your appliances.

Q: What are the disadvantages of Tesla coil?

While the invention of the Tesla coil comes with enormous benefits, it has some flaws. The high radio frequency emitted from the coils is so high that it can cause skin burns and damage the nervous system.

So you may ask, can a Tesla coil kill you?

If the coil generates a very high voltage, like up to a megavolt, it can cause too much current to flow through your body and kill you instantly. It’s also very expensive since the cost of buying a large DC smoothing capacitor is high.

A Tesla coil price ranges from $30-$100 or more, depending on the coil size. Smaller coils can be built for under $100, with larger ones costing over $100. Lastly, for the coil to function well, it must be done perfectly. So it usually takes a lot of time to build one.

Q: Do Tesla coils produce ozone?

Tesla coils produce high quantities of ozone. The ozone is that smell you perceive or inhale around the coil, and it’s a product of partially burnt air and inert particles. And it’s quite toxic.  It is for this reason that it is always required to have adequate ventilation when building or operating the coil.

Aside from ozone, another thing that can hurt is the ultraviolet light produced by the spark gap in the Tesla coil. This light can easily burn your eye’s retina. Considering these, you may ask, can tesla coil be weaponized? Yes, they can. An enemy could intentionally produce coils emitting a large quantity of ozone. Imagine the air in your surroundings full of ozone.

Q: How much voltage does a Tesla coil produce?

A Tesla coil can produce between 50 volts to several millions of volts. However, how much voltage it produces depends on the size of the coil, which also points to the coil’s power source.

The volt supplied by a 120vAC transformer will differ from that supplied by a smaller transformer. Some coils use a transformer that can put out up to 5k to 15k volts with a current within 30 to 100 milliamperes.

Q: Can you build a Tesla coil?

Yes, you can build a Tesla coil. The process is quite easy though it takes a lot of time to complete. All you need to do is get all your materials beforehand, which we have listed above and follow the procedure highlighted above. There are also tons of videos of how to make a Tesla coil online, each with a different approach. So you can flow with the one you understand best.

However, understand that the coil has so many known and unknown flaws, one of which is its tendency to cause shock or burns due to the high voltage it supplies. So you may ask, is it illegal to build a tesla coil? Building tesla coils are not illegal but can be highly dangerous. So ensure you know your way around before attempting to build one.

Q: Is the Tesla coil still used?

While its application is limited, the Tesla coil is still very much used to date.  It is used to power radios, television, and other electronics. In cars, it comes handy in spark plug ignition. To be specific, smaller Tesla coils are used to detect leaks in scientific high vacuum systems. And also comes in handy in igniting arcs. They are also used for entertainment and educational displays.

Its application may be limited because of some known dangers involved in using this device. First, it emits a toxic smell that can harm the nervous system. The spark gap used in the plug also produces ultraviolet light, which can damage the retina of the eye. The device is also known for emitting high voltage, which can cause shock and severe burns.


Beyond doubt, the exclusive discussion has answered the question, what is a Tesla coil? A recap. A Tesla coil is an equipment used to create extremely high voltage, particularly to transmit electricity without wires.

The device gets its current from a power source and transmits this current to other devices placed near it without needing a wire. It’s used in radio, television, cars, and even entertainment and educational shows.

However, while it has enormous benefits, it can also be dangerous. The voltage produced by this device is so high that it can cause a shock or severe burns. It also emits ozone which is toxic and can harm the nervous system. The ultraviolet light produced by the coil can also destroy your eye’s retina. So, beware of the danger associated with this Tesla accessory.

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Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

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