How to Build a Tesla Coil: 13 Steps

2024 Author: Samantha Chapman | [email protected]. Last modified: 2023-12-17 09:13

The Tesla coil was conceived and presented in 1891 by the famous scientist Nikola Tesla. It is a device created to conduct experiments in the production of high voltage electrical discharges. It consists of a generator, a capacitor, a coil transformer, and is formed by several resonant electrical circuits placed so that the voltage has alternating maximum peaks between the two components, and finally a spark gap or a pair of electrodes in which the current passes, passing through the air and forming a spark. Tesla coils are used in many devices, from particle accelerators to televisions or toys, and can be built with materials purchased specifically for this purpose or with salvaged elements. Here's how to do it.

Steps

Part 1 of 2: Designing the Tesla Coil

Step 1. Evaluate the size and where the coil will be placed before building it

The size is limited only by your budget; however, the small lightning bolts generated by the device develop heat and expand the air around them (basically, just as lightning creates thunder). Their electric fields can also irreparably damage home appliances and electrical devices in general, so it's probably wiser to build and activate your Tesla coil in a relatively isolated location, such as a garage or shed.

• To get an idea of the length of the discharges it can reach, or the current required for the coil to work, divide the length of the discharges, measured in inches (1 inch = 2.54 cm), by 1.7 and raise the result to square to get the power in watts. Conversely, to get the length (in inches) of the discharges, multiply the square root of the power (in watts) by 1.7. A Tesla coil producing a 60 inch (1.5 meter) discharge would require a power of 1., 246 watts to run (a Tesla coil powered by a 1 kilowatt generator creates discharges at least 54 inches long, or 1.37 meters).

  

  Step 2. Learn the terminology

  To design and build a Tesla coil it is essential to be familiar with some scientific terms and some units of measurement. You need to know them to understand how and why a Tesla coil works. Here are some concepts that will be useful for you to know:

  • Electric capacity is the ability of a body to store an electric charge or the amount of electric charge stored for a given voltage. A capacitor, more commonly known as a capacitor, is a device that stores energy. The unit of measurement of electrical capacitance is the farad (symbol "F"). Farad is defined as 1 amp * 1 second / 1 volt (or also, equivalently, 1 coulomb / 1 volt). Decimal units of the farad are commonly used since it is a very large unit of measurement compared to the value of the capacities encountered in everyday life. It is therefore normal to find the microfarad (symbol "μF"), which corresponds to one millionth of a farad, or the picofarad (symbol "pF"), which corresponds to one billionth (10^-12) of farad.
  • Inductance, or self-inductance, expresses the amount of volts that circulate in a circuit based on the amount of current. (High voltage lines carry high voltage but little current and have high inductance.) The unit of measure for inductance is the henry (symbol "H"). A henry is defined as 1 volt * 1 second / 1 ampere. Smaller units are generally used, such as millihenry (symbol "mH"), which corresponds to one thousandth of a henry, or microhenry (symbol "μH"), which corresponds to one millionth of a henry.
  • The resonant frequency is the frequency at which the resistance to energy transfer touches a minimum. For a Tesla coil, this indicates the optimal condition for the transfer of electrical energy between the primary and secondary coil. The unit of measurement for frequency is hertz (symbol "Hz"), which is defined as 1 cycle per second. Generally, the kilohertz (symbol "kHz") is used as the unit of measurement, which corresponds to 1000 hertz.

  

  Step 3. Get the materials needed for construction

  You will need a generator, a high-capacity primary capacitor, a spark gap or the elements to build it, a low-inductance coil primary inductor, a high-inductance coil secondary inductor, a low-capacity secondary capacitor, and something to damp or block. the high-frequency sound pulses that are generated by the Tesla coil when it is in operation. For more information on materials, read the second section of the article, "Building a Tesla Coil".

  The generator / transformer transmits energy to the primary circuit which connects the primary capacitor, the primary coil inductor and the spark gap. The primary coil inductor should be placed close to (but not in contact with) the secondary inductor, which is connected to the secondary capacitor. Once the secondary capacitor has stored a sufficient electrical charge, this will be released through electrical discharges

  Part 2 of 2: Building a Tesla Coil

  

  Step 1. Choose your power transformer

  Its power determines the maximum size of your Tesla coil. Most Tesla coils are powered by a transformer that delivers a voltage between 5,000 and 15,000 volts, at a current between 30 and 100 milliamps. You can get a transformer on the Internet, at a specialty store, or by recycling it from a lamp or neon sign.

  

  Step 2. Mount the primary capacitor

  The best way to build this is to connect multiple capacitors in series, so that the total primary circuit voltage is divided equally among all capacitors. To achieve maximum efficiency, each individual capacitor must have a capacity equal to that of the other capacitors in the series. This type of capacitor is also called MMC (from English "Multi-Mini-Capacitor").

  • Smaller capacitors (and their associated leakage resistors) can be purchased on the Internet or at some electronics stores; alternatively, you can take apart old TVs and recover the ceramic capacitors present in them. It is also possible to build them with polyethylene sheets and aluminum sheets.
  • To maximize the output power, the primary capacitor should be able to reach its maximum capacity every half cycle of the supply frequency. For example, if you have a 60Hz power supply, the capacitor should max out 120 times per second.

  

  Step 3. Decide how to make the spark gap

  If you plan to use a single one, you will need screws at least 6mm thick for the device to withstand the heat generated by the electrical discharges that form between the terminals. You can also connect multiple spark gaps in series, use a rotary spark gap or cool the system with compressed air to keep the temperature under control (in this regard, you can use a suitably modified vacuum cleaner to blow the air).

  

  Step 4. Build the primary coil inductor

  The spool itself is made of wire, but you will need a holder to wind it in a spiral. The wire should be enameled copper, which you can buy at a hardware store, DIY store, or by recycling the power cord from an old, discarded appliance. The object to wrap the cord on can be cylindrical, like a plastic or cardboard tube, or conical, like an old lampshade.

  The length of the cable determines the inductance of the primary coil. This must have a low inductance, so it is advisable to make relatively few windings during construction. Instead of using a solid wire, you can use shorter pieces of wire and connect them as needed to conveniently vary the inductance value

  

  Step 5. Connect the primary capacitor with the spark gap and primary coil inductor

  This way you get the primary circuit.

  

  Step 6. Build the secondary coil inductor

  As with the primary coil, wrap the thread around a cylindrical object. In order for the Tesla coil to work efficiently, the secondary coil must have the same resonant frequency as the primary one; however, the secondary coil must be longer than the primary one, both because it must have a larger inductance, and because in this way it is avoided that there are electric discharges that start from the secondary circuit and hit the primary one, damaging it.

  If you don't have the material to build a sufficiently long secondary coil, you can work around the problem by building a small railing to act as a lightning rod (this, however, means that much of the Tesla coil's discharges will hit the lightning rod rather than dance in the air)

  

  Step 7. Build the secondary capacitor

  The secondary capacitor, or discharge terminal, can have any rounded shape: the 2 most common shapes are the torus (ring or donut shape) and the sphere.

  

  Step 8. Connect the secondary capacitor to the secondary coil inductor

  This way you get the secondary circuit.

  The grounding of the secondary circuit should be separated from the grounding of the circuits of the electrical network in your home that supply current to the transformer, to prevent the electric current that passes from the Tesla coil to the ground from propagating in the circuits and damaging the devices that can be connected to the sockets. You can ground the circuit using a metal stake driven into the ground to avoid possible damage

  

  Step 9. Build the Pulse Choke Coils

  They consist of small, simple inductors that prevent the impulses generated by the spark gap from damaging the transformer. You can build one by wrapping thin copper wire around a narrow tube, like that of an ordinary ballpoint pen.

  

  Step 10. Assemble the components

  Place the primary loop next to the secondary loop, then connect the power transformer to the primary loop through the choke coils. Once the transformer is connected to the mains, your Tesla coil is ready for use.

  If the primary coil has a large enough diameter, you can insert the secondary coil inside the primary

  Advice

  • To control the direction of the discharges released by the secondary capacitor, place metal objects near it (but not in contact with it). The discharge will form an arc between the capacitor and the object. If the object contains a circuit in which a device capable of emitting light, such as an incandescent light bulb or a fluorescent lamp, is inserted, the electricity generated by the Tesla coil will be able to power it and then turn it on.
  • Designing and building an efficient Tesla coil requires a certain familiarity with the concepts of electromagnetism and with fairly complex mathematical equations. You can find these equations, along with many tools for calculating the quantities involved, at https://deepfriedneon.com/tesla_frame6.html (in English).

  Warnings

  • Transformers for neon signs, such as those of recent production, have a differential switch so they cannot be activated with the coil.
  • It's not easy to build a Tesla coil, unless you already have some engineering or electronics knowledge.