How do you make a Tesla coil?

Answer 1

Difficulty: Moderately Challenging

== * Transformer * 5 sheets of 12 x 12 x 0.032 inch polystyrene * 4 10-inch square metal plates * 4 "L" brackets * 4 bolts with round end caps * One roll heavy gauge wire * One roll enameled wire * One 3-inch diameter PVC tube, 12 inches long * Varnish * Two 1 1/2 inch diameter PVC pipes, 6 inches long * Brass doorknob * 4 additional PVC pipes, slightly taller than transformer * Glue * Wood board == Step1 Find a transformer rated at 9,000 volts or better and 30 milliamps. Many people opt for neon sign Transformers, which are relatively easy to find. Others use oil furnace ignition transformers or automotive coil transformers, which produce much more subtle effects.

Step2 Make a capacitor by layering the five sheets of polystyrene alternating with the four metal plates. The plates can be copper or aluminum foil or just very thin aluminum plates.

Step3 Make the spark gaps with the four L brackets and the bolts. Put the round end caps on the ends of the bolts.

Step4 Wrap a heavy-gauge bare wire six or seven times around a cylinder form at least eight inches in diameter. Poke holes in four pieces of PVC pipe and thread the wire through to form your primary coil. The holes in the PVC should be about 1/8 inch apart.

Step5 Wind the enameled wire tightly around the three-inch PVC form for your secondary coil. This one should have about 500 turns. Varnish the coil with several heavy coats and make sure it dries evenly.

Step6 Wrap 20 turns of enameled wire on two separate 1½ inch diameter PVC pipes for your radio-frequency chokes (RFCs). == Step1 Mount the doorknob on top of the secondary coil. This acts as the top discharge terminal. Set the secondary coil inside the primary coil and attach both at the center of the piece of wood.

Step2 Attach the four remaining PVC pipes to the underside of the board. Attach the spark gaps, radio frequency chokes, to the top of the board. Slip the transformer underneath, and put the capacitor on top of the transformer.

Step3 Attach a ground rod to the wire leading from RFC 2 to the primary coil.

Answer 2

I based this tutorial off of my own experiences building my small tesla coil (battery-powered). I have tried to include information necessary for understanding operation and troubleshooting.

Tesla coils are, essentially, air-cored resonant transformers.

"Transformer" basically means that there are two circuits: A primary and a secondary circuit. The purpose of the primary circuit is to build up a strong magnetic field in a coil of wire that is attached to a circuit. It then cuts off the power to the coil, which causes the EM field to collapse. The secondary circuit has a special coil, too, which is positioned in the center of the primary coil to "catch" the collapsing magnetic field. But because of Faraday's Law of Induction, the collapsing field from the primary coil induces current into the secondary coil that ends up being a higher voltage than the original primary circuit.

"Air-Cored" means that there is no actual electrical connection between the two circuits; energy is transferred between the two coils via EM waves

"resonant" means that, under ideal conditions, the two coils will begin to interact with each other and exchange EM waves at the same frequency, leading to constructive interference and ultimately higher output. It is rare that a homemade coil is able to do this.

Here are the parts of both circuits and how they are made:

The primary circuit

Primary transformer - This is the power source of the system. It usually is a large wall-plug transformer that generates high voltage at a high current. Because it is a transformer, it is essentially a mini-tesla coil in itself. This is a part that you cannot make; you must buy it. Possible sources include the transformers used in neon signs, as well as DC ignition coils with special circuitry attached to pulse them (Neon sign transformers run on AC and thus are already pulsing). If you buy an NST (Neon Sign Transformer), make sure that you purchase an older model that is filled with tar and that is not solid state (ask the guy at the sign store if he has obsolete transformer in the back). A solid state, newer NST will not reach the levels necessary for the coil.

If you want to build a smaller coil like I did, use a DC ignition coil being run from a car battery and pulsed with a relay. A very simple circuit (no soldering required) can be found in my sources section).

Capacitors --- These are, basically, plates of conducting material separated by a dielectric (insulator). They are wired in series with the transformer. When current runs into these, they are able to store up the charge in their plates through an electric field that runs through the dielectric. Capacitors are, in themselves, a project to be taken on and so I cannot go into extreme detail of their design here. Tesla coils require very strong capacitors that usually need to be built. Try researching "Leyden Jars" to get an idea of a basic capacitor design.

Spark Gap --- This is an air gap connected in a parallel circuit to the primary transformer. Once the capacitors have fully charged up, they have built up enough vltage to be able to jump the break in the circuit here. On tesla coils, the capacitors will charge and discharge across the spark gap thousands of times each second.

Primary Coil --- When the capacitors discharge across the spark gap, they momentarily complete a break in the circuit that allows power to flow into this coil. The coil consists of around ten turns of barely insulated heavy gauge copper wire. The coil is wound with a very large diameter (mine is 6 in.) and has supports to keep its shape, but it usually has no inner coil form.

The secondary circuit

Secondary coil --- This is another coil that consists of around a thousand turns of very fine gauge copper wire. It usually must be wound around a coil form (I use PVC pipe) and then insulated with enamel or varnish. It is placed in the center of the primary coil, but it is not electrically connected to it or any other part of the primary circuit. The two coils must be wound in the same direction.

RF ground --- This is the bottom end of the secondary coil. This wire is grounded to insure that high voltages do not hit the primary coil.

Topload --- This is electrically attached to the top end of the secondary coil. It is usually a low-resistance, round metal object that allow spark to fly easily from it. It is optional, since sparks can just jump from the top wire.

Answer 3

To make a simple Tesla coil, you will need basic materials such as a high-voltage power source, copper wire, a capacitor, and a primary and secondary coil. The primary coil creates a magnetic field when energized by the power source, inducing a high voltage in the secondary coil. This high voltage creates arcs of electricity that can be seen as the characteristic sparks of a Tesla coil. Make sure to follow proper safety precautions when working with high voltages.