How to Build a Simple Homemade Tesla Coil That Will Light Up a Bulb Wirelessly


Building a homemade Tesla coil is an exciting project that allows you to wirelessly transfer electricity. With just a few common components, you can construct a working Tesla coil that lights up a lightbulb without any wires connecting them. In this guide, I will walk you through the step-by-step process of building a simple Tesla coil from scratch.

How a Tesla Coil Works

Before starting the project, it helps to understand the basic principles behind a Tesla coil. A Tesla coil is an electrical circuit that uses resonance to generate high voltage alternating current electricity. It consists of two coils - a primary coil and a secondary coil.

The primary coil is connected to a power source and receives low voltage electricity. This electricity passes through a spark gap that acts like an on/off switch, creating pulsed direct current. The rapid on/off switching creates high frequency oscillating current in the primary coil.

The secondary coil is placed above the primary coil. It has significantly more turns of wire than the primary coil. This coil picks up the oscillating current by electromagnetic induction and resonates at the same high frequency. The resonance greatly amplifies the voltage, resulting in an output voltage that can be hundreds of thousands of volts!

This high voltage alternating current generates powerful electric fields that can light up bulbs at a distance without wires. Now let's see how to build one!

Components Required

Here are the components you will need to construct a simple Tesla coil:

Many of these components can be readily sourced from old appliances or electronic devices. The most critical components are the coil and high voltage supply.

Building the Secondary Coil

The secondary coil resonates and steps up the voltage to high levels. Follow these steps to construct it:

  1. Take a PVC pipe around 6 inches in diameter and 24 inches long. This will form the base of the coil.

  2. Wrap several hundred turns of enameled copper wire around the PVC pipe. Leave 4-6 inches of wire at each end for connections.

  3. Use epoxy to glue the wound wire securely to the surface of the pipe.

  4. Attach a small piece of PVC at the top to form a toroid shape. This contains the electromagnetic field.

  5. Seal any gaps in the coil with tape to prevent arcing.

The secondary coil transforms the oscillating current from the primary coil into hundreds of thousands of volts!

Assembling the Primary Coil Circuit

The primary coil circuit consists of the power supply, spark gap, capacitor, and primary coil. Follow these steps to assemble it:

  1. Obtain a neon sign transformer or other high voltage source able to output >10,000 volts AC.

  2. Connect one end of the primary coil to the high voltage supply through a large high voltage capacitor (0.05 μF).

  3. Connect the other end of the primary coil to a spark gap made from screws or wires with an adjustable gap.

  4. Place the primary coil near the base of the secondary coil, making sure there is sufficient clearance to prevent arcing.

  5. Connect the spark gap end to ground to complete the circuit.

This circuit will generate high frequency pulses that induce current in the secondary coil.

Final Assembly and Testing

Follow these remaining steps to finish construction and see your homemade Tesla coil in action:

  1. Mount the secondary coil onto a base made of wood or plastic. Use nylon bolts to prevent shorting.

  2. Position a light bulb or fluorescent tube a few feet away from the top of the secondary coil.

  3. Apply power to the primary coil circuit and adjust the spark gap until you observe large arcs forming on the secondary coil.

  4. Bring your hand or a conductive object near the top of the secondary coil to draw more arcs.

  5. Enjoy watching the light bulb glow brightly without any wires connecting it to the Tesla coil!

  6. Caution: The arcs contain high frequency current and can be dangerous, so maintain a safe distance.

With that, you now have a working DIY Tesla coil capable of wirelessly transmitting electricity across a room! You can enhance it further by adding a solid state spark gap, larger capacitor bank, and higher turns on the secondary coil to generate even larger, more spectacular arcs. Just remember to observe safety precautions when operating high voltage electricity.


Building a Tesla coil at home is an enjoyable way to learn about resonance and experience Nikola Tesla's pioneering technology. With this guide, you should have a functional Tesla coil that uses high frequency electricity to light up bulbs wirelessly. Use caution when operating it and enjoy showcasing the fascinating principles behind this classic electrical invention!