Introduction: Variable Voltage Ignition Coil Power Supply

This instructable deals with the creation of a very simple high voltage power supply using a car ignition coil. Please take care if you are going to build this as the voltages exceed 30,000. Also do not attempt this project unless you know the dangers of high voltage. This supply can be used for tesla coils and with the right component values produce an arc like a neon sign transformer.

Step 1: Parts

First of all your going to need:
- A gluegun
- A car ignition coil
- A light dimmer (400w+)
- A capacitor with a voltage rating of around 600v and a capitance between 0.1 and 30 microfarads
- some 2 core mains cable with a flug
- Sunflower oil
- Some bolts
- Some insulated wire (stripped mains cable will do)
- A drill
- Zipties
- A plastic box ( I used a 3Litre box from maplins)

Step 2: Putting It Together

This step is fairly simple.

Live wire:
You will need to wire the live input from the mains to the dimmer and out again.
Then from the dimmer the live wire goes to the capacitor ( make sure its the + terminal if it is a polarised capacitor)
After the capacitor the live goes to the + terminal on the ignition coil

Neutral wire:
This wire goes straignt from the mains to the - terminal on the ignition coil
Also this wire will have to be extended past the ignition coil so it is attached to a bolt through your case. Basically this serves as the high voltage return for the high voltage secondary output.

Middle terminal on ignition coil:
This terminal is high voltage positive and will be arcing to the - of the primary. Run  a wire from the middle of this terminal to a bolt in the case.

This whole setup will need to be submerged in oil to prevent arc overs. Transformer oil is expensive so I used sunflower oil ( £3 for 3litres in Tescos) and it works just as well. Do NOT use motor oil as this is volatile and might explode.

Use zipties to secure your apparatus and cover the drill holes with hot glue to prevent the oil leaking out.

For my power supplyI used a 400w dimmer switch, a 0.1microfarad MOT capacitor.

Step 3: Results

Here are some pics of the output. My camera is crap but this at max ( dimmer turned all the way up) produces around 40KV.