How to make a simple high voltage converter from an ignition coil and relay

There are many interesting DIY electrical projects that require converting low voltage DC to high voltage AC. This may be needed when assembling a homemade plasma lamp, or simply for a spectacular demonstration of a striking spark. The simplest solution for converting the voltage from a conventional 12 V 1.5 A power supply to 10,000 -30,000 V is to use an automotive ignition coil. Its use allows you to assemble a circuit to generate high-voltage voltage in literally a matter of minutes.

Materials:

• automotive ignition coil;
  
• electromagnetic relay;
  
• capacitor 1 µF 250 V;
  
• 12V power supply;
  
• wires, better than car wires.

Converter circuit

An important condition for converting 12 V into high voltage is supplying a pulsating current to the ignition coil. However, the power supply or battery provides constant current, so a relay is required between the electrical source and the coil.An electromagnetic relay senses direct current and releases it in short bursts followed by a short pause. As a result, the coil already receives a pulsating current from the relay, which is what it needs.

The simplest scheme for obtaining high-voltage voltage simply involves supplying power through the wires from the source to the relay, and through it directly further to the coil. However, the principle of operation of the relay is to break the contacts, which is accompanied by the formation of a spark in its body. In this mode, it quickly fails. Its contacts burn out and stop working. To partially reduce the spark strength inside the relay housing, it is necessary to add a 1 µF 250 V capacitor to the circuit, as indicated in the diagram. It is simply soldered with regular solder.

The capacitor is installed between the common power contact of the relay and the normally closed contact. Having made the connection in this way, provided that the relay case is transparent, you can visually see that when voltage is applied from the power supply, the size of the side sparking decreases. In this case, the parameters of the high-voltage current at the output of the secondary winding of the coil will not be affected.

The presence of a capacitor without insulation on the relay is not dangerous, since 10,000V is generated directly inside the ignition coil. Thus, the modified relay does not need special treatment.

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