I made this by winding lots of 40SWG wire around a PVC pipe and then covering it in electrical tape. I then used some 2.5mm2 house wiring cable as a primary coil and pulsed 1.2kV DC using one of those hand-held bug zappers through a spark gap and a timing capacitor of 0.047uF and the result is a high voltage spark on the output.

How big is the spark?
sorry i did not see the ferrite core i am highly intrested in this project
Please see the photos page for this project for more information on how I built it. <a href="https://www.instructables.com/id/Homemade-high-voltage-transformer/">https://www.instructables.com/id/Homemade-high-voltage-transformer/</a><br> as this is just a video.<br>
i thought the core must be magnetic?
The core must be ferrous, which it is. When it is used as a core it magnetises and de-magnetises each time there is current going through the primary coil.<br><br>Basically it switches between being magnetic and non-magnetic.
Here are some more photos of it being made https://www.instructables.com/id/Homemade-high-voltage-transformer/
Thanks. I am going to add some more photos at some point and a better explanation.

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Bio: Me on YouTube youtube.com/Alex1M6
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