EMP Generator

Enclosure

I designed the enclosure myself using SolidWorks and 3D printed it on my own Flashforge 3D printer with PLA. The enclosure contains holes on the sides for two buttons - both have to be pressed in order to activate the EMP, kind of like how a lighter has two switches so you don’t accidentally light the wrong birthday candle. Inside it has some structures to screw in place the battery and other components, as well as two divots on each shell to hold magnets, allowing the EMP generator to be magnetically sealed while keeping its shell easily separable. I used magnets since I wanted it to be pretty easy to open up the device and troubleshoot whatever was inside, and I didn’t want ugly screws ruining the smooth exterior.

Electrical System

Inside we have a 3.7V LiPo battery, two 1nF capacitors in series (each one is rated for ~25kV, so in series we can handle ~50kV), a high-voltage transformer that can output a maximum of 1.5A at 50kV, and a few turns of copper wire around the bottom to create an inductor. There’s also a spark gap formed by putting electrical tape over two strands of wire to hold them about 5mm apart.

Using the diagram below as a reference, the idea is that the high voltage transformer turns up the incoming 3.7V from the battery to about 50kV at its output (in layman’s terms, a lot of volts). This will charge up the capacitor, creating a 50,000 volt difference between ground and one end of the capacitor. By placing the wires in the spark gap close enough together, we can get them just far apart enough that the high voltage is capable of ionizing the air and arcing across. This arc is demonstrated in the video, and while you can’t tell just by watching, it smells really bad. The arc will cause the capacitor to discharge extremely quickly through the inductor - by Lenz’s law, inductors resist a change in current by creating an opposing magnetic field, so the huge change in current will result in a huge magnetic field, resulting in an even larger electric field (the “electromagnetic pulse”). This even larger electric field then induces current spikes in nearby electronics, which can fry the internal circuitry if they’re not equipped to handle current surges.