How do you make an Electro Magnetic Pulse Device?

I would like to make and EMP device to blow an RFID.
I understand that it is a capacitor and a coil.  And that you charge the capacitor up and then discharge it through the coil.  But what size and voltage should the capacitor be, and at what what voltage do you charge it and how thick does the wire need to be?

Is it all about the voltage of the cap (12 volt or 400 volt)  or is it more about the size of the cap?


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rickharris5 years ago
search for EMP this is asked often.
lemonie5 years ago

Use a microwave oven instead, much easier.

much deadlier.
There are legends of people building such mini-EMP devices from a modified camera flash circuit,  and I found this video:

Building a RFID Zapper - Hacking a Disposable Camera

Regarding the question of what is "all about"?  Is is more about voltage or size of cap?  The answer is, it is both.  The capacitor serves as a means for storing energy, and the quantity of energy stored is U= 0.5*C*V2, and as you can see, both voltage and capacitance are in that equation.

The other part of the trick, besides storing up electrical energy, is to release that energy quickly.  That way you get high peak power.  Recall power is the time derivative of energy. 

One of the most interesting ways I have seen to get fast, solid, high-current,  switching, without the use of a SCR, or thyristor, or spark gap switch, involves using a rat-trap.  You kind of have to see this one to believe it. Here:
I guess I might be in over my head with this because i have a tiny mosfet trasformer 45volts ( 5 -9v batterys) a resistor value of 3.4k and the solid copper wire but I am not getting anywhere because i dont know the values of the 4 in total capacitors. 1 connecting the emitter and base and the 3 wired together from the 3rd pin on the mosfet circuit and the copper coils.
I forgot to mention: coil gun, rail gun, electromagnetic can crusher, or anything using a capacitor bank as its power source, these all fall under the category of pulsed power.

Searches for any of those topics will lead you towards circuits that may be useful for generating homemade EMP.
Aussie14 (author) 5 years ago
Thanks guys. I suspected that it was about how quick it can be delivered. I tried the cap I have with a few loops of really heavy guage wire and again with thin wire. The "crack" was much bigger with the thick wire. The one that I have at the moment is 40 volts. I'll start looking for a higher voltage. Cheers to all.
rickharris5 years ago
Sledge hammer works as well.