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View Full Version : Creating a "simple" EMP

March 23rd, 2006, 10:17 PM
Hey guys, I'm new to this forum, but this post is pretty important, so I'd appreciate some help if it's possible.

I'm a pretty smart 16 year old, taking four Advanced Placement courses among a dozen other things in preparation for college. The subject I'm here to talk about is AP Physics B.

We started the electricity unit a few weeks ago, and my friend Jeff and I convinced our teacher to agree to something: If we could build an EMP, we would both get A+'s for the year. Obviously she makes the final decision, but she's an honest person, and I could use the A+ (I'm averaging about an A right now, but the material is getting pretty tough). I'm not necessarily looking for an easy way out of the course, but showing up the teacher would be nice, and this would be a great way to do so.

So, now my request for all of you: I need help in making an EMP. It need not be tremendously large, it need not be incredibly effective, it just has to work. Is there any relatively easy way to make one? I'm not a fantastic engineering student, but I am willing to put in both time and research, and Jeff and I are capable of getting most necessary materials assuming they're not particularly outrageous.

If it's too complicated for people our age, that's fine too, I just need to know now before I get too involved. Thanks a ton for your help in advance.


March 26th, 2006, 04:10 PM
This is a fairly easily implemented EMWAR solution- the HERF

Chris The Great
March 26th, 2006, 07:39 PM
The most effective EMP from what I have read uses a coil of wire surrounding an explosive charge. A fairly large capacitor bank is discharged into the coil to generate a very powerful magnetic field. At the same time, the tube of HE is detonated at one end, and as the detonation travels down the tube it pushes the potential energy of the magnetic field into a smaller area, as the destroyed coil can no longer store energy. Then it breaks that and all of the energy in the capacitor bank is released instantly as a huge EMP pulse.

The main concerns with such a design is not construction, but getting the timing and everything down. The coil needs to be destroyed when all of the energy is stored as current, not in the capcitor, and the whole system will be resonating since it is an LC resonater. The detonator also needs to fire precisely enough for this, so you'll probably need a slapper detonater, and some way of making sure that everything is timed precisely.
This whole setup will require a very large amount of design work and calculations, I don't think it would be impossible but it would certainly be a challenge.

You could probably buy some high voltage pulse capacitors off ebay, a few hundred joules should be enough for "proof of concept". You'll also need a shield to protect the capacitors from the explosion, so they can be reused, otherwise you'll go through a lot of money really fast.

Lastly, you'll need to make sure your teacher will allow you to use explosives. You probably wouldn't need much for a small scale setup, maybe 30 grams per shot, but still...

You can probably find a much more detailed explanation of the setup I'm talking about on the net, and maybe even have some of the problems I've mentioned solved.

March 26th, 2006, 10:23 PM
I wish my college teachers were that lenient.
Don't tell her who told you the information.

Roguesci or 4HV.ORG
are about the only places I know people know about EMPs.
totse, ehh.. it's not as good as it use to be.

March 27th, 2006, 06:07 AM
Hmmm, I've seen the plans for that explosive EMP. I really doubt that they will let a high school student use that, but....

Why not just use a bank of capacitors to fire into a coil of wire? Wouldn't that generate an electromagnetic field? With enough energy, surely that would be the equivilent of an EMP? And by definition, it would be an EMP, a pulse of electromagnetic radiation.

Or, just after some brief searching have a look here.


Or, here is a site with those plans on the explosive one...

Hope it helps somewhat...

Jacks Complete
March 27th, 2006, 05:02 PM
Any of the plans for "coin shrinkers" should be more than enough to frag anything electrical inside the coil.

March 28th, 2006, 08:11 PM
This is just coming off the top of my head, but how about making an extremely powerful coilgun, usingJust throwing this off the top of my he bare wire and no barrel through the coil. Well, not bare wire, but wire with the insulation filed off on the inside of the coil. As it pulls the slug through the coil, the slug will progressivel short out more of the coil.

No idea if it would work, without further thought, this took less time to think of than to write down, but I figured I would get it out there to see if anyone could take it and turn it into something that makes sense

March 28th, 2006, 11:34 PM

Made from a wire coil and a one-time use camera. How simple is that? :)

March 29th, 2006, 07:28 AM
Has anyone a rough estimate how fast should that shorting out of the coil be to produce good result? Could a "bullet" from air-rifle passing through a coil with stripped wire insulation do the trick?

Jacks Complete
March 30th, 2006, 07:49 AM
The faster the better. Hence using explosives to destroy/switch the coils.

That article is very funny, especially the warnings at the end!

Chris The Great
May 3rd, 2006, 06:52 PM
It's simply a magnetic field and won't generate any substantial emp at all. It might erase your tapes but it won't send out the massive electro-magnetic field that a true EMP creates. A true EMP releases all of it's stored energy at once into the electromagnetic spectrum (ie, radio waves and the like) and doesn't just create a brief magnetic field as the device you have just described would.
Also, you have WAY to much copper wire, the capacitor won't discharge quickly enough... I'd say 50-500 turns would do.

Surprised this got past NBK...

May 3rd, 2006, 10:52 PM
He snuck it in while I was asleep.

But I'm awake now. :)

*RAWR!!...crackcrunch...slish...ploot* ;)