EMP notworking,i followed every steps on tutorial. Can you find where goes wrong?

Tutorial i follow: http://teslaundmehr.de/2015/12/05/emp-jammer/

Componet :

single 18650 battery

3v to 40v boost convert 

1.2mm coil

2sc2078 transistor

47 and 220 pf capacitor

10k resistor

i can hear some weak sparkish noise from top of the coil, and transistor goes hot too. but just nothing happens to lightbulb and calculator

April 18 update: i connected the losing end( pic10). but still nothing, any other thought ?
new diagram at pic 8

i'll keep updating as i soldering componets using no wire

April 22 update: it worked, with a other small test coil i made, (pic 1,3,4)i swaped several transistors made sure only problem was the coil. where goes wrong with the bigger coil (pic2,5) ? 

also, i've switched winding lead on big coil, still goes nothing (small one works with either way). i was guessing perhaps i've made too many turns on L1 somehow changed behavior of coil

(another interesting phenonenal i've noticed is as you stick an iron cord inside coil, EMP field despairing rapidly to 0. which is bit different then i learned in high school)

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Jack A Lopez3 months ago

I forgot to mention: For these oscillator circuits that use a transformer with one of the windings providing a feedback signal, and the oscillator will not start.

Often it is just because one of the windings is "upside down". In other words, switching the leads on one of the windings, will make it work.

Or at least that was true of the Joule Thief circuit,


The circuit for that one... was not the same, but somewhat similar to the circuit you have linked to.

Also, I was going to mention, I noticed the author you linked to, Teslaundmehr (Tesla and me?) has a Youtube channel, and while looking at one of his videos I noticed there seem to be a number of similar videos describing the same jammer circuit, like this one,

This one seems easier for me to follow, in part because my native language is English, and I do not understand German. Also I think this video, by TheTechGuru, is showing me some more clear images of what the transformer geometry looks like.

It seems to me that this circuit is like, folklore. I mean there are a lot of people copying, and re-telling this story, but it is unclear to me, at present, who is the original author of this circuit, and more importantly, which of these derivative works are actually good, working, designs, and which are bad not-so-good designs.

Also I was going to mention, I just don't get why the windings on this air-core transformer are arranged at right angles to each other. My intuition says that would not make a good transformer, but I dunno maybe the coupling between these two windings are supposed to be weak.

Anyway, I suggest trying to search for the other versions of this project that are out there, because possibly that will maybe make it more clear, just by looking at it from several different perspectives.

EthanY (author)  Jack A Lopez3 months ago

Thanks! i've soldered components togther and wired a small coil just for easy comparement, it worked. but i'm stuck with can't get the original coil working. any suggestions?

(updated pic on topic)

Well, the geometry of the two coils, that you have wound, do not look like the coils wound by TeslaUndMehr or by TheTechGuru.

Some features of their coils:

The secondary winding, the one connected to the transistor's base, is short and fat. That is to say it has length shorter than, or about the same size as its average diameter.

The primary winding is long and thin, and straight, with a length about the same as the diameter of the secondary winding.

In contrast, for the coils you are winding:

Your secondary winding is long and skinny. That is to say its length is larger than its average diameter.

Your primary winding is long and thin, but not straight. For some reason, you are twisting your primary winding into a circle, like a torus, and that is something very different from what TeslaUndMehr and TheTechGuru are doing with their primary coils.

I guess, in summary, all I am suggesting is that you try to make your coils have the same shape as the ones from the examples you say that you're following.

iceng3 months ago

You need as short as possible wiring and

much heavier diameter gauge (smaller_numbers) at least as large as the coil..

Click the pic..

Jack A Lopez3 months ago

There was one other thing I was going to mention regarding clip leads.

If you bought the cheap kind, for these the actual connection from one alligator clip to the other is often, not well connected. And you can discover a bad, or intermittently connected, clip lead by testing it with ohmmeter (or mulitmeter in resistance measuring mode)

Moreover the place where a cheap clip lead is not well connected is under that little rubber hood where the alligator clip is crimped to the wire.

Fortunately there is an easy fix for this. Simply slide back that rubber hoodie thing, and re-do that crimped connection with a soldered connection. Also re-do the crimp, so it is crimped over the insulated part of the wire, holding it securely in place.


rubber hoodie thing a ma bob, Ha Ha ;-)


Well I knew it was some kind of clothing analogy. Although, I would have guessed, "sleve", or "jacket", before I guessed "boot".

I suppose Wikipedia is also calling it, "boot",


But the clip thing looks like an alligator head. It even has "jaws". What kind of clothing covers a head? Answer: a hood, or hoodie.

It makes more sense than calling it a "boot", which is clothing that covers a foot.

I mean, boots are like gloves you wear on your feet instead of on your hands.

OK where do you wear rubber? And keep it clean:-)

I dunno. Dishwashing gloves? The soapy water helps keep them clean.

;-) I must be older than you.

EthanY (author)  Jack A Lopez3 months ago

Thanks,i solderd yellow wire to crocodile clip, indeed it looks like it isnt oscillating since still nothing happens. i'll let you know results after i solderd components with no wire


Jack A Lopez3 months ago

I am going to guess the reason your circuit does not work is because you have it connected together with long clip leads.

At high frequencies, long wires become unintended inductors and capacitors, and those might be changing the character of your circuit.

I am not sure how this circuit works exactly, but I think we are relying on some sort of feedback from the from the secondary winding (labeled L2) of that transformer, since one side of L2 is connected to the base of the transistor.

I mean, imagine what the circuit would look like with that wire, from base of transistor to L2, disconnected. The only current going into the base of the transistor would just be that coming through that 10K resistor, and the transistor would just turn on, and stay on.

And that kind of seems like what is happening to your circuit. Transistor just turns solid on, without oscillating.