I was browsing Aliexpress while i've saw this EMP generator article:

And how it is advertised:

What a nice way to annoy hams :)
When i received the package, i noticed that they removed the transistor info.

Oh common... you can use a 2SC2078, 2SC2166, 2SC2312, 2SC1972, 2SC1972, 2SC1921, 2SC1969, 2SC1945, any of those should be fine, circuit is very primitive.
Here is a close view of the PCB:
Back of the board:

There is almost nothing there, 4 resistors, 3 capas, one npn with erased reference...
Does this worth 18$ ?
Definitely not, and everything can be made from scrap parts...
Small coil and big coil:

Want really to DIY it ? ok here is a reconstruction.
Redraw of the PCB with Eagle:

Draw of a 3D model with SolidWorks to print a case:


Board is 22.90x42.00
Assembling the 45V batteries rig, voltage must be over 30v-45v max, be careful to don't hurt yourself.

3D Printed case result:

Assembling:


Do not hold switch, just click !


Note: Aliexpress take down regularly theses kinds of products.
Does it worth to buy one ?
No, don't, make it yourself.
Another example here on eBay, theses generators are ridiculously overpriced:
There is also tons of fake youtube videos about theses.
Some others fun EMP circuit can be found on my Github, they do the same things.
https://github.com/Xyl2k/EMP-Generators
Xylitol
Breno Juliano "Dot"
mircemk
Jeremy Gilbert
Reiko
Hey @Xylitol, I'm interested on how would you increase the power of the EMP this devices generates?
Would you use different transistors? Or increase the voltage (e.g add more batteries in series)?