High Voltage Stun Gun
Read before building:
This device produces high voltage pulses discrupting muscles and nervous
sYstem, leaving anyone who touches it in a state of menthal confusion.
Can be used agains ferocious animals or attackers, BUT REMEMBER, this
device may be illegal in your state (for eg where I live, these devices
are banned). It is quite dangeros for peoples experiencing cardiac
problems, and for electronic equipment (like peacemakers), since it
generates some RF. Don't attept irresponsible actions with this device,
it is not a toy.
After the introduction let's pass to the circuit.
The 555 IC is wired as a astable to produce square wave with adjustable
freq and duty cycle (notice the potentiomenters and diode). This square
wave is feed to a IRF840 Mosfet (no need of totem transistors since freq
is low and the IC has enough current capability to rapidly
charge/discharge the gate). As a substitute of the mosfet, a bipolar
transistor can be used (and a 100ohm resistor between 555 and base of
the transistor). Valid BJT can be BU406, but also smaller BJT can be ok,
keep in mind that it must handle at least 2A continuous. The inductive
kick snubber isn't needed because the power is low and it is almost
totally adsorbed to charge the tank capacitor, in addition since this
device is battery operated we don't want to dissipate the power on a
resistor but we want it in sparks. With a snubbing network you will
experience lower firing rates. USE A PUSHBUTTON SWITCH FOR SAFETY
Construction of T2: this is the real boring part. Since it is unlikely
to find it in shops we need to build them. Materials needed: enamel
copper wire (0,20 mm or 0,125 mm), ferrite stick, LDPE sheets (0,25 mm).
Secure the ferrite stick with a layer of ldpe (polyethilene, as a
substiture use electric insulating tape) and glue it (or tape it) Place
200-250 windings on the ldpe (even more windings if the stick is more
than 1'), another ldpe layer, another 200-250 windings and so on to
finally have 5-6 layers (approx 1000-1400 turns but even more doesn't
hurt performance, but be careful for internar arcing that will ruin it).
Insulate it again and place the primary winding, 15-20 turns of 1mm
wire are just ok, too much windings (too mush resistance and inductance)
will lead to smaller current and smaller spike in T2 secondary because
of lower rise time,and too few will not saturate the core. I chosen MKP
capacitors because they have low ESR and ESL (they are widely used in
tesla coils as mmc capacitors).
The spark gap can be simple two crossed (but not touching) 1 mm spaced
wires. It acts as a voltage controlled switch, firing when
the voltage is enough to ionize the air between them (turning it to
plasma with small resistance). Keep in mind that it would
be wise do place it into a small plastic container and fill with oil
letting bubbles out (don't use motor oir or frying oil
but pure mineral oil which has no water in it.
Disclaimer: As i have seen before, IT IS NOT A TOY, DON'T DO ANYTHING
STUPID WITH IT. I DON'T ACCEPT ANY RESPONSIBILITY OF DAMAGES DONE TO
OTHER PEOPLE OR YOURSELF WITH THIS DEVICE. IF YOU WANT TO BUILD IT YOU
MUST ACCEPT THIS CONDITION. Using the procedures described above would
prevent you from any damages/troubles. Don't carry it in streets or
public places if they are banned in your country, and don't use it near
electronic devices. As the wise man says use it like a deterrent, even
Also check the conversation about this project at the community. Post
you questions here.