Disclaimer: As seen previously, this High Voltage Stun Gun is by no means a toy, and any reckless actions with it should be strictly avoided. I bear no responsibility for any harm caused to others or yourself through the use of this device. If you intend to construct it, you must acknowledge and accept these conditions. By following the procedures outlined above, you can steer clear of any potential harm or trouble. Moreover, refrain from carrying it in public spaces or streets if such items are prohibited in your country, and exercise caution when using it in proximity to electronic devices. As a word of wisdom, remember to employ it solely as a deterrent, even against animals.
Circuit diagram
Read before building:
This apparatus generates high-voltage pulses that disrupt muscles and the nervous system, resulting in a state of mental disarray for anyone in contact with it. While it can be employed as a means of defense against aggressive animals or potential attackers, it’s important to note that this device might be prohibited in your state or region. For instance, in the area where I reside, such devices are banned. It poses significant risks to individuals with cardiac issues and can also interfere with electronic equipment, such as pacemakers, due to its emission of radio frequency (RF). It is essential to exercise responsible behavior with this device and refrain from treating it as a toy.
After the introduction let’s pass to the circuit.
The 555 IC is configured as an astable circuit, producing a square wave with adjustable frequency and duty cycle, as indicated by the presence of potentiometers and a diode. This square wave is then directed to control an IRF840 MOSFET. In this case, there’s no need for additional totem pole transistors since the frequency is low, and the IC possesses sufficient current capacity to rapidly charge and discharge the MOSFET gate. Alternatively, a bipolar transistor can be employed instead of the MOSFET, along with a 100-ohm resistor between the 555 IC and the base of the transistor.
Suitable bipolar transistors, such as the BU406, can be used, but smaller BJTs may also suffice. It’s important to ensure that the chosen transistor can handle a continuous current of at least 2 amperes. The inclusion of an inductive kick snubber is unnecessary due to the relatively low power involved, as it is mostly absorbed to charge the tank capacitor. Moreover, since this device operates on battery power, it’s preferable to avoid dissipating power on a resistor and instead allow it to manifest in the form of sparks. Using a snubbing network would result in lower firing rates. For safety purposes, a pushbutton switch should be employed.
Construction of T2:
This part of the process may seem somewhat tedious, but it’s a necessary step since it’s unlikely that these components can be readily obtained from stores. Therefore, we need to construct them ourselves. Here are the materials required: enamel copper wire (either 0.20 mm or 0.125 mm), a ferrite stick, LDPE sheets (0.25 mm). Start by securing the ferrite stick with a layer of LDPE (Low-Density Polyethylene), or as an alternative, use electrical insulating tape, and affix it securely, either by gluing or taping it in place.
Next, create approximately 200-250 windings on the LDPE layer. You may add more windings if the ferrite stick is longer than 1 foot. Afterward, add another LDPE layer, followed by another 200-250 windings, and continue this process until you have achieved around 5-6 layers. This should result in approximately 1000-1400 turns, but you can even add more without detriment to performance, though you should exercise caution to prevent internal arcing, which can damage the component.
Once this is complete, insulate it once more and proceed to place the primary winding, which should consist of 15-20 turns of 1mm wire. This number of windings is sufficient; too many windings can lead to excessive resistance and inductance, resulting in reduced current and a smaller spike in T2 secondary due to a longer rise time. Conversely, too few windings may fail to saturate the core.
I’ve opted for MKP capacitors because of their low Equivalent Series Resistance (ESR) and Equivalent Series Inductance (ESL), which are commonly used in Tesla coils as MMC (Multi Mini Capacitors) capacitors.
For the spark gap, a straightforward setup consists of two wires crossed but not touching each other with a 1 mm gap between them. This gap acts as a voltage-controlled switch, activating when the voltage reaches a level sufficient to ionize the air between the wires, turning it into plasma with relatively low resistance. It’s advisable to encase the spark gap in a small plastic container and fill it with oil to release any trapped bubbles. Be sure to use pure mineral oil, as it doesn’t contain water, avoiding motor oil or frying oil for this purpose.
