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# Stun Gun Circuit

CAUTION: Before going to explain about this concept, we are going to strictly suggesting that DON’T TRY TO IMPLEMENT IT PRACTICALLY AS IT PRODUCES VERY HIGH VOLTAGE.

A stun gun is a gadget used to produce a high voltage, low current signal, used mostly as a weapon to stun or send shock waves to the target with the intention to weaken or paralyze it. However proceeding to design the circuit, it should be kept in mind that in some countries, stun gun is banned. Because, this is actually a lethal weapon which can render a person mentally paralyzed. It is usually powered by a 9V battery. Here, we design a stun gun circuit using a 555 Timer to produce a current fluctuating signal and a voltage multiplier using a transformer and a multiple stage arrangement of voltage doublers using capacitors and diodes.

Outline

## Stun Gun Circuit Operating Principle:

The stun gun circuit is based on the principle behind a conventional stun gun. A 555 Timer is used to produce an oscillating signal of frequency determined by the external passive elements connected to the Timer. These low current electric pulses are fed to a step up transformer to produce a high volt signal, which is further increased by a voltage multiplier circuit. The voltage multiplier circuit consists of multiple stages of voltage doubler each consisting of two diodes and two capacitors. The voltage doubler circuits are based on Villard doubler method. Output voltage is directly proportional to the number of stages.

## Stun Gun Circuit Diagram:

#### Stun Gun Circuit Design:

Actually, here we require two phases of designing – The astable multivibrator design and voltage multiplier design.

Designing the circuit requires pioneer step of deciding the output voltage . Here our requirement is to generate a 10KV DC voltage from 1000V input.

From the equation,

Vout = (2Vin + 1.414)S, where S is the number of stages.

To obtain voltage of 10KV, about 5 stages of voltage doubler would be required.

Here we design a 5 stage voltage multiplier circuit generating an output voltage of 10KV.  Since input voltage is around 1000v, each capacitor should have a voltage rating of atleast 1000V. Since here operating frequency is low, of the order of Hertz, we require a 2500V, 10mF.

For designing the astable multivibrator circuit, we select a 555 Timer. To design a 555 Timer in astable mode, passive external components need to be selected.

Assuming a maximum operating frequency of 50Hz and a duty cycle of 75%, we calculate R1 to be around 1.44K, R2 around 720 Ohms and C1 around 10uF. Here we select a 2K potentiometer, 720 ohm resistor and 10uF capacitor. Since this is a low frequency operation, a MOSFET IRF530 is used.

Also Read the Interesting Concept – Electronic Toy Piano using 555 Timer IC

#### How to Operate Stun Gun Circuit?

As soon as the switch S1 is pressed, the astable operation of 555 Timer starts. A pulsating electric signal of low current is produced, which is stepped up using a step up transformer, to a voltage of around 1000V. The signal from the Timer is fed through a MOSFET switch.

1. During first positive half cycle, capacitor C3 charges through diode D1, which is forward biased. Since the capacitor has no discharge path, it stores the charge. This produces a voltage equal to the AC input peak value at the end of half cycle.
2. During negative half cycle, diode D2 is forward biased and capacitor C4 charges through C3 and D2. At the end of the cycle a voltage equal to double the input AC voltage.
3. Again during next positive half cycle, diode D3 is forward biased and capacitor C5 charges. Again during next half cycle, diode D4 is forward biased and capacitor C6 charges. At the end of the cycle, a voltage equal to 4 times the input peak voltage is obtained at point 2.
4. The same procedure applies for other two stages and finally a voltage equal to 10 times the input voltage is obtained at point 5.

#### Stun Gun Applications:

1. It can be used for security purpose for individuals from intruders.
2. It can be used as protection from animals.
3. It can be used as modern warfare equipment.
##### Limitations of Stun Gun Circuit:
1. Since this involves high voltage pulse production, the circuit is hazardous and should be implemented on hardware with uttermost care and precaution.
2. One should not touch the output with bare hands as this high voltage, low current signal can send shock waves through the body, disrupting the nervous system.
3. While designing the circuit, factors like corona discharge, stray capacitance are not taken into account, which may affect the output.
4. This circuit should never be used in presence of persons with cardiac issues.
5. It is actually to get a 9:1000 step up transformer at low frequency and its construction is quite complex.

### 22 Responses

1. Josh S. says:

I would like to say that I am a just student who is part way through Circuits 1 , but it seems to me that there are a ton of improvements that could be made to this project.

The 10:1 transformer is a step down, not step up, and even if it were a 1:10; it would only put out 90V, not 500V. The voltage multiplier equation does not look correct either, but I am not going to specifically attack that one because it can easily be looked up. Additionally, the 75% duty cycle and low frequency seem very wasteful in this project since the MOSFET can easily handle the higher frequencies and the capacitors will have a lower impedance at such frequencies allowing a greater output current. If the low frequency was chosen because of an iron core transformer, it should be replaced with a ferrite core, because it is: more efficient, can handle higher frequencies, is lighter, and more compact for a stun gun. Finally, the transformer does not respond more strongly to a longer duty cycle after a point, so there is definitely wasted input there also. The accompanying paragraphs with this diagram are also not very well written and full of small errors. However, I do apologize if English was not the posters native language.

Thanks for listening to my complaints.

1. Nit Krish says:

Hey Josh myself Nit Krish and am working on a project and i would like to be in touch with you . I would be delighted if you could mail me at nit000krish@outlook.in .

2. Arthur says:

What type of transformer is used? What is the turn ratio of the transformer?

3. Johnny says:

No pictoral diagram?

4. tamilselvi says:

its working well…but we have tested in human (dheivam)

1. v.praneeth says:

the circuit of stun gun is really working or not?
there is any modifications?
please tell me,i want to work on this project

2. geeth says:

yeah…its Working done recently

5. Rahul Ghose says:

Hi there living in sweden and need a more effectiv how much can puch the 555 timer on R1 and R2 Or any other chematic with higher Milli amps to boost up voltage on ?
want to use ” 5 voltage reloading battery pack with 6000mA/h maximum output is 5v dc 2Amps to load Android Phones .

The Police And Goverment dont help Forigners from Bullies and Criminals anymore and they are wery much on heavy drugs , I need at least 1.5 000Kv as the modern stun guns goes up to 4.5 000Kv
Is possible to cool down the 555 timerbody with alluminium cooling , ???

6. Krushnakant says:

Hi I AmetA Krushnakant & I am also work forthis project so give me a report plz
On gmail

7. Danny Andrion says:

Hello there!,
I tried to experiment with the circuit diagram as illustrated above. It works for me.
I didn’t load the diodes and and capacitors yet, only up to transformer. The frequency
I accidentally used in 555 timer output was 180 Hz. Transformer was 1 Amp, 12volts input to 220volts
output, step-up. The moment I heard a whistling sound, I believed it worked. I measure the output of the transformer, it’s 1000 volts AC. Need heatsink in the mosfet to avoid over heating.

Danny A.

8. oscar says:

with this circuit, could i Kill a mouse?

1. Da Wae says:

it depends on the size of the mouse.

2. Umair says:

Well did it kill a mouse? Let me know.

9. Ouss says:

What is the role of transformer in this circuit?

10. Yuvam Bhateja says:

Please tell, what is the function of mosfet ?
I tried to make it without it but it didn’t work !!

11. Phil171 says:

If you don’t know what is the role of transformer or what is the function of MOSFET in this circuit, I propose to you to read first phrases on “How to Operate Stun Gun Circuit?” below… It is explained.
I agree with Josh S, this circuit is not really optimized but can works.

12. debela genale says:

please tell me why transformer is being used

1. Alfons says:

To step up the Voltage

13. Stanley says:

Iam intending to implement the project plz help me with the block diagram and the ràting of the circuit in terms of voltage ,current and power

14. J Hughes says:

The quickest way to make a shock device is to take an Electric Mosquito Swatter, remove the head with the mesh and then you are ready for the next Break & Enter Artist by touching him with the exposed wires from the handle.