A stun gun is a device designed to generate a high voltage, low current signal, often employed as a weapon to immobilize or weaken a target through electrical shock. However, it’s important to note that stun guns are prohibited in numerous countries due to their potential for causing psychological incapacitation. Typically, a 9V battery is utilized to power these devices. In this project, we will construct a stun gun circuit using a 555 Timer to generate a pulsating current signal, a voltage multiplier comprising a transformer, and a multi-stage setup of voltage doublers employing capacitors and diodes.
- Stun Gun Circuit Operating Principle:
- Stun Gun Circuit Diagram:
- Stun Gun Circuit Design:
- How to Operate Stun Gun Circuit?
- Stun Gun Applications:
- Limitations of Stun Gun Circuit:
Stun Gun Circuit Operating Principle:
The stun gun circuit operates based on the same principle as a conventional stun gun. The frequency of an oscillating signal, generated by a 555 Timer, is dictated by the external passive components linked to the Timer. A step-up transformer transforms the low-current electrical pulses into a high-voltage signal, which is subsequently magnified by a voltage multiplier circuit. This voltage multiplier circuit consists of multiple voltage doubler stages, each featuring two diodes and two capacitors. The voltage doubler circuits employ the Villard doubler method. The quantity of stages directly impacts the output voltage.
Stun Gun Circuit Diagram:
Stun Gun Circuit Design:
In fact, two design phases are required for this project: the astable multivibrator design and the voltage multiplier design.
The initial step in designing the circuit is to determine the desired output voltage. Our objective is to generate a 10KV DC voltage from a 1000V input power source.
The equation yields the result:
Where S represents the number of stages, and Vout = (2Vin + 1.414)S.
To achieve a 10KV voltage, approximately 5 stages of voltage doubling are needed.
To create a 5-stage voltage multiplier circuit that generates a 10KV output voltage, each capacitor should have a voltage rating of at least 1000V, considering the input voltage is approximately 1000V. We opt for a 2500V rating due to the low working frequency, which is in the order of Hertz.
For the astable multivibrator circuit design, we employ a 555 Timer. When designing a 555 Timer in astable mode, it’s necessary to select appropriate passive external components.
We calculate R1 to be approximately 1.44K, R2 to be around 720 Ohms, and C1 to be roughly 10uF, assuming a maximum operating frequency of 50Hz and a duty cycle of 75%. In this example, we use a 2K potentiometer, a 720 ohm resistor, and a 10uF capacitor. For low-frequency operation like this, we utilize an IRF530 MOSFET.
How to Operate Stun Gun Circuit?
The astable action of the 555 Timer begins as soon as the switch S1 is pressed. A low-current pulsing electric signal is generated, which is stepped up to a voltage of roughly 1000V using a step up transformer. A MOSFET switch receives the signal from the Timer.
- Capacitor C3 charges through forward biassed diode D1 during the first positive half cycle. The charge is stored since the capacitor has no discharge channel. At the end of a half cycle, the voltage is equal to the AC input peak value.
- Diode D2 is forward biassed during the negative half cycle, while capacitor C4 charges through C3 and D2. A voltage equal to twice the input AC voltage at the end of the cycle.
- Diode D3 is forward biassed again during the following positive half cycle, and capacitor C5 charges. Diode D4 is forward biassed again during the following half cycle, and capacitor C6 charges. At point 2, a voltage equal to 4 times the input peak voltage is obtained at the end of the cycle.
- 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:
- It can be used for security purpose for individuals from intruders.
- It can be used as protection from animals.
- It can be used as modern warfare equipment.
Limitations of Stun Gun Circuit:
- The circuit is dangerous since it produces high voltage pulses, and it should be built on hardware with extreme caution.
- Because this high voltage, low current signal can send shock waves through the body, upsetting the neurological system, it should not be touched with bare hands.
- Factors like as corona discharge and stray capacitance are not taken into account while constructing the circuit, which could damage the output.
- This circuit should never be used in the company of people who have heart problems.
- It’s actually to build a 9:1000 step up transformer at low frequency, and it’s rather complicated.