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509 ARMY BASE WORKSHOP

INDUSTRIAL TRAINING PROJECT

PROJECT NAME

Electric Stun Gun

Submitted to: Submitted by:

Commandant & MD Manu Khandelwal

509 Army Base Workshop, Rohit Kumar

Agra Kalpagya Goyal

Devkaran

Piyush Kumar

Project done at 509 Army base workshop, Agra

{ISO 9001:2008 Certified}

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ACKNOWLEDGEMENT

We must first of all, express our heartliest gratitude to ARMY BASE WORKSHOP 509 for

providing us such a platform for implementing the ideas in our mind and also a special great

full thanks to Col. M.C. KUTHARI (OIC GEGP).

We would also like to thank Mr. O.P GAUTAM (TCM) who supported us to complete the

project, and gave us all the guidance to complete this project.

We would also like to thank GE Group for supporting us and providing us the platform to

complete this subject. We feel profound pleasure in bringing out this project report for which

we have to go from pillar to post to make it reality. Today when our endeavour has reached,

we look back in mute gratitude to one and all without whose help, this reality would have

remained a dream.

1. Manu Khandelwal

2. Rohit Kumar

3. Piyush Kumar

4. Devkaran

5. Kalpagya Goyal

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ABSTRACT

Electric stun guns have been developed as less-lethal devices that law enforcement officers

can use to control potentially violent subjects, as an alternative to using firearms. These

devices apply high voltage, low amperage and pulsatile electric shocks to the subject, which

causes involuntary skeletal muscle contraction and renders the subject unable to further resist.

In field use of these devices, the electric shock is often applied to the thorax, which raises the

issue of cardiac safety of these devices. An important determinant of the cardiac safety of

these devices is their electrical output. Here the outputs of three commercially available

electric stun guns were evaluated with a resistive load and in a human-sized animal model.

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TABLE OF CONTENTS

S. No Contents Page No.

1 Acknowledgement 2

2 Abstract 3

3 Table of Contents 4

4 List of Figures 5

5 Introduction 6

6 History of Stun Gun 7

7 Circuit Diagram of Stun Gun 7

8 Principle of Operation 8

9 Description of Material Used in Stun

Gun

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10

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Timer and Circuit Details

Modes of Operation of 555 Timer

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12 Types/Varieties of Stun Gun 23

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15

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Stun Gun Design and Operation

Testing and Caution During Operation

Advantages & Disadvantages

Applications

References

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Lists of Figures

S. No. Figure Page No.

1 Circuit Diagram of Stun Gun 7

2 Resistor 11

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4

5

6

7

8

9

10

11

12

13

14

15

16

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Simple Transformer Assembly

Symbol of Polar Capacitor

Electrolytic Capacitor

Symbol of Non-Polar Capacitor

Shape of Diode

555 Timer Pins

MOSFET

Terminals of MOSFET

555 Timer

Pin Details of 555 Timer

5555 Timer Pin Connections

Standard 555 A-Stable Circuit

A Concealable Weapon Shaped and Sized like a

lipstick tube

Electric Cattle Prod from the 1950’s

Circuit Diagram of Stun Gun

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INTRODUCTION

The electric stun gun is a modern, portable, personal-protection appliance. It generates

high potential energy to ward off vicious animals or other attackers. It is an aid to help

escape from a potentially dangerous situation. The device develops about 200,000 volts.

Higher voltages attained by adding additional multiplier stages, but it should be noted that

those stage will also increase the overall size of the unit. The stun is very compact, being

built into a small plastic case. It is powered by a single 9-volt battery, either NiCad or

alkaline. The high voltage is applied to two electrodes which require only light contact to

be effective. When touched with the tazer, the victim will receive a stunning, but non-

lethal jolt of electricity that will usually discourage any further encounters. The electric

stun gun tazer is a power supply which consists of a micro-size regenerative

amplifier/oscillator coupled to an energy multiplier section. It should not be confused

with a cheap induction-type cattle prods. The tazer is more versatile than other high-

voltage stun devices currently being sold. Those devices are basically high-voltage, AC

generators which jam the nervous system. However, the tazer may be used for heating

and burning applications, or anywhere a high voltage DC supply is required.

An electric shock weapon is an incapacitant weapon used for incapacitating a person by

administering electric shock aimed at disrupting superficial muscle functions and/or

causing pain without significantly hurting the subject.

Multiple types of these devices exist differing by the mode of use. Stun guns, batons (or

prods), and belts administer an electric shock by direct contact, whereas Tasers

(conducted electrical weapons, CEW) fire projectiles that administer the shock through

thin flexible wires. Long-range electroshock projectiles, which can be fired from ordinary

shotguns and do not need the wires, have been developed as well.

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History of Stun Gun

Jack Cover, a NASA researcher, began developing the Taser in 1969. By 1974, Cover had

completed the device, which he named after his childhood hero Tom Swift ("Thomas A.

Swift's electric rifle").The Taser Public Defender used gunpowder as its propellant, which led

the Bureau of Alcohol, Tobacco and Firearms to classify it as a firearm in 1976. John Cover's

patent was adapted by Nova Technologies in 1983 for the Nova XR-5000, their first non-

projectile hand-held style stun gun. The XR-5000 design was widely copied as the source for

the compact handheld stun gun used today.

Circuit Diagram of Stun Gun

Fig.1 Circuit Diagram of Stun Gun

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Principle of Operation

Electroshock weapon technology uses a temporary high-voltage, low-current electrical

discharge to override the body's muscle-triggering mechanisms. The recipient is immobilized

via two metal probes connected via wires to the electroshock device. The recipient feels pain,

and can be momentarily paralyzed while an electric current is being applied. It is reported

that applying electroshock devices to more sensitive parts of the body is even more painful.

The maximum effective areas for stun gun usage are upper shoulder, below the rib cage, and

the upper hip. High voltages are used, but because most devices use a non-lethal current,

death does not usually occur. The resulting "shock" is caused by muscles twitching

uncontrollably, appearing as muscle spasms.

The internal circuits of most electroshock weapons are fairly simple, based on either an

oscillator, resonant circuit (a power inverter), and step-up transformer or a diodecapacitor

voltage multiplier to achieve an alternating high-voltage discharge or a continuous direct-

current discharge. It may be powered by one or more batteries depending on manufacturer

and model. Output voltage is claimed to be in the range of 100 V up to 6 KV; current

intensity output is claimed to be in the range of 100 to 500 mA; individual impulse duration

is claimed to be in the range of 10 to 100 µs (microseconds); frequency of impulse is claimed

to be in the range of 2 to 40 Hz; electrical charge delivered is claimed to be in the range of 15

to 500 µC (micro-Coulomb); energy delivered is claimed to be in the range of 0.9 to 10J. The

output current upon contact with the target will depend on various factors such as target's

resistance, skin type, moisture, bodily salinity, clothing, the electroshock weapon's internal

circuitry, discharge waveform, and battery conditions.

Manufacturer’s instructions and manuals shipped with the products state that a half-second

shock duration will cause intense pain and muscle contractions, startling most people greatly.

Two to three seconds will often cause the recipient to become dazed and drop to the ground,

and over three seconds will usually completely disorient and drop the recipient for at least

several seconds. taser International warns law enforcement agencies that "prolonged or

continuous exposure(s) to the taser device’s electrical charge" may lead to medical risks such

as cumulative exhaustion and breathing impairment.

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Because there was no automatic stop on older model Taser guns, many officers have used it

repeatedly or for a prolonged period of time, thus potentially contributing to suspects’ injuries

or death. The current X26 model automatically stops five seconds after the trigger is

depressed and then the trigger must be depressed again to send another "shock". The trigger

can be held down continuously for a longer shock or the device can be switched off before

the full five seconds have elapsed.

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Description of Material Used in Stun Gun

Material Used in Stun Gun

1. 555 timer

2. 8pin chip socket

3. A 9:1000 ferrite core audio transformer

4. 10uF capacitor

5. 0.1uF capacitor

6. 10 x BA159 diodes ( they are faster than the 1N4007, meaning better performance)

7. 10x 3nF, 1200V ceramic capacitors.

8. Neon lamp

9. IRF 530 MOSFET

10. 680Ohm resistor

11. 2kOhm potentiometer (for more accuracy)

12. IR LED

13. 2x 9V batteries

14. Micro switch

15. Printed Circuit Board

16. Connecting wires

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Description of Material Used

Resistor:

The flow of charge (or current) through any material, encounters an opposing force similar in

many respect to mechanical friction. This opposing force is called resistance of the material.

It is measured in ohms. In some electric circuits resistance is deliberately introduced in the

form of the resistor.

Resistors are of following types:

1. Wire wound resistors.

2. Carbon resistors.

3. Metal film resistors.

Fig.2 Resistor

Transformer

Transformer works on the principle of mutual inductance. We know that if two coils or

windings are placed on the core of iron, and if we pass alternating current in one winding,

back emf or induced voltage is produced in the second winding. We know that alternating

current always changes with the time. So if we apply AC voltage across one winding, a

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voltage will be induced in the other winding. Transformer works on this same principle. It

is made of two windings wound around the same core of iron. The winding to which AC

voltage is applied is called primary winding. The other winding is called as secondary

winding.

Transformers are of two types Step Up transformer and Step Down transformer.

Fig.3 Simple Transformer Assembly

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Capacitors

A capacitor can store charge, and its capacity to store charge is called capacitance. Capacitors

consist of two conducting plates, separated by an insulating material (known as dielectric).

The two plates are joined with two leads. The dielectric could be air, mica, paper, ceramic,

polyester, polystyrene, etc. This dielectric gives name to the capacitor. Like paper capacitor,

mica capacitor etc.

Capacitors are of two Types Fixed and variable capacitor. Fixed types of capacitor are

further of two types:-

1. Polar Capacitor

2. Non Polar Capacitor

Fig.4 Symbol of Polar Capacitor

Fig.5 Electrolytic Capacitor

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Fig.6 Symbol of Non-Polar Capacitor

Diode

Diodes are semiconductor devices which might be described as passing current in one

direction only. Diodes have two terminals, an anode and a cathode. The cathode is

always identified by a dot, ring or some other mark. Diode is a unidirectional device. In

this current flows only one direction.

Fig.7 Shape of Diode

Diodes can be used as voltage regulators, tuning devices in RF tuned circuits, frequency

multiplying devices in RF circuits, mixing devices in RF circuits, switching applications or

can be used to make logic decisions in digital circuits. There are also diodes which emit

"light", of course these are known as light-emitting-diodes or LED's.

a rectifying diode of the 1N4001-07 ( 1A) type or even one of the high power, high

current stud mounting types. You will notice the straight bar end has the letter "k", this

denotes the "cathode" while the "a" denotes anode. Current can only flow from anode to

cathode and not in the reverse direction, hence the "arrow" appearance. This is one very

important property of diodes.

The principal early application of diodes was in rectifying 50 / 60 Hz AC mains to raw

DC which was later smoothed by choke transformers and / or capacitors. This procedure

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is still carried out today and a number of rectifying schemes for diodes have evolved

half wave, full wave and bridge, full wave and bridge rectifiers.

555 Timer

The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse

generation, and oscillator applications. The 555 can be used to provide time delays, as

an oscillator, and as a flip-flop element. Derivatives provide up to four timing circuits in

one package. It is an 8pin silicon chip. In a-stable mode this is used to produce low

frequency oscillations.

Fig.8 555 Timer Pins

MOSFET

The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS

FET) is a type of transistor used for amplifying or switching electronic signals. In the

stun gun project MOSFET IRF530 is used for the low frequency operation.

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Fig.9 MOSFET

Although the MOSFET is a four-terminal device with source (S), gate (G), drain (D), and

body (B) terminals, the body (or substrate) of the MOSFET is often connected to the source

terminal, making it a three-terminal device like other field-effect transistors. Because these

two terminals are normally connected to each other (short-circuited) internally, only three

terminals appear in electrical diagrams. The MOSFET is by far the most common transistor

in both digital and analog circuits, though the bipolar junction transistor was at one time

much more common.

Fig.10 Terminals of MOSFET

The main advantage of a MOSFET transistor over a regular transistor is that it requires

very little current to turn on (less than 1mA), while delivering a much higher current to

a load (10 to 50A or more). However, the MOSFET requires a higher gate voltage (3-

4V) to turn on.

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Timer and Circuit Details

The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse

generation, and oscillator applications. The 555 can be used to provide time delays, as

an oscillator, and as a flip-flop element. Derivatives provide up to four timing circuits in

one package. It is an 8pin silicon chip. In a-stable mode this is used to produce low

frequency oscillations.

Fig.11 555 Timer

Introduced in 1971 by American company Signe-tics, the 555 is still in widespread use

due to its ease of use, low price, and stability. It is now made by many companies in the

original bipolar and also in low-power CMOS types. As of 2003, it was estimated that 1

billion units are manufactured every year.

Depending on the manufacturer, the standard 555 package includes 25 transistors, 2

diodes and 15 resistors on a silicon chip installed in an 8-pin mini dual-in-line package

(DIP-8).

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Fig.12 Pin Details of 555 Timer

The NE555 parts were commercial temperature range, 0 °C to +70 °C, and the SE555

part number designated the military temperature range, −55 °C to +125 °C. These were

available in both high-reliability metal can (T package) and inexpensive epoxy plastic

(V package) packages. Thus the full part numbers were NE555V, NE555T, SE555V,

and SE555T. It has been hypothesized that the 555 got its name from the three 5 KΩ

resistors used within, but Hans Camenzind has stated that the number was arbitrary.

Low-power versions of the 555 are also available, such as the 7555 and CMOS

TLC555.The 7555 is designed to cause less supply noise than the classic 555 and the

manufacturer claims that it usually does not require a "control" capacitor and in many

cases does not require a decoupling capacitor on the power supply. Those parts should

generally be included, however, because noise produced by the timer or variation in

power supply voltage might interfere with other parts of a circuit or influence its

threshold voltages.

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Details of Pins of 555 Timer

The connection of the pins for a DIP package is as follows:

Fig.13 555 Timer Pin Connections

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Pin 5 is also sometimes called the CONTROL VOLTAGE pin. By applying a voltage to

the CONTROL VOLTAGE input one can alter the timing characteristics of the device.

In most applications, the CONTROL VOLTAGE input is not used. It is usual to connect

a 10 nF capacitor between pin 5 and 0 V to prevent interference. The CONTROL

VOLTAGE input can be used to build an a-stable multi vibrator with a frequency

modulated output.

Modes of Operation of 555 Timer

The IC 555 has three operating modes:

Non-stable Mode: In this mode, the 555 functions as a "one-shot" pulse generator.

Applications include timers, missing pulse detection, bounce free switches, touch

switches, frequency divider, capacitance measurement, pulse-width modulation (PWM)

and so on.

A-stable (free-running) Mode: The 555 can operate as an oscillator. Uses include LED

and lamp flashers, pulse generation, logic clocks, tone generation, security alarms, pulse

position modulation and so on. The 555 can be used as a simple ADC, converting an

analog value to a pulse length. E.g. selecting thermistor as timing resistor allows the use

of the 555 as a temperature sensor: the period of the output pulse is determined by the

temperature. The use of a microprocessor based circuit can then convert the pulse

period to temperature, linearize it and even provide calibration means.

Bi-Stable Mode or Schmitt Trigger: The 555 can operate as a flip-flop, if the DIS pin is

not connected and no capacitor is used. Uses include bounce-free latched switches.

555timer in A-stable mode is used.

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A-Stable Mode of Operation of 555 Timer:-

Fig.14 Standard 555 A-stable Circuit

In A-stable mode, the 555 timer puts out a continuous stream of rectangular pulses

having a specified frequency. Resistor R1is connected between VCC and the discharge

pin (pin 7) and another resistor (R2) is connected between the discharge pin (pin 7), and

the trigger (pin 2) and threshold (pin 6) pins that share a common node. Hence the

capacitor is charged through R1 and R2, and discharged only through R2, since pin 7 has

low impedance to ground during output low intervals of the cycle, therefore discharging

the capacitor.

In the a-stable mode, the frequency of the pulse stream depends on the values of R1, R2 and

C:

The high time from each pulse is given by:

and the low time from each pulse is given by:

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where R1 and R2 are the values of the resistors in ohms and C is the value of the

capacitor in farads.

The power capability of R1 must be greater than.

Particularly with bipolar 555s, low values of must be avoided so that the output stays

saturated near zero volts during discharge, as assumed by the above equation. Otherwise

the output low time will be greater than calculated above. The first cycle will take

appreciably longer than the calculated time, as the capacitor must charge from 0V to 2/3

of VCC from power-up, but only from 1/3 of VCC to 2/3 of VCC on subsequent cycles.

To achieve a duty cycle of less than 50% a small diode (that is fast enough for the

application) can be placed in parallel with R2, with the cathode on the capacitor side.

This bypasses R2 during the high part of the cycle so that the high interval depends

approximately only on R1 and C. The presence of the diode is a voltage drop that slows

charging on the capacitor so that the high time is longer than the expected and often-

cited ln(2)*R1C = 0.693 R1C. The low time will be the same as without the diode as

shown above. With a diode, the high time is

Where Vdiode is when the diode has a current of 1/2 of Vcc/R1 which can be determined

from its datasheet or by testing. As an extreme example, when Vcc= 5 and Vdiode= 0.7,

high time = 1.00 R1C which is 45% longer than the "expected" 0.693 R1C. At the other

extreme, when Vcc= 15 and Vdiode= 0.3, the high time = 0.725 R1C which is closer to the

expected 0.693 R1C. The equation reduces to the expected 0.693 R1C if Vdiode= 0.

The operation of RESET in this mode is not well defined, some manufacturers' parts

will hold the output state to what it was when RESET is taken low, others will send the

output either high or low.

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Types/Varieties of Stun Gun

1. Compact Stun Guns

The compact handheld stun guns are about the size of a TV remote or calculator and

they must touch the subject when used. The original XR-5000 design in 1983 had the

electrodes spread farther apart to make the noisy electric arc between the electrodes as a

more visible warning. Some such devices are available disguised as other objects, such

as umbrellas, mobile phones or pens.

Fig.15 A concealable weapon shaped and sized like a lipstick tube

2. Electric Shock Prods

The larger baton-style prods are similar in basic design to an electric cattle prod. It has a

metal end split into two parts electrically insulated from each other, or two thin

projecting metal electrodes about 2.5 centimeters (1 in) apart, at an end of a shaft

containing the batteries and mechanism. At the other end of the shaft are a handle and a

switch. Both electrodes must touch the subject. In some types the sides of the baton can

be electrified to stop the subject from grasping the baton above the electrodes.

Some models are built into long flashlights also designed to administer an electric shock

with its lit end's metal surround (which is split into halves insulated from each other).

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Fig.16 Electric Cattle Prod from the 1950s

3. Stun Belts

A stun belt is a belt that is fastened around the subject's waist, leg, or arm that carries a

battery and control pack, and contains features to stop the subject from unfastening or

removing it. A remote-control signal is sent to tell the control pack to give the subject

an electric shock. Some models are activated by the subject's movement.

The United States uses these devices to control prisoners. One type is the REACT belt.

Some stun belts can restrain the subject's hands and have a strap going under his groin

to stop him from rotating the belt around his waist to reach its battery and control pack

and trying to deactivate it. Stun belts are not generally available to the public

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Stun Gun Design and Operation

Stun Gun Design

Actually, here we require two of designing- the a-stable multi-vibrators design and voltage

multiplier design.

Fig.17 Circuit Diagram of Stun gun

Designing the circuit requires pioneer step of deciding the output voltage. Here our

requirement is to generate a 10KV DC voltage from 1000V.

From the equation,

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

To obtain voltage of 100KV, 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 at least

2000V. Since here operating frequency is low, of the order of Hertz, we require a 2500V,

10uf.

For designing the a-stable multi-vibrator circuit, we select a 555 timer. To design a 555

timer in a-stable mode, passive external components need to be selected.

Assuming a maximum operating frequency of 50Hz and a duty cycle of 75%, I

calculate R1 to be around 1.44K, R2 around 720 ohms and C1 around 10uf. Here we

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select a 2K potentiometer, 720 ohm resistor and 10uf capacitor. Since this is a low

frequency operation, a MOSFET IRF530 is used.

Operation of Voltage Multipler in Stun Gun Circuit

As soon as the switch S1 is pressed, the a-stable 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 D4 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 cycle, a voltage equal to 4 times the input

peak voltage is obtained at point 2.

4. The sane procedure applies for other two stages and finally a voltage equal to 10

times the input voltage is obtained at point 5.

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Testing and Caution during Operation

Testing

Before inserting the battery and closing the case, a few test measurements should be made to

ensure correct operation.

With the ground clip connected to the battery (do NOT connect the complete clip to the

battery ONLY the ground), connect a volt or multi-meter between the positive clip and

the positive terminal of the battery. Set the meter for current reading, and press S1. You

should measure a current of approximately 300 to 500mA. The 'Neon' light should be

glowing. With a high voltage multi-meter or VOM, you should measure about 2000

volts on the output terminals. Those measurements indicate proper circuit operation. Let

the unit run for about one minute (keep pressing S1). Transistors Q1 and Q2 should be

warm, but not hot to the touch (BE CAREFUL!). Insert the battery in the holder and

close the case. That wraps up the

Operation and Use

Activate the unit by pressing S1. The Neon-bulb will light indicating the stun gun is

fully charged and ready to use. Notice also that only one pole of the neon light will

glow, indicating DC voltage present. It is important to remember that the device holds a

charge even after S1 is off. To discharge, (do not press S1) touch the electrodes to a

metal object and note the healthy spark discharge.

The Electronic Stun Gun was designed as a self-defense weapon for use against vicious

dogs or other attacking animals. The device is most effective when the electrodes contact

an area of low resistance such as skin or flesh. Those include the snout or mouth since the

resistance of those areas is much lower than areas of hair or of fur. The electrodes could

be pointed to penetrate these areas better. The stun gun generates great stopping power.

One contact will give a powerful jolt and should discourage any further attacks.

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The device can burn and heat materials with low resistance. Those include flesh,

moistened paper or wood, etc. That makes the unit potentially hazardous to humans.

Remember, that the stun gun is not a toy but a quality electrical appliance and therefore

must be treated accordingly. Use the mostly discretion with this device! Another use for

this device is as a high voltage DC power supply. It may be constructed as variable

power supply if output taps are taken from various stages of the voltage multiplier

section. Remember, always disconnect the battery and fully discharge the capacitors

before working with the circuitry. Note that if you decide to 'Turbo-charge' your unit,

select diodes which can handle that voltage. This unit can easily be damaged (and stops

working) by incorrect parts choice. So be careful and watch yourself.

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Advantages

1. Stun guns come in many shapes in forms, making them easier to use quickly and

effectively.

2. A stun gun can be particularly effective when a victim has already been grasped by

the attacker and the stun gun is available for use.

3. Stun guns also require less accuracy than other devices and are often enough of a

threat to deter an attacker from actually attacking in many cases.

Disadvantages

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.

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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.

4. It can be used as a self defence equipment, especially for ladies.

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References

1. http://www.electronicshub.org/stun-gun-circuit/

2. http://www.555-timer-circuits.com/stun-gun.html

3. http://www.electroschematics.com/335/stun-gun-simple-schematic/

4. http://www.homemade-circuits.com/2013/08/stun-gun-circuit.html

5. http://www.instructables.com/id/DIY-Taser/