An Introduction to TASER® Electronic Control Devices, History ...

An Introduction to TASER® Electronic Control Devices,

History, Electricity, Electrical Stimulation, Electrical Measurements, and the Human Body

Rev: E November 10, 2008 Page i

TABLE OF CONTENTS

INTRODUCTION .................................................................................................. 1 Early Medical Considerations of Electricity ........................................................ 1

WHAT IS ELECTRICITY? ..................................................................................... 3 Hoover Dam Water Analogy .............................................................................. 4 Water Hose Analogy ......................................................................................... 4 Joule (J) – Water Analogy ................................................................................. 5

BASIC ELECTRICAL PRINCIPLES (HIGH SCHOOL PHYSICS 101) .................. 6 Power Supply Limitation .................................................................................... 6 50 kilovolt (kV) from A Battery of Small Cells? .................................................. 6

WHY TASER DEVICES ARE HIGH VOLTAGE .................................................... 7 50,000 V DO NOT ENTER THE BODY ................................................................ 7 IT’S NOT THE VOLTS, IT’S THE DELIVERD CHARGE THAT MATTER THE MOST ................................................................................................................... 8 TASER CURRENT (AMPERES) DOES NOT LAST LONG ENOUGH TO FORESEEABLY AFFECT THE HUMAN HEART ............................................... 10

Limited by the Very Limited Battery Power Supply .......................................... 11 Power Limited by Wire Conductors ................................................................. 11 Power Limited by Delivery ............................................................................... 11 In Summary ..................................................................................................... 13 Average Current vs. Root Mean Square (RMS): ............................................. 13 Average Current .............................................................................................. 13 For TASER ECDs RMS Calculations Do Not Provide an Accurate Picture ..... 13 Average Current Relevant to TASER Devices ................................................ 14 2002: TASER Tried Using RMS Calculations (Learning from Experience) ..... 14

BASIC TASER DEVICE OPERATING PRINCIPLES .......................................... 15 Telephone Network Communication Analogy ................................................. 17 Effects of Repeated Pulses on Muscle Tension .............................................. 18

HISTORY OF TASER DEVICE TECHNOLOGIES ............................................. 19 1967 – NASA Scientist Jack Cover’s TASER TF-76 ....................................... 19 Tasertron Emerged ......................................................................................... 19 1980s: Studies and Risk Utility Comparisons .................................................. 19 Early 1990s: The Need for Non-Firearm Self-Defense .................................... 19 ICER Corporation Formed ............................................................................... 20 TASER 34000 – 2nd Generation TASER Device ............................................. 20 1994: TASER 34000 Limited to Non-Law Enforcement .................................. 20 Nov. 1995: The Czech Experience: Original TASER Devices Did Not Get the Job Done! ........................................................................................................ 21 1996: ADVANCED TASER M26 Is Born ......................................................... 21 Stratbucker Testing ......................................................................................... 21 TASER M26 Developed .................................................................................. 22 TASER M26 Emerges – 3rd Generation TASER Device ................................. 22 Medical and Scientific Research ..................................................................... 22 Late 1999: ADVANCED TASER M26 .............................................................. 23 May 2003 – TASER X26 Debuted – 4th Generation TASER Device ............... 23

Rev: E November 10, 2008 Page ii

2007 – TASER eXtended Range Electronic Projectile (XREP™) – 5th Generation TASER Device .............................................................................. 23 TASER C2™ ECD ........................................................................................... 23

BASIC TASER DEVICE OPERATIONS ............................................................. 24 Transformers: Analogy: An Electrical Lever .................................................... 24

THE TASER DEVICE CIRCUIT: AN ILLUSTRATIVE LOOK .............................. 25 Basics of Nerve and Muscle Stimulation ......................................................... 26 The Neuromuscular Junction .......................................................................... 27 Tetanus ........................................................................................................... 27 How the TASER Device Does What It Does to the Body ................................ 28 TASER Device Outputs and Comparisons ...................................................... 29 TASER Risk Benefits ...................................................................................... 33

DEGREE OF CERTAINTY ................................................................................. 33

Rev: E November 10, 2008 Page iii

TABLE OF FIGURES

Figure 1 Electrotherapy 1785. From Adams (1785). ............................................. 1 Figure 2 Galvani (1790) From Beard & Rockwell 1878. ........................................ 2 Figure 3 Let-go testing. From Dalziel, 1972. ......................................................... 2 Figure 4 Electricity is the Flow of Electrons through a Conductor ......................... 5 Figure 5 Mother and Daughter Experience up to 20 Million V from a Van de Graff Generator .............................................................................................................. 8 Figure 6 Common U.S. Wall Outlet and TASER ECD Waterfall Analogy Comparison .......................................................................................................... 9 Figure 7 Current Comparison ............................................................................. 10 Figure 8 Maximum Power Battery of (8 AA) Alkaline Cells ................................. 12 Figure 9 M26 Battery: Alkaline vs. NiMH Cells 10/16/06 ..................................... 13 Figure 10 Neurons. Fig. 3.1 of Reilly, 1998. ........................................................ 15 Figure 11 Sensory Receptors. Fig. 3.16 of Reilly (1998). ................................... 16 Figure 12 TASER Devices Stimulate the Motor and Peripheral Nervous Systems with Pulses Similar to Those Used by Nerves to Communicate ......................... 17 Figure 13 Fig. 3.22 from Reilly, 1998. ................................................................. 18 Figure 14 Understanding Transformers Analogy ................................................ 24 Figure 15 An Illustrative Representation of the TASER M26 Circuit ................... 25 Figure 16 Air Force Research Lab Tests Show TASER M26 Muscle Contractions at 40% or less of Maximum Contraction Force ................................................... 29 Figure 17 Comparison of Current Output of AIR TASER 34000 and TASER M26 ............................................................................................................................ 30 Figure 18 Comparison of Current Output of ADVANCED TASER M26 and TASER X26 ........................................................................................................ 32 Figure 19 Examples of TASER Risk Benefits ..................................................... 33 TABLE OF TABLES

Table 1 Electricity/Water Analogy ......................................................................... 5

Rev: F November 10, 2008 Page 1

INTRODUCTION

The purpose of this appendix is to provide a basic partial overview of the fundamental operating principles and concepts of how TASER1®-brand Electronic Control Devices (ECDs, or devices) work. To many people, electricity sounds dangerous. Indeed, it can be. However, many people do not realize that life cannot exist without electricity. We are not talking about life being difficult without television, cell phones, and electric light bulbs. Literally, the life process cannot happen without electricity. Without electricity, Earth would be nothing but a barren rock in the cosmos.

While much of what follows could come right out of high school physics 101 and biology 101, many of these concepts may be outside the existing knowledge and understanding of most people who do not study and/or keep abreast of these areas. Additionally, due to early life experiences many people are electricaphobic in that they have an unreasonable fear (or phobia) of electricity.

It is important to keep in mind that all electricity is not the same. Just as all “balls” are not the same – a nerf ball, whiffle ball, beach ball, ping-pong ball, golf ball, racquet ball, tennis ball, dodge ball, softball, baseball, basketball, soccer ball, football, medicine ball, bowling ball, and wrecking ball are different – the same is true for electrical discharge or delivered electrical charge or energy. A lightning bolt or a high-current power line would be equivalent to a wrecking ball, a bowling ball to a 110 V AC outlet, and a handheld, battery-powered ECD would be approximately equivalent to a tennis ball.

Early Medical Considerations of Electricity

Figure 1 Electrotherapy 1785. From Adams (1785).

1 AIR TASER, M26, and X26 are trademarks of TASER International, Inc. TASER® and ADVANCED TASER® are registered trademarks of TASER International, Inc.


Figure 2 Galvani (1790) From Beard & Rockwell 1878.

Figure 3 Let-go testing. From Dalziel, 1972.


WHAT IS ELECTRICITY?

Electricity is the flow of electrons through a conductor (a physical material that allows an electric current to flow through it). Electrons are the negatively charged subatomic particles that orbit around the positively charged nucleus of every atom.

Since a flow of electrons through a conductor, such as a metal wire, cannot physically be seen, it is helpful to think of the analogy of water flowing through a pipe, a fire hose, a garden hose, or a drinking straw. This analogy may help to visualize and understand some of the basic principles of electricity that many students learn about in high school science classes.

Basically, there are five (5) key elements to characterize electricity: Voltage, Current, Power, Energy, and Charge.

VOLTAGE2 (measured in “volts” and symbolized by “V”): Also called electromotive force, voltage is the pressure behind the flow of electrons. As will be more fully explained later, it is important to note that high voltage in and of itself is not necessarily dangerous. A strong static electricity shock can be in excess of 30,000 volts (V) and a Van de Graff generator that many children have experienced in science classes or museums can generate up to 25,000,000 V.

In the water analogy, voltage would be the pressure measured in pounds per square inch. Voltage can also be analogized to height – from how high does the water fall? The higher a waterfall or rain from the sky, the greater the pressure with which the water hits the ground. Voltage is measured in volts (one volt is the amount of force required to send one ampere (A) of current through a resistance of one ohm [Ω]).

CURRENT (measured in “amperes” and symbolized by “A” or “I”): Current, measured in amperes (A), measures the flow rate, how many electrons flow each second. The ampere (A) is the International System of Units (SI) base unit of electric current or amount of electric charge per second.

CHARGE (measured in “coulombs” and symbolized by “C”): Is the total number of electrons moved over a given period of time. A coulomb (C) is the SI base unit of electric charge. One coulomb is equal to 6.24150962915265 × 1018, or approximately 6.24 quintillion, electrons or elementary charges. One C is the amount of electric charge transported by a current of 1 A in 1 second (s).

2 Voltage, expressed in volts (V), (often also referred to as electric or electrical tension) is the difference of electrical potential between two points of an electrical or electronic circuit. Voltage measures the potential energy of an electric field to cause an electric current in an electrical conductor. Depending on the difference of electrical potential the voltage may be called extra low voltage, low voltage, high voltage, or extra high voltage.


The water analogy would be the water flow rate measured in gallons per second. Current is measured in amperes (A). One ampere (A) is equal to a flow rate of 1 C (approximately 6,240,000,000,000,000,000 electrons) per second. While this is a very large number, it is approximately equivalent to the number of water molecules in two (2) drops of water. In the water analogy, charge, measured in C, would be the total amount of water that has flowed, measured in gallons.

POWER (measured in “watts” and symbolized by “W” or “P”): The watt (W) is the SI derived unit of power, equal to one joule (J) of energy per second. One W is a small amount of power. A person climbing a flight of stairs is doing work at a rate of approximately 200 W. Power is thus the measure of the amount of energy generated by an electric current in one second. Power is a function of the voltage and the current [P = V x A].

Hoover Dam Water Analogy

Consider the water analogy that the Hoover Dam generates power from a flow of water. The amount of power is determined by how much water pushes through the generator, and how much pressure is behind the water. In fact, in electrical terms there is a very simple relationship between power, current, and voltage. Power is measured in watts.

Water Hose Analogy

In the water analogy, power is the rate at which energy is applied. Think of a fire or garden hose, or a drinking straw, with a certain amount of water being ejected at a certain amount of pressure. The power you would feel is a function of both the amount of water and the pressure behind it.

A good analogy is a waterwheel mill. If the current is low (trickling flow) but the voltage (pressure) is high because the water is falling 100 feet, there will not be much power. Conversely, if the flow is rapid (high current) but the stream is level (no potential or voltage or pressure) then the power will also be low. Only when there is a heavy current and a high potential (large fall in water height) is high power produced. So, in a water wheel, power = current times pressure (or height). In an electrical device, power (W) = current (A) times voltage (V). One horsepower is equal to 746 watts. So, a high performance, 300-horsepower (hp) car engine produces 223,800 watts.

ENERGY (symbolized by “E”): Energy is the total energy from a given amount of power applied for a given period of time. The relationship between Energy (E) and Power (P or watt [W]) is like the relationship between Current (A) and Charge (C). Current is the flow rate of Charge (C). Power (W) is the Flow Rate of Energy. Energy is measured in joules (J). The J is the SI unit of electrical, mechanical, and thermal energy. A J is the unit of electrical energy equal to the work done when a current of one ampere (A) is passed through a resistance of


one ohm (Ω) for one second (s). Hence, 1 watt (W) of Power = 1 (J) joule of Energy per second (s).

One J is a very small amount of energy. One J is approximately the amount of energy:

• required to lift a small apple 1 meter (m) straight up;

• released when that same apple falls 1 m to the ground;

• the amount of energy, as heat, a quiet person produces every 1/100th of a second;

• the energy required to heat one gram (g) of dry, cool air by 1.39 degrees Celsius; or

• 1/100th of the energy a person can get by drinking a single drop of Pepsi® soft drink.

Joule (J) – Water Analogy

In the water analogy, think of a joule as a packet of energy. It could be the total energy from being hit with a garden water hose for twenty minutes, adding up all the power over that time (this would equate to a constant current delivered over a period of time). Or, it could be like getting hit with a single discrete pulse, such as a small water balloon (this would correspond to brief pulses of electric charge – similar to what a TASER device delivers). One joule is also 0.2388 calorie3 (as a measurement of heat, or thermal energy, created).

Figure 4 Electricity is the Flow of Electrons through a Conductor

Table 1 Electricity/Water Analogy

UNIT “WATER ANALOGY” “WATER UNIT” Voltage (in volts [V]) Volt (V) Pressure lbs / in2 or PSI Current (SI base unit – A) Ampere (A) Water Flow Rate Gal / Second Charge (SI base unit – C) Coulomb (C) Total Water Volume Gallons

3 A “calorie” is a very small amount of thermal energy. Often confused with kilocalorie (1,000 calories), the kilocalorie (kcal), often simply referred to as “calorie,” is the common measure for the amount of food energy. As an example, one drop of Pepsi soft drink has 21.14 calories or 0.02114 kcal.


UNIT “WATER ANALOGY” “WATER UNIT” Power (V) Voltage (V) x Current (A)

Watt (W) Flow Rate x Pressure

Energy (J) Power (W) x Time (s)

Joule (J) Water Balloon Flow Rate x Pressure x Time

Resistance Ohms (Ω) Diameter of Water Hose Centimeters (cm) ECD Current Pulses PPS Bursts of Water Water Balloon BASIC ELECTRICAL PRINCIPLES (HIGH SCHOOL PHYSICS 101)

A very important aspect to understand about electricity as used by an ECD is that in order for the ECD to be effective, the electricity must flow in a complete circuit. In an ECD, an electric current starts at a battery power source, flows through a circuit, and must return to the power source. In this respect, electricity seems different than the flow of water – which simply flows downhill due to gravity or through a pipe, hose, or straw due to pressure. But eventually it ends up in the ocean and is recycled through evaporation and rain back into the water supply. In ECD electricity, the flow must return to the source. In some cases, such as the TASER device, the source is the energy cells, or multiple cells in a battery (of cells). In other circuits, such as your home, the source of electricity is the local power station that generates the power.

Power Supply Limitation

In any given electric circuit, the total power is limited by the power supply. In the case of the TASER device, the power supply is the very limited power battery of cells. Hence, the power delivered by the TASER device cannot exceed the power supplied by the battery of eight AA penlight cells (AA cells are used in the TASER M26 – the power level is even smaller in the TASER X26™ (X26), with its two three-volt digital camera-type cells).

50 kilovolt (kV) from A Battery of Small Cells?

A common question often asked is, “How can the TASER device generate up to 50,000 peak arcing volts output from the very limited power of eight AA cells or two 3 V cells?” The answer is, the TASER device uses transformers and the principles of physics that define the relationship between power, current, and voltage to generate the high voltage output from the very minimal power supply input. As will be explained later, the 50,000 V do not enter (are not delivered into) a person’s body.

• From an ADVANCED TASER® M26™ (M26) device only 5,000 V peak, 3400 V average over the duration of the pulse, enter the body, or 1.44 V average (one-second baseline)4.

4 All numbers are calculated based upon a 400 Ω resistance.


• From the TASER X26 only 1,200 V peak, 400 V average over the duration of the pulse, enter the body, or 0.84 V average (one-second baseline).

To say that 50,000 V is delivered to a person from a handheld battery-powered TASER ECD is sensationalistic and very misleading.

WHY TASER DEVICES ARE HIGH VOLTAGE

Short Answer: TASER ECDs are high voltage to avoid the necessity of having to embed TASER probes into a person’s body to deliver the electrical energy. To be able to jump up to approximately 50 millimeters (mm), or 2 inches, combined air gap. This allows for minimizing the discharge velocity of the probes from the TASER cartridge.

A TASER device needs to generate the high voltage to jump the air gap to avoid the necessity of embedded probes. Consider a garden hose; the higher the water pressure, the farther the water will eject from the end of the hose. The same holds true for a drinking straw. Similarly, the TASER device uses high pressure (high voltage) to eject electrons from the tips of the darts (probes) across a gap of up to approximately 2 inches of accumulated air and clothing and into a conductor such as the human body. Because of the high voltage generated, the darts (probes) from the TASER device do not have to penetrate, or even touch the skin, to deliver electrical energy. The high voltage allows the TASER device electrical output to jump through up to 2 inches cumulative of air or clothing to complete the circuit with the target’s body. Electricity flows easily through metal wires. However, it cannot flow through the air very easily. It takes about 1,000 V of “pressure” to cause an electric arc to jump across a roughly 1 millimeter (mm) air gap. Accordingly, the TASER device must generate a peak of up to 50,000 V to jump across a 50 mm (roughly 2-inch) air gap.

Without the high peak arcing voltage, the TASER device would need to have much longer probe-tip needles coupled with far stronger probe propulsion to ensure penetration through various types of clothing a subject may wear and to ensure skin penetration and continuous attachment to have any effect. This would make the TASER device far more intrusive and more likely to penetrate deeper into the body. In this respect, the usage of high voltage allows TASER to make the device a safer, less intrusive tool.

50,000 V DO NOT ENTER THE BODY

Even though the M26, ADVANCED TASER M18 and M18L, TASER X26, and TASER C2™ Personal Protector have a 50,000 peak open circuit voltage to jump the air gap, none of these TASER devices delivers 50,000 V to a person’s body. The M26 has an average (one-second baseline) voltage of 1.44 V, with a peak loaded voltage of 5,000 V, and a 3,400 V average over the duration of the pulse. The X26 has an average (one-second baseline) voltage of 0.84 V, with a peak loaded voltage of 1,200 V, and a 400 V average over the duration of the pulse.


IT’S NOT THE VOLTS, IT’S THE DELIVERD CHARGE THAT MATTER THE MOST

Many people ask how safe a TASER device can be since it generates a high (peak open circuit) voltage. In fact, voltage is not generally a key measure of electrical safety. While voltage indicates the pressure behind a flow of electrons and how far that electric current will arc through the air, voltage is generally not a key indicator of safety or effectiveness when it comes to stimulating the human body. The key indicator for safety and effectiveness is the number of electrons delivered into the body – i.e. the current (A) over time, or the total electric charge (C) in very short duration discrete pulses, and not the high open circuit peak voltage.

Figure 5 Mother and Daughter Experience up to 20 Million V from a Van de Graff Generator

To demonstrate this principle, note the above, a picture of a mother and daughter happily experiencing millions of volts from a Van de Graff Generator at a science museum. This Van de Graff generator creates very high voltage, but nearly zero current. Accordingly, while the static forces associated with the high voltage cause their hair to stand on end, they feel no sensation or ill effects because virtually no current flows.


Wall Outlet

Med Voltage: 110V

Continuous Current

High Current

Danger: High

TASER ECD

High Voltage: 5,000+ V

Pulsed Current

Low Current

Danger: Low

Figure 6 Common U.S. Wall Outlet and TASER ECD Waterfall Analogy Comparison

Another way to look at this is the difference between rainfall and a very large waterfall (such as Niagara Falls). Although rainfall travels thousands of feet it does not cause injury, while a very large waterfall travels a much lesser distance but has much more force, and thus can cause injury/damage. Another example is a fire hose versus a garden hose, or a common beverage drinking straw.


TASER CURRENT (AMPERES) DOES NOT LAST LONG ENOUGH TO FORESEEABLY AFFECT THE HUMAN HEART

Consider static electricity. Everyone has received at least one strong static electricity shock in their lifetime. The typical current pathway is from a doorknob through a fingertip and then through the chest and down through the legs to the floor. The shock can be painful and cause a significant muscle twitch, but it has never caused a cardiac arrhythmia, much less a death. A search of over a century of medical, scientific, and electrical literature shows only one case of a static shock possibly affecting the heart – and that individual claimed he was cured of atrial fibrillation (a fairly benign chronic arrhythmia) after a static shock.5

The current of a strong static shock would easily kill someone if it was continuous. But, it typically lasts less than a millionth [.0000001] of a second and is thus much too short to affect the heart.

Also, there is an international standard that sets out the electrical characteristics of a “strong static electricity” shock. This standard is necessary for many of the electrical devices we use today. Meaning, if a cell phone, a pager, a pace maker, etc. could not withstand a “strong static electricity” shock, then each of those electrical devices would soon be damaged. Thus, the International Electrotechnical Commission (IEC) has defined a “strong static electricity” shock as having electrical characteristics of 15,000 V and 30 A peak. (International Standard IEC-61000-4-2).

The maximum current output from a wall outlet is approximately 4,000 times higher current potential than that of a handheld, battery-powered TASER ECD.

Figure 7 Current Comparison

5 Screnock T. “Static Electricity Stops a Recalcitrant Arrhythmia.” Ann Intern Med. 130, no. 1 (January 5, 1999):78.


To appreciate TASER technology, one needs to only imagine a similar, very short shock (actually involving less peak current) but delivered repeatedly 15 to 25 times per second. This can immobilize a violent or resisting subject, but without significant risk of affecting the heart.

The TASER X26 is programmed to deliver a very short electrical pulse of approximately 100 microseconds (µs) duration with about 100 microcoulombs (µC) of charge at 19 pulses per second (PPS) for 5 seconds (s)6. The peak voltage delivered to the body is about 1,200 volts during the shock. The peak current of about 3 amperes is far less than that of a strong static electricity shock, which can be as high as 37.5 amperes.7 The average current from the TASER X26 is approximately 2 milliamperes (0.002 amperes).

Now, put together and consider as previously discussed: power, voltage, and current.

Limited by the Very Limited Battery Power Supply

First, the power in a circuit is limited to the power output of a power supply (in the case of a TASER device, this is the battery of cells). TASER makes a sophisticated device, but there is no perpetual motion machine; nor is the product nuclear powered.

Power Limited by Wire Conductors

This power is further limited by the wire conductors between the TASER device and the target. The TASER device wires are very small, and are not capable of delivering large currents that would require much larger wires such as automobile jumper cables or home electrical extension cords.

Power Limited by Delivery

Further, there is a mathematical relationship between power, voltage, and current:

P (power or watts [W]) = I (current or “A”) * V (voltage) The next section will discuss how transformers work to convert a given amount of power into different currents and voltages. But the big picture is simple – for a fixed amount of power, the HIGHER the voltage, the LOWER the current must be (not including power loss due to circuit inefficiencies, or failure of any circuit to perfectly move power without loss due to circuit inefficiencies).

6 This initial 5-second TASER X26/M26 discharge can be interrupted at any time simply by the X26/M26 operator activating the TASER device’s safety. 7 http://www.web-ee.com/primers/files/ESD_Tutorial.pdf


For example, if the battery of cells in a TASER device could output a maximum of 50 W (which it cannot), the table below would illustrate the maximum voltage and current it could generate:

Power Voltage Current 50 W = 5 V x 10 A 50 W = 50 V x 1 A 50 W = 500 V x 0.1 A 50 W = 50,000 V x 0.001 A These numbers are for illustration purposes, but the point is important: With a fixed power source and limitations such as limiting capacitors, the higher the voltage, the lower the output current must be! And, again, delivered current, or energy, is the key measurement for how electricity affects the body.

Actually, a TASER M26 with a battery of eight (8) AA [1.2 V or 1.5 V per cell] cells has a peak power in watts as seen in this graph:

Figure 8 Maximum Power Battery of (8 AA) Alkaline Cells


M26 Battery Alkaline Vs NiMH10/16/2006

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Duracell Ultra Alkaline Pulse Rate

Energizer NiMH 1700maHPulse Rate

Figure 9 M26 Battery: Alkaline vs. NiMH Cells 10/16/06

In Summary

• Voltage is the pressure that determines how far an electric arc can jump. • Delivered current or energy determines how intensely the human body will

react.

Average Current vs. Root Mean Square (RMS):

Average Current

Average current is the true flow of the amount of charge per second. Average current is calculated by adding the amount of charge in each pulse, add all of the pulses per second, and this total provides the electrical charge per second that is actually delivered.

For TASER ECDs RMS Calculations Do Not Provide an Accurate Picture

RMS current is calculated as an approximation for the current used when analyzing continuous alternating currents (AC), as opposed to pulsed current (e.g. the short duration pulses produced by TASER devices). Since an alternating current switches between positive and negative current flows if an average was calculated then the total would always average to zero – because the positive and negative elements cancel each other out. In order to measure currents in AC systems, engineers frequently use RMS for two reasons.


1. RMS eliminates the negative numbers. When a negative number is squared the number then becomes positive. When calculating RMS currents

a. first square all the values;

b. then average; and

c. then take the square root of the result.

2. RMS is very helpful to understand the amount of electrical power being consumed – power is a function of the square of the current (power = I2R). As an example, power can measure how much thermal energy or heat an electric current can generate, or how much light a light bulb can emit. Also, since electrical utility companies sell electricity based on power consumed (watt-hours [Wh]), RMS current is proportional to power and is hence a good measure for electricians and the utility company when dealing with continuous AC power.

Average Current Relevant to TASER Devices

The average current is more relevant to measuring TASER device outputs and far more relevant to neural stimulation, rather than heating (or continuous output), because it looks at the actual amount of electrical charge delivered. Because of the squaring effects used in RMS, the result is not an actual measure of the charge delivered. When using RMS with pulsed currents (where there are high peak currents for very short durations of time with relatively long pauses between pulses, the RMS calculations artificially significantly overstate the delivered current because the high peaks are squared before averaging).

2002: TASER Tried Using RMS Calculations (Learning from Experience)

Back in 2002, TASER had tried using RMS to attempt to measure TASER discharge. This was similar to trying to put a large square peg into a very small round hole. Because many of the U.S. and international electrical safety standards are based on alternating currents, and because those standards include mathematical adjustments for comparing pulsed currents, TASER fruitlessly attempted to measure the RMS current of the TASER device for comparison to those electrical safety standards that used RMS currents.


BASIC TASER DEVICE OPERATING PRINCIPLES

A TASER-brand device is an Electronic Control Device (ECD). Its intended purpose is to assist with capturing, controlling, and (when necessary) restraining a person with minimized risk (compared to most similar force tools) of serious injury. Prior less-lethal weapons function by merely causing pain or destructive injury. The intention with these other force tools and techniques are that the pain or the bodily injury will dissuade the subject from continuing an unwanted behavior and elicit cooperation. However, for a myriad of reasons people who are focused, under the influence of drugs, or who are pain insensitive may not feel pain, or may be sufficiently motivated to attack or fight through pain or even destructive injury (e.g., the Philadelphia barber shop incident). The proprietary Neuromuscular Incapacitation (NMI) technology in TASER devices does not solely rely on pain or on intended destructive injury for its incapacitating effect(s). Rather, the TASER device, in probe deployment mode, is designed to use short-duration, pulsed, low-energy electrical stimuli to interfere with the signals sent by the command and control systems of the body, at the peripheral and motor nervous system levels, to impair the subject’s ability to temporarily voluntarily control his own body.

Figure 10 Neurons. Fig. 3.1 of Reilly, 1998.

(a) Motor (muscle) and (b) sensory neurons are responsible for movement and sensation. They operate by propagating electrical signals.

The human nervous system is the command and control system of the human body. It has three primary elements:

• The central nervous system

• The motor nervous system

• The sensory nervous system

The central nervous system includes the brain and spinal cord. This is the command center, where all decision-making processes occur. The central nervous system can be thought of like the computer that controls the body, including all memory and conscious thought. Out from this central computer is a


network of “wiring” that carries signals to and from the brain. This “wiring” is composed of nerve cells, or “neurons” that function very similarly to the wiring of a computer network. In fact, neurons carry information in the form of electrical impulses to and from the brain.

The motor nervous system includes the nerves that carry commands from the brain out to the body. These nerves are primarily involved in muscular control. Commands from the brain are transmitted as patterns of electrical impulses through the motor nerves into the muscles, causing the muscles to move in certain patterns caused by the pattern of stimulation from the brain.

The sensory nervous system includes the nerves that carry information to the brain about the state of the body and its environment. Sensory nerves in the skin communicate heat, cold, touch, pressure, pain, and other sensations. Similarly, nerves carry visual data from the eyes, auditory data from the ears, and olfactory data from the nose. All of this data is transmitted in the form of electrical impulses along the neurons into the brain.

Figure 11 Sensory Receptors. Fig. 3.16 of Reilly (1998).

Section of the skin showing several types of sensory receptors. Sensory receptors can include sensors for touch, heat, feel, pressure, cold, etc.

Figure 12 is a conceptual representation illustrating the concept of operation of TASER devices. TASER devices use very short duration low energy electrical pulses that are somewhat similar to the pulses used by neurons to communicate. If you think of the nervous system as an electrical communications network, TASER devices are like remote controls that plug into that network, and temporarily take control of, or interfere with, the communication patterns between the brain and the body.


Figure 12 TASER Devices Stimulate the Motor and Peripheral Nervous Systems with Pulses Similar to Those Used by Nerves to Communicate8

Telephone Network Communication Analogy

One analogy helpful in understanding TASER technology is a telephone network. If person A is talking on the telephone with person B, and suddenly person C picks up another telephone handset and begins yelling into the phone, persons A and B can no longer effectively communicate – their conversation has been interfered with by person C’s intervening disturbance. However, when person C ceases yelling and disconnects, the normal conversation between A and B can resume again. The telephone hardware is not damaged by the yelling, it is just that the temporary over-stimulation of, or interference with the communication, the network prevented communication on a transient and temporary basis. Similarly, TASER devices cause stimulation of the nerves that is designed to be temporary in nature with minimal risk of causing serious damage to the hardware of the communication network by the interference.

8 This illustration is for illustrative conceptual purposes only. These are not intended to be scientific measurements of actual pulse characteristics, but to illustrate the basic concept for lay persons that the electrical discharge from the TASER device is a brief pulse which causes stimulation of neuron membrane mechanisms in a fashion similar to the capacitor-discharge type depolarization mechanism used by neurons in normal communications within the nervous system.


Effects of Repeated Pulses on Muscle Tension

Figure 13 Fig. 3.22 from Reilly, 1998.

Single muscle twitches will fuse together with sufficient repeated stimulus pulses producing increased muscle tension. TASER devices have a pulse rate of up to approximately twenty (20 ± 25%) pulses per second (pps).


HISTORY OF TASER DEVICE TECHNOLOGIES

1967 – NASA Scientist Jack Cover’s TASER TF-76

The original TASER device (the TF-76) was launched in the mid 1970s by National Aeronautics and Space Administration (NASA) scientist Jack Cover, the TASER device inventor. The TASER TF-76 fired two darts up to a distance of 15 feet. These darts remained attached to the handheld device by small, thin, insulated wires. The original TASER TF-76 used a gunpowder propellant to launch the darts. Because of the explosive (gun powder dart) propellant, the TF-76 was classified by the United States Treasury Department’s Bureau of Alcohol, Tobacco and Firearms, and also now Explosives, as a firearm. However, the TF-76 looked like a flashlight, not a firearm. Because it did not fit the specifications for either a pistol or a long gun, the TF-76 was classified as a Title 2 weapon – the same as a “sawed-off” shotgun. This classification meant that the TASER TF-76 could only be sold with special permits that were expensive and difficult to obtain (just as it would be for a “sawed-off” shotgun). Accordingly, the TF-76 could only effectively be sold to law enforcement agencies. While the Title 2 weapon classification did not adversely affect law enforcement agencies acquisition and use of the early TASER devices, it did prevent most civilians from acquiring, possessing, and using the devices. Shortly after the TF-76 was classified as a Title 2 weapon, TASER Systems (the company that made the TF-76) collapsed.

Tasertron Emerged

This early company eventually raised funding, re-emerging as a company called Tasertron, but struggled over the next decades and sold only a limited number of devices into the law enforcement marketplace. The Tasertron devices were originally offered in seven-watt versions and then later in eleven-watt models that had a 15-foot range and still used gunpowder propellant and were still classified as special class firearms.

1980s: Studies and Risk Utility Comparisons

In the 1980s there were numerous studies and risk utility analyses performed on ECDs. These included the Greg Meyer Los Angeles Police Department use of less-lethal force study and the Ordog mortality and morbidity study.

Early 1990s: The Need for Non-Firearm Self-Defense

In the early 1990s, two friends of Rick Smith’s (Corey and Todd) were shot and killed in a traffic altercation in Scottsdale, Arizona. This tragic event caused Rick Smith to start thinking about violent crime, and wondering why the state of the art in self-defense weapons required killlng, or at least reliably seriously injuring, other human beings – just as it had been for centuries. Mr. Smith came to believe that, if advances in technology could provide truly effective non-lethal


alternatives, many people would choose less-lethal weapons instead of lethal weapons – and many lives could be saved.

ICER Corporation Formed

In September of 1993, brothers Rick and Tom Smith formed ICER Corporation – a company whose mission would be to develop future less-lethal electronic weapons. As part of their early research, Rick contacted Jack Cover, the original TASER inventor. Jack Cover shared with Rick the history of the TASER technology, and he proposed a business model whereby they could develop a new, non-firearm version of the TASER device using a compressed air (or nitrogen), as opposed to gunpowder explosive, dart (probe) propulsion system. On October 15, 1993 they signed an agreement whereby Mr. Cover licensed his technology to ICER Corporation and joined the corporation as a full-time employee, infusing all of his knowledge and years of experience into the company, to help develop the next generation of TASER devices. Shortly thereafter, they then changed the name of the company to AIR TASER, Inc.

TASER 34000 – 2nd Generation TASER Device

In December of 1994, this work culminated with the launch of the AIR TASER model 34000. The design intention of the AIR TASER 34000 was to use the same electrical output as the original TASER TF-76, but with a compressed air propulsion system that would comply with federal firearm statutes and allow for private citizen sales.

The AIR TASER 34000 implemented an innovative new user accountability technology called Anti-Felon Identification (AFID), which used serialized confetti tags dispersed from every cartridge at the time of firing. These AFID tags would enable law enforcement to trace persons who misused a TASER device. This was another first for weapons’ use accountability – a self-defense device that left a tracer at the scene of the incident back to the purchaser. Also, the AFIDs are made in both paper and clear Mylar – making it more difficult for a criminal to pick up the AFID evidence of his crime. Also, some of the AFIDs are made to literally glow under a black light, thus making them very easy for law enforcement investigators to locate and recover.

1994: TASER 34000 Limited to Non-Law Enforcement

Shortly after the launch of the AIR TASER 34000 in 1994, AIR TASER Inc. was sued by Tasertron, the remainder of the original TASER systems company from the 1970s. Tasertron asserted that it had exclusive rights to the underlying technology for use in the law enforcement and military markets in North America. To avoid a costly legal battle, AIR TASER Inc. signed a non-compete agreement that recognized Tasertron’s exclusivity and precluded AIR TASER Inc. from selling to law enforcement or military agencies in North America until the patent in question expired in 1998.


Nov. 1995: The Czech Experience: Original TASER Devices Did Not Get the Job Done!

Around November of 1995, the company received an inquiry from the Czech police seeking a product demonstration in Prague. The AIR TASER’s non-compete agreement with Tasertron did not preclude foreign police or military sales. Accordingly, the company agreed to make, and was very eager to give, a presentation of the AIR TASER 34000.

Around December of 1995, Rick Smith flew to Prague with the company’s head of sales. After a brief technology demonstration, the Czech police asked for a volunteer demonstration. Prior to being hit with the AIR TASER 34000, the volunteer was strongly instructed – ordered – by his superior officer to fight through the (pain compliance) effects of the 34000 device and get to the shooter – Mr. Smith. In fact, several focused and highly motivated volunteers that day were all able to overcome the (pain compliance) effects of the AIR TASER 34000.

1996: ADVANCED TASER M26 Is Born

Following this highly embarrassing Czech debacle, the company set out to develop a more effective device – a device that would not only involve discomfort, but also interfere with voluntary muscle control. The result of this development was the TASER M26. Earlier generations of TASER devices such as the TF-76 and the AIR TASER 34000 caused a strong peripheral-nerve shock sensation. However, focused or pain-insensitive subjects, such as the police volunteers in Prague, could fight through these effects. Accordingly, these earlier-generation devices can be considered stun devices. Their effects may psychologically stun the subject, but they did not cause involuntary incapacitation.

Stratbucker Testing

In late 1995, TASER contacted Dr. Robert Stratbucker, M.D., Ph.D. (the leading medical and scientific expert on electrical weapons at the time), and retained him to conduct a complete relevant electrical, medical, and scientific literature review and to conduct safety studies of the impulse generator module of the TASER device. The goal of the study was to perform an analysis to establish a margin of safety for the AIR TASER 34000 by testing significant increases in relevant electrical characteristics and evaluating the physiological response.

Dr. Stratbucker was chosen to test the devices because he had over a decade of experience in researching and testing a number of similar devices both physically and physiologically in his laboratory and had become quite familiar with the necessary procedures to accurately accommodate such testing. Dr. Stratbucker had even demonstrated electronic weapons by using a stun gun on a U.S. Attorney General.


Dr. Stratbucker conducted the tests in January 1996. The studies included skeletal muscle response and assessment of any possible affect on cardiac rhythm. For the cardiac rhythm testing a three-channel, battery-powered cardiograph unit was continuously employed to accomplish orthogonal lead axes. As a realistic necessity, the tests also included physiologic and biomarker monitoring to assure physiologic stability.

Dr. Stratbucker’s experiments corroborated earlier findings in consulting reports and peer review journals9 that the electrical emission from stun-type pulse generators, delivered to the body surface in the recommended manner did not cause serious cardiac rhythm abnormalities in the otherwise healthy adult swine heart. As the study investigated outputs equivalent to 400% the capacitance and 300% the battery voltage of the standard AIR TASER 34000, an adequate margin of safety appeared to exist.

Due to Dr. Stratbucker’s qualifications and extensive knowledge and history with electronic devices he later became TASER’s Medical Director.

TASER M26 Developed

Mr. Smith was proud to have led the development team, designed the test methodology used to develop the TASER M26, and was the listed inventor on the patent for the electrical waveform of the M26.

TASER M26 Emerges – 3rd Generation TASER Device

Because the earlier stun devices did cause a strong overwhelming discomfort (pain) sensation, they clearly caused some degree of stimulation of the sensory nervous system. However, there was little or no interference with or impairment of volitional muscular control with these early devices. In contrast, the new TASER M26 was designed to cause significant, uncontrollable muscle contractions capable of incapacitating even the most focused and aggressive combatants. Accordingly, this new technology was termed Electro-Muscular Disruption (EMD). More recently, a new term was adopted that was more accurately descriptive terminology: Neuromuscular Incapacitation (NMI).

Medical and Scientific Research

During the development of the TASER M26 medical, scientific, and engineering literature was extensively researched with regard to electrical energy, charge,

9 O.Z. Roy and A.S. Podgorski, Tests on a Shocking Device - the Stun Gun. Med. & Biol. Eng. & Comput, 1989, 27, 445-448. Robert A. Stratbucker and Matthew G. Marsh. IEEE. The Relative Immunity of the Skin and Cardiovascular System to the Direct Effects of High Voltage - High Frequency Component Electrical Pulses. Proc. IEEE Engineering in Medicine & Biology Conference, October 1993, San Diego, CA. Pearce, J.A., et. al: Myocardial Stimulation with Ultrashort Duration Current Pulses. PACE, Vol. 5, January-February 1982.


safety of electrical devices, similar forms of electrical devices, etc. This research has been continuously ongoing since the mid-1990s.

Late 1999: ADVANCED TASER M26

The ADVANCED TASER M26 was launched in late 1999, with an initial shipment of thirty (30) M26 devices to the New York City Police Department, with significant shipments starting in early 2000. By this time, the company had changed its name to TASER International, Inc. to signify the company had more than just the one AIR TASER product. The TASER M26 was adopted by thousands of law enforcement agencies, and was hailed as a state-of-the-art breakthrough – as the first less-lethal weapon capable of stopping aggressive, focused, or drug-impaired persons. In addition to the AFID system, the TASER M26 implemented a new accountability control technology – the dataport. The dataport is a function wherein the M26 would record the time and date of every five (5) second discharge trigger pull10 in order to allow law enforcement agencies to monitor use of the device – another use-of-force accountability break through.

May 2003 – TASER X26 Debuted – 4th Generation TASER Device

In 2003, TASER introduced the TASER X26. The X26 implemented a newer, more efficient electrical stimulation pulse called “Shaped-Pulse Technology.” This “Shaped Pulse Technology” pulse allowed for a more efficient power supply that enabled the X26 to be packaged in a form factor that was approximately 60% smaller and 60% lighter than the M26. However, the X26 design was tuned in laboratory testing to deliver an incapacitating effect that caused muscular contractions approximately 5% stronger than those of the M26.

The TASER X26 has been very well received and as of early 2006 accounts for the majority of the company’s law enforcement ECD shipments.

2007 – TASER eXtended Range Electronic Projectile (XREP™) – 5th Generation TASER Device

The XREP projectile is self-contained, wireless, and fires from a 12-gauge shotgun. It delivers similar Neuro Muscular Incapacitation (NMI) bio-effect as the handheld TASER X26 ECD, but can be delivered to a distance of 65 feet (20 meters [m]), combining blunt impact with field-proven TASER NMI.

TASER C2™ ECD

The TASER C2 is designed for personal protection. Utilizing the same technology as law enforcement models, the TASER C2 is designed to have strong take down power. 10 Also, the M26 records a datapoint entry with each five (5) seconds of continuous device discharge.


BASIC TASER DEVICE OPERATIONS

It is common for people to ask, “How can the TASER device generate 50,000 V from 12 V or less at the battery of cells (for the TASER M26)?” The answer is that TASER devices use a series of transformers and capacitors, together with the principles of physics (P = I * V).

Transformers: Analogy: An Electrical Lever

There’s a well-known stunt performed by acrobats using a “see-saw” device as a lever. Two acrobats jump from a given height (say 10 feet) onto one side of the lever. On the other side, a single acrobat is launched twice as high into the air. The lever transfers the momentum of the two acrobats into one acrobat, sending him twice as high.

Figure 14 Understanding Transformers Analogy

One can think of a transformer as an electrical lever. As electrons enter one side of the transformer from a certain voltage (similar to the height of the acrobats’ jump), the leverage ratio of the transformer transfers this energy to electrons on the output side of the transformer. Depending on the design of the transformer, it can either step-up the output voltage, or step it down. In either case, the transformer is constrained by the power input (P = I * V).

In its simplest form, the transformer “trades” volts for amperes, or vice versa. In the example above, if 2 amperes of current at 10 volts are delivered into this transformer, 1 ampere of current at 20 volts will be the output. (Note that in the real world, transformers are not 100% efficient, so the actual output will be slightly less than the input.)


THE TASER DEVICE CIRCUIT: AN ILLUSTRATIVE LOOK

The battery of power cells is the power supply in any TASER device. In this illustrative example, the battery of cells function like a water faucet, supplying the power to the circuit. The “pressure” out of the battery of cells in the M26 is roughly 10 volts (it drops from 12 volts, or less, as the battery of cells is loaded) and the current is roughly 4 amperes; hence the total power from the batteries is roughly 40 watts.

Figure 15 An Illustrative Representation of the TASER M26 Circuit

The electric current from the battery of cells is directed into a transformer (Transformer 1) that steps up the voltage by a factor of roughly 200, from 10 to 2,000 volts. As the transformer steps-up the voltage by 200x, it also steps-down the current by 200x, from 4 amperes input to roughly 0.02 amperes (the actual output is less, about 0.013 amperes due to inefficiencies).

The output of Transformer 1 is connected to a capacitor. A capacitor is a device that stores electric energy, just like a bucket would store a flow of water. Similar to a bucket, a capacitor can only hold so much energy. Once the capacitor is full, it dumps its energy into Transformer 2. Transformer 2 steps the voltage up again, from 2,000 volts to a peak of 50,000 volts. Similarly, the current drops again to an even lower output current.


One important note – the 50,000 volts is a peak potential voltage, or open circuit voltage; it is not what is actually delivered to the person on the receiving end. Again considering the water analogy, the wires from the TASER device to the target are like hoses that carry the current. If a section of plastic wrap is placed over the end of a garden hose, the pressure will build up inside the hose. At some point, the plastic wrap will finally burst, and the water will flow out the end. When the plastic bursts and the water starts to flow out, the pressure inside the hose drops, and the pressure of the water flowing out is actually lower than the peak pressure that developed within the hose itself.

In a TASER ECD system, the wires do not always make contact with the skin of the target. If there is an air gap between the darts and the body of the subject, the air gap will function as a barrier, just like the plastic wrap on the hose. The voltage (pressure) will build up inside the TASER wires until it can break through the barrier (the maximum would be 50,000 volts, which can break through a barrier of approximately 2 inches of air gap). Once the barrier is breached, the voltage (pressure) drops immediately as the current flows through. In the case of the TASER M26, the maximum voltage delivered across the body of the target is about 5,000 volts, with only 1.44 volts average (one-second baseline). In the case of the TASER X26, the maximum voltage delivered across the body of the target is about 1,200 volts, with only 0.84 volts average (one-second baseline).

The big picture from this illustrative look at the TASER device is to understand that at each level, as the voltage is increased, the output current is decreased.

Basics of Nerve and Muscle Stimulation

As mentioned previously, the body’s neurons conduct electrical stimuli to and from the brain. When a neuron is in its resting state, electrically charged ions are pumped across the cell membrane such that net positive charge collects outside the membrane and a net negative charge collects inside the membrane. In this state, the membrane serves as a charged capacitor. When the nerve cell is stimulated, channels in the membrane open up temporarily, allowing the positive ions to temporarily rush across the membrane (opposites attract). At this moment in time, the voltage potential across the membrane briefly flips polarity as the charge balance reverses. This process is called an action potential. As an action potential occurs in one section of the cell membrane, the change in the electric fields causes the adjacent section of the membrane to depolarize. The result is a chain reaction of action potentials cascading down the length of the neuron, thereby carrying an electric impulse along the neuron.

One important point to understand about action potentials is that they come in only one magnitude. For each neuron, there is a threshold stimulation level. Once this threshold is attained, an action potential will occur. There are not different intensities of action potential, they are an “All-or-None” phenomenon. In other words, there is no such thing as a partial or weak action potential. Either the threshold potential is reached and an action potential occurs, or it is not


reached and no action potential occurs. (As an example, either a light switch is turned on or it is turned off … it is not [in this case] a “dimmer” switch.)

Each neuron can only deliver one magnitude of impulse. Whether a muscle contraction will be strong or weak is not a function of the magnitude of the impulses of the connected neurons (again, there is no difference between impulses). The difference is the pattern of impulses delivered.

The section below describes the process by which these nerve impulses cause muscular contractions:

The Neuromuscular Junction

Nerve impulses (action potentials) traveling down the motor neurons of the sensory-somatic branch of the nervous system cause the skeletal muscle fibers at which they terminate to contract. The junction between the terminal of a motor neuron and a muscle fiber is called the neuromuscular junction. It is simply one kind of synapse. (The neuromuscular junction is also called the myoneural junction.)

The terminals of motor axons contain thousands of vesicles filled with acetylcholine (ACh). When an action potential reaches the axon terminal, hundreds of these vesicles discharge their ACh onto a specialized area of postsynaptic membrane on the fiber. This area contains a cluster of transmembrane channels that are opened by ACh and let sodium ions (Na+) diffuse in.

The interior of a resting muscle fiber has a resting potential of about −95 millivolts (mV). The influx of sodium ions reduces the charge, creating an end plate potential. If the end plate potential reaches the threshold voltage (approximately −50 mV), sodium ions flow in with a rush and an action potential is created in the fiber. The action potential sweeps down the length of the fiber just as it does in an axon.

No visible change occurs in the muscle fiber during (and immediately following) the action potential. This period, called the latent period, lasts from 3–10 milliseconds (ms). Before the latent period is over, the enzyme acetylcholinesterase breaks down the ACh in the neuromuscular junction (at a speed of about 25,000 molecules per second) the sodium channels close, and the field is cleared for the arrival of another nerve impulse. The resting potential of the fiber is restored by an outflow of potassium ions. The brief (1–2 ms) period needed to restore the resting potential is called the refractory period.

Tetanus

The process of muscles contracting takes some 50 ms; relaxation of the fiber takes another 50 to 100 ms. Because the refractory period is so much shorter than the time needed for contraction and relaxation, the fiber can be maintained


in the contracted state so long as it is stimulated frequently enough (e.g., 50 stimuli per second).

Such sustained contraction is called tetanus. When shocks are given at one per second, the muscle responds with a single twitch. At five per second and 10 per second, the individual twitches begin to fuse together, a phenomenon called clonus. At about 50 shocks per second, the muscle goes into the smooth, sustained contraction of tetanus.

Clonus and tetanus are possible because the refractory period is much briefer than the time needed to complete a cycle of contraction and relaxation. Note that the amount of contraction is greater in clonus and tetanus than in a single twitch. As we normally use our muscles, the individual fibers go into tetanus for brief periods rather than simply undergoing single twitches.

How the TASER Device Does What It Does to the Body

TASER devices deliver very short duration electrical pulses at a rate of approximately 15–25 pulses per second. As mentioned earlier, the first generation stun devices such as the TASER TF-76 and the AIR TASER 34000 only delivered sufficient charge in each pulse to stimulate the sensory nerves close to the skin. Very little motor nerve stimulation occurred, resulting in relatively low effectiveness against focused, motivated, or pain-resistant subjects.

The TASER M26 and X26 deliver a similar train of electrical pulses, also at approximately 15–25 pulses per second. However, the M26 and X26 devices deliver more electrical charge in each pulse. This higher charge results in deeper nerves, such as motor nerves, being stimulated. As a result, the motor nerves between the two electrodes fire at a rate of roughly 20 pulses per second.

This stimulation rate is sufficient to cause clonus, where the individual twitches fuse together into a sustained contraction. However, it is well below the 50–60 pulses per second required to cause complete tetanus (a smooth, continuous contraction of the muscle tissue). Accordingly, the stimulation from the TASER device does cause less muscle contraction than the types of contractions caused voluntarily by the brain.

As noted before, both nerve cells and muscle cells can be stimulated with electricity (both nerve and muscle cells use action potentials during stimulation). The mechanism of stimulation from the TASER devices is not direct electrical stimulation of muscle tissue, but stimulation of motor nerves which then stimulate muscles in a nerve-mediated mechanism. This has been demonstrated in laboratory testing wherein a test animal was administered a drug which blocked the neuronmuscular junction (similar to curare). Before the drug administration, the application of the TASER device caused significant muscular contractions. After the drug administration, the TASER device application caused insignificant muscle reaction, demonstrating that the mechanism of effect is mediated by the


motor nerves not a direct electrical stimulation of the muscle tissue. This is an important concept in that the muscle contractions are mediated by the neuromuscular junction, just as in normal activity.

Figure 16 Air Force Research Lab Tests Show TASER M26 Muscle Contractions at 40% or less of Maximum Contraction Force

In fact, a study by Dr. James Jauchem at the Air Force Research Laboratory (AFRL) found that the intensity of the muscle contractions caused by the TASER M26 could be increased to more than 250% of the level of contraction from the field production M26. Accordingly, the M26 generates a muscle contraction approximately 40% or less than the maximal contraction attainable with more aggressive waveforms. The X26 has been tuned to deliver a contraction roughly 5% greater than the M26 – a level still well below even 50% of the maximal contractions found in the AFRL study.

While the TASER device-induced contractions are sufficient to interfere with and impair voluntary movement and cause incapacitation in the majority of applications, they are still within the normal operating range of voluntary muscle movements associated with strenuous activities such as weight lifting, wrestling, or other athletic, sports, or exertion activities.

TASER Device Outputs and Comparisons

Figure 17 is a graph depicting the current output of a single AIR TASER 34000 pulse compared to a TASER M26 pulse. The vertical axis is the magnitude of electric current. The horizontal axis is time, measured in microseconds (1 microsecond (µs) = 0.000001 seconds).


Figure 17 Comparison of Current Output of AIR TASER 34000 and TASER M26

Note that for a very brief period of time (about one microsecond), the peak current output from the AIR TASER 34000 reaches about 8 amperes (remember that a strong static shock can reach a peak of 30–37.5 amperes). However, the duration of the primary phase of the impulse is extremely short – roughly five microseconds. This is about 1/200,000th of one second. To give you an idea of how short this pulse duration is: if you stacked 200,000 sheets of standard copier paper, the stack would be roughly 50 feet tall. If this stack of paper represented just one second in time, the duration of the primary phase of the AIR TASER 34000 pulse would be the width of just one piece of paper from the 50-foot-tall stack of 200,000 sheets!

Because the pulse duration is so extremely short, the amount of electrical charge actually delivered is quite small. Consider if you turn on a faucet, even at a very high flow rate, but you turned it back off after 0.000005 seconds. Even though the flow rate for that moment in time might be high, a very small amount of water would actually have time to flow out – probably just a drop.

In looking at the same chart again, since the vertical axis is the flow rate and the horizontal axis is time, the amount of actual charge delivered can be calculated by taking the area under the curve.

In the case of the AIR TASER 34000, the charge in the primary pulse is roughly 0.00003 coulombs (C) (or 30 microcoulombs [µC]). The charge in the entire pulse

E+00 1.00E-05 2.00E-05 3.00E-05 4.00E-05 5.00E-05 6.00E-05 7.00E-05 8.00E-05 9.00E-05

M26 Taser Current [A] M34000 Taser Current [A]

Time (sec)

Cur

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[A]


(including both the positive and negative phases) is roughly 70 microcoulombs (µC). However, it is the charge in the first phase that appears to be the most important for causing peripheral nerve stimulation. Once the current changes polarity, it is actually shifting charge in the opposite direction. Hence, if the nerve cell has not reached its action potential threshold during the first phase, the second negative phase actually works against it. Therefore, it is the charge in the primary phase that is most relevant. However, in the interest of conservatism for rating purposes, the entire charge delivered will be considered. Since the device pulses roughly 15 times per second it will deliver 70 microcoulombs (total rectified charge) * 15 pulses per second = 1,050 microcoulombs per second. Since current is the flow rate of charge, 1,050 microcoulombs per second = 1,050 microamperes = 1.05 milliamperes.

Since the pulse intensity from the AIR TASER 34000 was found to be insufficient to cause motor neuron mediated stimulation of muscle, a new pulse waveform was developed for the TASER M26. Note that the M26 delivers a pulse that is both taller and wider than the AIR TASER 34000. Accordingly, the total charge delivered from the M26 pulse is also higher, roughly 85 microcoulombs (µC). At a nominal pulse rate of approximately 20 pulses per second, this equates to an average rectified current of 3,600 microamperes = 3.6 milliamperes (0.0036 A).

Due to all the equipment law enforcement officers must carry, it was reportedly difficult for officers to fit the TASER M26 on their duty belts for full-time carry. Accordingly, the company set out to develop a smaller TASER device that could still cause a similar amount of motor-nerve mediated muscular incapacitation. The result was a more complex waveform using “Shaped Pulse™” Technology. (For more details on Shaped Pulse™ Technology, see TASER Training CD/DVD version 10+.) A new waveform developed using Shaped Pulse Technology, which delivered a comparable amount of charge to the waveform from the TASER M26, was implemented in a new device called the TASER X26, introduced in May of 2003.


Electrical Waveform Comparison of M26 and X26

-10

-5

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0 10 20 30 40 50 60 70 80 90 100Time [us]

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X26 Waveform M26 Waveform

Figure 18 Comparison of Current Output of ADVANCED TASER M26 and TASER X26

Note that the TASER X26 uses a lower peak current than the ADVANCED TASER M26, but a longer pulse duration. As a result, the X26 delivers a roughly comparable amount of electrical charge in each pulse. In laboratory experiments, the output of the TASER X26 was designed to cause approximately 5% stronger muscle contractions than the M26. The X26 delivers roughly 100 microcoulombs (µC) per pulse, at a pulse rate of 19 pulses per second (pps), for an average rectified current of 2,100 microamperes (µA) or 2.1 milliamperes (mA) (or 0.0021 A). (Note, the primary phase of the X26 is actually negative in polarity compared to the main pulse – however most of the charge delivered is of the same polarity, one of the reasons that the X26 waveform is more efficient.)

These patented pulse waveforms have proven highly effective at incapacitating even the most aggressive subjects while minimizing the risk of serious adverse effects. Due to the extremely short pulse durations used in TASER pulses, the charge per pulse and average current are miniscule when compared to continuous outputs such as AC currents from a wall outlet, industrial equipment, or power lines.


TASER Risk Benefits

TASER device deployments have been shown to dramatically reduce officer and suspect injuries. More information can be located on the field use reports, risk analysis PowerPoint presentations, published studies, etc.

Use of Force DataOrange County Sheriffs, Florida

0

100

200

300

400

500

600

Year

# o

f In

cid

en

ts

Chemical 300 263 221 154

Physical 78 75 52 70

Impact Rounds 0 1 2 -

K9 62 60 48 70

Batons 27 21 13 12

TASER 0 3 228 482

1999 2000 2001 2002

TASER

Firearms Use13

0

5 4

02468

101214

# o

f In

cidents

46%46%Topeka PD

40%83%Cape Coral PD

19 “saves”7959%Charlotte-Mecklenburg

78%80%Orange County SO

25%14 “saves”24%23%Columbus PD

18%Omaha

54%67%Phoenix PD

32%80%53%Austin PD

50%40%70%Cincinnati PD

Force ComplaintsLethal ForceSuspect

InjuriesOfficer InjuriesDept

Miami and Seattle: Over 12 Months without a Lethal Force ShootinMiami and Seattle: Over 12 Months without a Lethal Force Shootingg

Real World TASER Program Results

80%

16%

78%

36%

78%

20%

60%

21%

45%

11%

29%

18%

5%

29%

0%0%0%

10%

20%

30%

40%

50%

60%

70%

80%

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TAS

ER

Force Type

Comparison of InjuriesTASER Technology Reduces Injuries

SuspectInjured

OfficerInjured /Affected

Source: Study of Use of Force at Los Angeles Police Department, Capt. Greg Meyer. Statistics are for 7-Watt TASER technology deployed at LAPD.Original Study Available at http://home.earthlink.net/~gregmeyer/injury.html on the internet.

Risk vs. Benefit

Figure 19 Examples of TASER Risk Benefits

DEGREE OF CERTAINTY

While many of the statements in this document are factual in nature, or directly out of high school sciences revisited, any expert opinions are to a reasonable degree of scientific, medical, and/or professional certainty.

An Introduction to TASER® Electronic Control Devices, History ...

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