TASER ECDs, History, Electricity, Electrical Stimulation, Electrical

Brief Introduction to TASER®
Electronic Control Devices,
History, Electricity, Electrical Stimulation,
Electrical Measurements, and the Human Body
By Rick Smith and Michael Brave
TABLE OF CONTENTS
INTRODUCTION .................................................................................................. 1 Early Medical Considerations of Electricity ........................................................ 2 WHAT IS ELECTRICITY? ..................................................................................... 4 Hoover Dam Water Analogy .............................................................................. 5 Water Hose Analogy ......................................................................................... 5 Joule (J) – Water Analogy ................................................................................. 6 BASIC ELECTRICAL PRINCIPLES (MIDDLE SCHOOL PHYSICS 101) ............. 7 Power Supply Limitation .................................................................................... 8 50 kilovolt (kV) from A Battery of Small Cells? .................................................. 8 WHY TASER ECDS ARE HIGH VOLTAGE ......................................................... 8 50,000 V DO NOT ENTER THE BODY ................................................................ 9 IT’S NOT THE VOLTS, IT’S THE DELIVERD CHARGE THAT MATTER THE
MOST ................................................................................................................... 9 TASER CURRENT DOES NOT LAST LONG ENOUGH TO CREATE A
SUBSTANTIAL RISK OF AFFECTING THE HUMAN HEART ........................... 11 Limited by the Very Limited Battery Power Supply .......................................... 13 Power Limited by Wire Conductors ................................................................. 13 Power Limited by Delivery ............................................................................... 13 In Summary ..................................................................................................... 15 Average Current vs. Root Mean Square (RMS): ............................................. 15 Average Current .............................................................................................. 15 For TASER ECDs RMS Calculations Do Not Provide an Accurate Picture ..... 15 Average Current Relevant to TASER ECDs .................................................... 15 Comparison to International Safety Standards ................................................ 16 2002: TASER Tried Using RMS Calculations (Learning from Experience) ..... 16 BASIC TASER ECD OPERATING PRINCIPLES ............................................... 16 Telephone Network Communication Analogy ................................................. 19 Effects of Repeated Pulses on Muscle Tension .............................................. 20 Drive Stun graphic ........................................................................................... 20 BRIEF HISTORY OF TASER ECD TECHNOLOGIES........................................ 21 1967 – NASA Scientist Jack Cover’s TASER TF-76 ....................................... 21 Tasertron Emerged ......................................................................................... 21 1980s: Studies and Risk Utility Comparisons .................................................. 22 Early 1990s: The Need for Non-Firearm Self-Defense .................................... 22 ICER Corporation Formed ............................................................................... 22 TASER 34000 – 2nd Generation TASER Device ............................................. 22 1994: TASER 34000 Limited to Non-Law Enforcement .................................. 23 Nov. 1995: The Czech Experience: Original TASER Devices Did Not Get the
Job Done! ........................................................................................................ 23 1996: ADVANCED TASER M26 ECD Is Born ................................................. 23 Stratbucker Testing ......................................................................................... 24 TASER M26 ECD Developed .......................................................................... 25 TASER M26 ECD Emerges – 3rd Generation TASER Device ......................... 25 Medical and Scientific Research ..................................................................... 25 Late 1999: ADVANCED TASER M26 ECD ..................................................... 25 Rev: G
July 14, 2012
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May 2003 – TASER X26 ECD Debuted – 4th Generation TASER Device ....... 26 2007 – TASER eXtended Range Electronic Projectile (XREP™) – 5th
Generation TASER Device .............................................................................. 26 TASER C2™ ECD........................................................................................... 26 TASER X3™ ECD ........................................................................................... 26 TASER X2™ ECD ........................................................................................... 26 BASIC TASER ECD OPERATIONS ................................................................... 27 Transformers: Analogy: An Electrical Lever .................................................... 27 THE TASER ECD CIRCUIT: AN ILLUSTRATIVE LOOK .................................... 28 Basics of Nerve and Muscle Stimulation ......................................................... 29 The Neuromuscular Junction .......................................................................... 30 Tetanus ........................................................................................................... 31 How the TASER ECD Does What It Does to the Body .................................... 31 TASER ECD Outputs and Comparisons ......................................................... 33 TASER ECD Risk Benefits .............................................................................. 36 DEGREE OF CERTAINTY ................................................................................. 36 Rev: G
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TABLE OF FIGURES
Figure 1 Electrotherapy 1785. From Adams (1785). ............................................. 2 Figure 2 Galvani (1790) From Beard & Rockwell 1878. ........................................ 2 Figure 3 Let-go testing. From Dalziel, 1972. ......................................................... 3 Figure 4 Electricity is the Flow of Electrons through a Conductor ......................... 7 Figure 5 Mother and Daughter Experience up to 20 Million V from a Van de Graff
Generator ............................................................................................................ 10 Figure 6 Common U.S. Wall Outlet and TASER ECD Waterfall Analogy
Comparison ........................................................................................................ 11 Figure 7 Average Current Comparison ............................................................... 12 Figure 8 Maximum Power Battery of (8 AA) Alkaline Cells ................................. 14 Figure 9 M26 ECD Battery: Alkaline vs. NiMH Cells 10/16/06 ............................ 14 Figure 10 Neurons. Fig. 3.1 of Reilly, 1998. ........................................................ 17 Figure 11 Sensory Receptors. Fig. 3.16 of Reilly (1998). ................................... 18 Figure 12 TASER ECDs Stimulate the Motor and Peripheral Nervous Systems
with Pulses Similar to Those Used by Nerves to Communicate ......................... 19 Figure 13 Fig. 3.22 from Reilly, 1998. ................................................................. 20 Figure 14 ECD drive stun graphic illustration. ..................................................... 20 Figure 15 Understanding Transformers Analogy ................................................ 27 Figure 16 An Illustrative Representation of the TASER M26 ECD Circuit ........... 28 Figure 17 Air Force Research Lab Tests Show TASER M26 ECD Muscle
Contractions at 40% or less of Maximum Contraction Force .............................. 32 Figure 18 Comparison of Current Output of AIR TASER 34000 and TASER M26
ECD .................................................................................................................... 33 Figure 19 Comparison of Current Output of TASER M26 ECD and TASER X26
ECD .................................................................................................................... 35 Figure 20 Examples of TASER ECD Risk Benefits ............................................. 36 TABLE OF TABLES
Table 1 Electricity/Water Analogy ......................................................................... 7 Rev: G
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INTRODUCTION
The purpose of this appendix is to provide a brief basic partial overview of the
fundamental operating principles and concepts of how TASER1®-brand Electronic
Control Devices (ECDs) 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,
cellular 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 historical middle school and
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. This electricaphobia is often fueled by many
electrical myths.
It is important to keep in mind that all electricity is not the same. Just like not all
balls are the same, nor is all water:
Balls: 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 all quite different, with very differing effects in their
capacity to cause injury or death. 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
volt (V) alternating current (AC) outlet, and a handheld, small batterypowered ECD would be approximately equivalent to a tennis ball.
Water: Just as all water is not the same – water can be in the form of solid (ice),
liquid, or gas (steam). The effects of each form can have on a person is
very different, especially based upon how the water is delivered. As a
simple example, drinking water is good for the body, a torrential downpour
or drowning in water can be deadly.
It is also important to note that nothing is risk free. Anything that exists can cause
serious injury or death. Just like, it is well known to law enforcement officers that
“[a]lmost every use of force, however minute, poses some risk of death.”2
1
AIR TASER, M26, X26, X3, XREP, Shockwave, X2, AXON, AXON Flex, are
trademarks of TASER International, Inc. TASER® and ADVANCED TASER® are
registered trademarks of TASER International, Inc.
2
Garrett v. Athens Clarke County, 378 F.3d 1274, 1280, n.12 (11th Cir. 2004).
Rev: G
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Page 1
Early Medical Considerations of Electricity
Electricity, its science and physics, its properties, its uses, its medical and
engineering parameters, and its effects on animals and humans has been widely
and extensively studied worldwide for well over 200 years.
Figure 1 Electrotherapy 1785. From Adams (1785).
Figure 2 Galvani (1790) From Beard & Rockwell 1878.
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Figure 3 Let-go testing. From Dalziel, 1972.
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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 water through a conduit
analogy may help to visualize and understand some of the basic principles of
electricity that many students learn about in middle school and high school
science classes.
Basically, there are five (5) key elements to characterize electricity: Voltage,
Current, Power, Energy, and Charge.
VOLTAGE3 (measured in “volts” and symbolized by “V”): also called
electromotive force, 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).

The X26 ECD has a mean voltage per pulse was 580.1 volts (V), with an
average peak main phase voltage of 1899.2 V.4
CURRENT (measured in “amperes” and symbolized by “A” or “I”): is
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 (s). One ampere (A) is
the flow of 1 coulomb (C) of electrons in 1 second (s).
3
Voltage, expressed in volts (V), (often 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.
4
Dawes DM, Ho JD, Kroll MW, Miner JR. Electrical Characteristics of an Electronic
Control Device Under a Physiologic Load: A Brief Report. Pacing Clin Electrophysiol.
Mar 2010;33(3):330-6.
Rev: G
July 14, 2012
Page 4

The X26 ECD has a mean current per pulse was 0.97 amperes (A) and
average peak main phase current of 3.10 A.5 The X26 ECD has an
average, aggregate, or actual current of approximately 0.0019 A or 0.0015
- 0.0026 A.
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 s.
The water analogy would be the water flow rate measured in gallons per second.
Electric current is measured in amperes (A). One ampere (A) is equal to a flow
rate of 1 coulomb (C) (approximately 6,240,000,000,000,000,000 electrons) per
second (s). While the number of electrons in a coulomb 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, electric charge, measured in C, would be the total
amount of water that has flowed, measured in gallons.

The X26 ECD has a main phase charge or 80 - 135 microcoulombs (µC)
per pulse.
POWER (measured in “watts” and symbolized by “W” or “P”): is the SI
derived unit of power, equal to one joule (J) of energy per second (s). 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.
5
Dawes DM, Ho JD, Kroll MW, Miner JR. Electrical Characteristics of an Electronic
Control Device Under a Physiologic Load: A Brief Report. Pacing Clin Electrophysiol.
Mar 2010;33(3):330-6.
Rev: G
July 14, 2012
Page 5
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 equals (=) current times pressure
(or height). In an electrical device, power (W) equals (=) electric current (A) times
(x) voltage (V). One horsepower (hp) is equal to 746 watts (W). So, a high
performance, 300-horsepower (hp) car engine produces 223,800 watts (W).

The X26 ECD delivers 1.8 - 2.3 watts (W).
ENERGY (measured in joules (J) and symbolized by “E”): 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
electric Current (A) and Charge (C). Electric current is the flow rate of Charge
(C). Power (W) is the Flow Rate of Energy. Energy is measured in joules (J).
The joule (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 an electric 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.

An X26 ECD delivers 0.095 – 0.125 joules per pulse.
Joule (J) – Water Analogy
In the water analogy, think of a joule (J) 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
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charge – similar to what a TASER ECD delivers). One joule (J) is also 0.2388
calorie6 (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
Voltage (in volts [V])
Current (SI base unit – A)
Charge (SI base unit – C)
Power (V)
Voltage (V) x Current (A)
Energy (J)
Power (W) x Time (s)
Resistance
ECD Current Pulses
“WATER ANALOGY”
“WATER UNIT”
Volt (V)
Ampere (A)
Coulomb (C)
Watt (W)
Pressure
Water Flow Rate
Total Water Volume
lbs / in2 or PSI
Gallons per Second
Total Gallons
Flow Rate x Pressure
Joule (J)
Water Balloon
Ohms (Ω)
PPS
Diameter of Water Hose
Bursts of Water
Flow Rate x Pressure
x Time
Centimeters (cm)
Water Balloon
BASIC ELECTRICAL PRINCIPLES (MIDDLE 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, completes a
circuit in probe mode by flowing from the ECD through the first wire, through the
probe, into the target, to the other probe, into the other wire, returning back to the
ECD - completing the circuit. Thus, the electricity must flow through a circuit, and
must return to the power source. In this respect, electricity seems different than
the flow of water – which simply flows on one direction (often) 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 order to deliver an
electrical charge. In some cases, such as the TASER ECD, the source is the
energy cells, or multiple cells in a battery (of cells) (each cell commonly
inappropriately referred to as a “battery”). In other electrical circuits, such as your
home, the source of electricity is usually the local power station that generates
the power.
6
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.
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Power Supply Limitation
In any given electric circuit, the total power is limited by several factors including
the power supply. In the case of the TASER ECD, the power supply is the very
limited power consisting of a battery of cells. Hence, the power delivered by the
TASER ECD cannot exceed the power supplied by the battery of eight AA
penlight cells (AA cells are used in the TASER M26™ ECD (M26 ECD) – the
power level is even smaller in the TASER X26™ ECD (X26 ECD), with its two
three-volt digital camera-type cells (same batteries as used by a Nikon® F6
camera).
50 kilovolt (kV) from A Battery of Small Cells?
A common question often asked is, “How can the TASER ECD generate up to
50,000 peak arcing volts (V) output from the very limited power of eight AA cells
or two 3 V cells?” The answer is, the TASER ECD uses transformers and the
principles of physics that define the relationship between power, current, and
voltage to generate the high voltage arcing 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) ECD only 6,400 to 9,700 V
peak, approximately 3400 V average over the duration of the pulse, enter the
body, or approximately 1.44 V average (one-second baseline)7.

From the TASER X26 ECD the peak voltage delivered to the body is about
1900 (1,400 to 2,520)8 volts9 (V) and is present for a very short time, while the
average voltage delivered to the body throughout the X26 ECD pulse is about
600 V, or approximately 1 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. And, means nothing as far
as physiologic effect of stimulation.
WHY TASER ECDS 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 electrical energy. To be
able to jump up to approximately 40 millimeters (mm), or 1.6 inches, combined
7
For full electrical characteristics, calculations, most accurate numbers, etc. please refer
to the most current TASER ECD specifications and electrical characteristics documents.
Numbers stated herein may be approximations and may vary based upon load, etc..
8
TASER X26 ECD electrical characteristics.
9
Dawes DM, Ho JD, Kroll MW, Miner JR. Electrical characteristics of an electronic
control device under a physiologic load: a brief report. Pacing Clin Electrophysiol.
2009;33(3):330-336.
Rev: G
July 14, 2012
Page 8
air gap. This allows for minimizing the discharge velocity of the probes from the
TASER cartridge.
A TASER ECD 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 ECD uses high pressure
(high voltage) to eject electrons from the tips of the darts (probes) across a gap
of up to approximately 1.6 inches (40 mm) 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 ECD do not have to penetrate, or
even touch the skin, to deliver electrical energy. The high voltage allows the
TASER ECD electrical output to jump through up to approximately 1.6 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) (0.0397008 inches) air gap. Accordingly,
the TASER ECD must generate a peak of up to 50,000 V to jump across a 40
mm (roughly 1.6-inch) air gap.
Without the high peak arcing voltage, the TASER ECD 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 ECD far more intrusive, more likely to penetrate deeper into the
body, and physically much larger. In this respect, the usage of high voltage
allows TASER to make the ECD a safer, less intrusive tool.
50,000 V DO NOT ENTER THE BODY
Even though the M26 ECD, ADVANCED TASER M18 and M18L ECDs, TASER
X26 ECD, TASER X3™ ECD, TASER C2™ Personal Protector ECD, and
TASER X2 ECD have a 50,000 peak open circuit arcing voltage to jump the air
gap, none of these TASER ECDs delivers 50,000 V to a person’s body. The M26
ECD an average (one-second baseline) voltage of approximately 1.44 V, with a
peak loaded voltage of 9,700 V, and about 3,400 V average over the duration of
the pulse. The X26 ECD has an average (one-second baseline) voltage of about
1 V, with a peak loaded voltage of 1,900 V, and a 600 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 ECD 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
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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 delivered electric 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
electric 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 electric current flows.
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Wall Outlet
TASER ECD
Med Voltage: 110V
High Voltage: 5,000+ V
Continuous Current
Pulsed Current
High Current
Low Current
Danger: High
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 (comparing with an ECD)
travels thousands of feet to the ground it does not cause injury, while a very large
waterfall (comparing a lightning strike or high-current power line) travels a much
lesser distance but has much more force, and thus has a much higher risk of
causing injury/damage. Another example is a fire hose versus a garden hose, or
a common beverage drinking straw.
TASER CURRENT DOES NOT LAST LONG ENOUGH TO CREATE A
SUBSTANTIAL RISK OF AFFECTING THE HUMAN HEART
Consider static electricity. Everyone has received at least one strong static
electricity shock in their lifetime. The typical electric 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 been documented in the published peer-reviewed literature to
have 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 cardiac arrhythmia) after a static shock.10
The electric 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
10
Screnock T. “Static Electricity Stops a Recalcitrant Arrhythmia.” Ann Intern Med. 130,
no. 1 (January 5, 1999):78.
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electrical devices we use today. Meaning, if a cellular phone, a pager, computer,
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 average electric current output from a wall outlet is approximately
4,000 times higher current potential than the average current from a handheld,
battery-powered TASER ECD.
Figure 7 Average Current Comparison
To appreciate TASER technology, one needs to only imagine a similar, very
short shock (actually involving less peak electric current) but delivered repeatedly
15 to 25 times per second. This can immobilize a violent or resisting subject, but
with very low probability of risk of negatively affecting the heart.
The TASER X26 ECD is programmed to deliver a very short electrical pulse of
approximately 100 microseconds (µs) duration with about 100 microcoulombs
(µC) of electrical charge at about 19 pulses per second (PPS) for 5 seconds
(s)11. The peak voltage delivered to the body is about 1,900 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.12 The average,
aggregate, or actual current from the X26 ECD is approximately 2 milliamperes
(mA) (or 0.002 amperes).
11
This initial 5-second TASER X26, M26, X3, or X2 ECDs discharge can be interrupted
at any time simply by the ECD operator activating the TASER ECD’s safety.
12
http://www.web-ee.com/primers/files/ESD_Tutorial.pdf
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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 ECD, this is the battery of cells). TASER makes a sophisticated
ECD, 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 ECD
and the target. The TASER ECD wires are very small (127 microns in diameter,
about the size of some human, hair, and are easily broken with a tensile strength
of about two pounds), and are not capable of delivering large electric currents
that would require wires such as those 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 electric 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).
For example, if the battery of cells in a TASER ECD could output a maximum of
50 W (which it cannot; the X26 ECD delivers 1.8 to 2.3 W at 19 PPS), the table
below would illustrate the maximum voltage and current it could generate:
Power
50 W
50 W
50 W
50 W
=
=
=
=
Voltage
5V
50 V
500 V
50,000 V
x
x
x
x
Current
10 A
1A
0.1 A
0.001 A
These numbers are for illustration purposes only, 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 electric
charge, current, or energy, is the key measurement for how electricity affects the
body.
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Actually, an M26 ECD 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 NiMH
10/16/2006
18.00
16.00
14.00
Pulse Rate
12.00
10.00
8.00
6.00
4.00
2.00
00
:0
5
00
:2
0
00
:3
5
00
:5
0
01
:0
5
01
:2
0
01
:3
5
01
:5
0
02
:0
5
02
:2
0
02
:3
5
02
:5
0
03
:0
5
03
:2
0
03
:3
5
03
:5
0
04
:0
5
04
:2
0
04
:3
5
04
:5
0
05
:0
5
05
:2
0
05
:3
5
05
:5
0
06
:0
5
06
:2
0
06
:3
5
06
:5
0
07
:0
5
0.00
-2.00
Elapsed Time (mm:ss)
Duracell Ultra Alkaline
Pulse Rate
Energizer NiMH 1700maH
Pulse Rate
Figure 9 M26 ECD Battery: Alkaline vs. NiMH Cells 10/16/06
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In Summary


Voltage is the pressure that determines how far an electric arc can jump.
Delivered electric charge, 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. In the case of a TASER ECD the “average” current is
synonymous with the “aggregate” or “actual” current.
For TASER ECDs RMS Calculations Do Not Provide an Accurate Picture
RMS current is calculated as an approximation for the electric current used when
analyzing continuous alternating currents (AC), as opposed to pulsed current
(e.g. the short duration pulses produced by TASER ECDs). 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 would 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 ECDs
The average electric current is more relevant to measuring TASER ECD outputs
and far more relevant to neural stimulation, rather than heating (or continuous
Rev: G
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Page 15
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).
Comparison to International Safety Standards
The IEC has set 35 mA as a safe level of utility (50/60 hertz (Hz)) electrical
current for avoiding the cardiac risk of ventricular fibrillation (VF) induction
(electrocution).13 According to the literature, rapid short pulse stimulation has the
same risk of VF induction as does utility power frequencies at a current of 7.4
times higher than the aggregate (or actual or average) current of the rapid
pulses. The X26 ECD delivers 19 pulses per second at a charge of about 100 µC
(microcoulombs) per pulse.14 This gives an aggregate current of 1.9 mA which
corresponds to a utility power current of 14.1 mA = 1.9 mA • 7.4. This is seen to
be less than half of the IEC VF safety level and thus accepted international
standards.
2002: TASER Tried Using RMS Calculations (Learning from Experience)
Back in 2002, TASER tried using RMS to attempt to measure TASER ECD
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 ECD for
comparison to those electrical safety standards that used RMS currents.
BASIC TASER ECD OPERATING PRINCIPLES
The intended purpose of an ECD is for self defense (and defense of others) and
to assist with capturing, controlling, and (when necessary) restraining a person
while minimizing risk (compared to most similar force tools) of death or serious
injury. Prior less-lethal weapons function by merely causing pain or destructive
injury.
13
International Electrotechnical Commission. Household and similar electrical
appliances – Safety – IEC 60335-2-76: Particular requirements for electric fence
energizers. 2.1 ed: IEC, Geneva, Switzerland; 2006.
14
Dawes DM, Ho JD, Kroll MW, Miner JR. Electrical characteristics of an electronic
control device under a physiologic load: a brief report. Pacing Clin Electrophysiol. Mar
2010;33(3):330-336.
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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, in
serious psychological distress15, under the influence of drugs16, 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 Ventura jail incident). The proprietary Neuromuscular Incapacitation
(NMI) technology in TASER ECDs is designed to not solely rely on pain or on
intended destructive injury for its incapacitating effect(s). Rather, the TASER
ECD, in probe deployment mode, is designed to use short-duration, pulsed, lowenergy 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
15
People in serious psychological distress (SPD) increasing annually (2004) 21,400,000
(9.9% of adults); (2007) 23,400,000 (10.9% of adults).
16
Drug abuse is increasing annually: (2004) 19,100,000 current illicit drug abusers
(7.9% of population); (2006) 20,357,000 current illicit drug abusers; and (2009)
21,800,000 current illicit drug abusers age 12 and older (8.7% of population); and (2004)
1,997,993 drug caused emergency room visits.
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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 ECDs. TASER ECDs are designed to 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 ECDs 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.
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Figure 12 TASER ECDs Stimulate the Motor and Peripheral Nervous Systems with Pulses
Similar to Those Used by Nerves to Communicate17
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 ECDs are designed to 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.
17
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 ECD 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.
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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 ECDs have a
pulse rate of up to
approximately twenty (20
± 25%) pulses per second
(pps).
Drive Stun graphic
In drive-stun mode the electrical path of the ECD is between the two (2) fixed
electrodes on the front of the ECD or an expended cartridge. When the ECD
comes into drive-stun contact with a subject the delivered charge is pain
compliance.
Figure 14 ECD drive stun graphic illustration.
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BRIEF HISTORY OF TASER ECD TECHNOLOGIES
1967 – NASA Scientist Jack Cover’s TASER TF-76
John H. “Jack” Cover was the original inventor of TASER ECD technology. Mr.
Cover was the Chief Scientist at North American Aerospace when it was the
prime contractor for the National Aeronautics and Space Administration’s
(NASA’s) Apollo Moon Landing program. Jack was a dedicated physicist who in
the 1960s read about President Lyndon Johnson’s Blue Ribbon Crime
Commission report that urged the development of non-lethal weapons
development to combat airplane hijacking, riots, and civil unrest occurring at that
time. Jack’s quest to develop his first ECD began in 1966 when he developed
ECD working models and named them after his favorite childhood character:
Tom A. Swift and his Electric Rifle (TASER).
The original TASER device (the TF-76) was launched in the mid 1970s by
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
possessed or used by law enforcement agencies. While the Title 2 weapon
classification did not excessively adversely affect law enforcement agencies
acquisition and use of the early TASER devices, it did prevent most civilians from
acquiring, possessing, or using the devices. Shortly after the TF-76 was
classified as a Title 2 weapon, TASER Systems (the company that made the TF76) 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 (greater than the X26 ECD) 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.
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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 killing, 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 less injuries force
option alternatives, many people would choose lower risk weapons instead of
firearms – 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 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 could
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
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glow under a black light, thus making them 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 noncompete 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 ECD 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 ECD. 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.
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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 effect 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 of the test animal.
Dr. Stratbucker’s experiments corroborated earlier findings in consulting reports
and peer review journals18 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. The study also showed that the animals
physiologic and biomarker monitoring remained physiologically stable throughout
the testing, even though there were many ECD discharges delivered to the test
subject.
Due to Dr. Stratbucker’s qualifications and extensive knowledge and history with
electronic devices he later became TASER’s Medical Director, and served in that
capacity until about 2010. Dr. Stratbucker holds the title of Emeritus Medical
Director.
18
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.
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TASER M26 ECD Developed
Mr. Smith was proud to have led the development team, designed the test
methodology used to develop the TASER M26 ECD, and was the listed inventor
on the patent for the electrical waveform of the M26 ECD.
TASER M26 ECD 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 ECD was designed to have the capacity 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 ECD medical, scientific, electrical,
and engineering literature was extensively researched with regard to electrical
energy, charge, 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 ECD
The ADVANCED TASER M26 ECD was launched in late 1999, with an initial
shipment of thirty (30) M26 ECDs 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. (TASER) to signify the company
had more than just the one AIR TASER product. The TASER M26 ECD was
adopted by thousands of law enforcement agencies, and was hailed as a stateof-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 ECD implemented a new accountability control technology – the
dataport. The dataport is a function wherein the M26 ECD would record the time
and date of every five (5) second discharge trigger pull19 in order to allow law
enforcement agencies to monitor use of the device – another use-of-force
accountability break through.
19
Also, the M26 ECD records a datapoint entry with each five (5) seconds of continuous
ECD discharge.
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May 2003 – TASER X26 ECD Debuted – 4th Generation TASER Device
In 2003, TASER introduced the TASER X26 ECD. The X26 ECD 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 ECD to be packaged in a form factor that was
approximately 60% smaller and 60% lighter than the M26 ECD. However, the
X26 ECD design was tuned in laboratory testing to deliver an incapacitating
effect that caused muscular contractions approximately 5% stronger than those
of the M26 ECD.
The TASER X26 ECD 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 is designed to deliver similar Neuro Muscular Incapacitation (NMI)
bio-effect as the handheld TASER X26 ECD, but can be delivered to a distance
of approximately 65 feet (20 meters [m]), combining blunt impact with fieldproven TASER NMI. The XREP was discontinued for law enforcement use in
May 2012.
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.
TASER X3™ ECD
The TASER X3 ECD came to market in late 2009 and is revolutionary in its
capabilities. This three (3) shot ECD has numerous technologically advanced
features, including, but not limited to: Trilogy Logs (which includes the ability to
determine the duration of delivered electrical charge to the target), ability to
provide intimidation arcing without removal of the cartridges, smart cartridges,
dual LASER aiming, strong user programmable capabilities, continuous
monitored electrical charge delivery, etc.
TASER X2™ ECD
The TASER X2 ECD came to market in 2011. This two (2) shot ECD has many
of the numerous technologically advanced features of the X3 ECD, including, but
not limited to: Trilogy Logs (which includes the ability to determine the duration of
delivered electrical charge to the target), ability to provide intimidation arcing
without removal of the cartridges, smart cartridges, dual LASER aiming, strong
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user programmable capabilities, continuous monitored electrical charge delivery,
etc.
BASIC TASER ECD OPERATIONS
It is common for people to ask, “How can the TASER ECD generate 50,000 V
from 12 V or less at the battery of cells (for the TASER M26 ECD)?” The answer
is that TASER ECDs 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 15 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 electrical current at 10 volts are delivered
into this transformer, 1 ampere of current at 20 volts will be the output. (Note that
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in the real world, transformers are not 100% efficient, so the actual output will be
slightly less than the input.)
THE TASER ECD CIRCUIT: AN ILLUSTRATIVE LOOK
The battery of power cells is the power supply in any TASER ECD. 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 ECD 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 16 An Illustrative Representation of the TASER M26 ECD 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, an average of 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,
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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 electrical current drops
again to an even lower output current.
One important note – the 50,000 volts is a peak potential voltage, or open circuit
arcing 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 ECD 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 1.6 inches (or 4 mm) 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 ECD, the maximum voltage delivered across the
body of the target is about 6,400-9,700 volts, with only about 2 volts average
(one-second baseline). In the case of the TASER X26 ECD, the maximum
voltage delivered across the body of the target is about 1,400 to 2,520 volts, with
only about 1 volt average (one-second baseline).
The big picture from this illustrative look at the TASER ECD 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.
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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 very basic 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 millivolts (mV, or thousandths of a volt)), 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, or thousandths of a second). 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
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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 electric 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 muscle 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 ECD Does What It Does to the Body
TASER ECDs 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 electrical 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 handheld TASER M26 ECD, X26 ECD, X3 ECD, and X2 deliver a similar
train of electrical pulses, also at approximately 15–25 pulses per second.
However, the M26 ECD and X26 ECDs deliver more electrical charge in each
pulse. This higher delivered electrical 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
ECD 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).
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The mechanism of stimulation from the TASER ECD is primarily 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 neuromuscular junction (similar to curare). Before the drug
administration, the application of the TASER ECD caused significant muscular
contractions. After the drug administration, the TASER ECD 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 17 Air Force Research Lab Tests Show TASER M26 ECD 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 ECD could be increased to more than 250% of the level of contraction from
the field production M26 ECD. Accordingly, the M26 ECD generates a muscle
contraction approximately 40% or less than the maximal contraction attainable
with more aggressive waveforms. The X26 ECD has been tuned to deliver a
contraction roughly 5% greater than the M26 ECD – a level still well below even
50% of the maximal contractions found in the AFRL study. Dr. James Sweeney’s
paper states that “[s]imulated isometric forces evoked at 19 Hz with either [M26
ECD or X26 ECD] device are moderately intense (about 46% of maximal).”20
While the TASER ECD is designed to induced contractions that 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 strenuous athletic, sports, or exertion activities.
20
Sweeney J. Theoretical Comparisons of Nerve and Muscle Activation by
Neuromuscular Incapacitation Devices. Conf Proc IEEE Eng Med Biol Soc. 2009; 1:
3188-3190.
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TASER ECD Outputs and Comparisons
Current [A]
Figure 18 is a graph depicting the electrical current output of a single AIR TASER
34000 pulse compared to a TASER M26 ECD pulse. The vertical axis is the
magnitude of electric current. The horizontal axis is time, measured in
microseconds (1 microsecond (µs) = 0.000001 seconds).
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
Time (sec)
M26 Taser Current [A]
M34000 Taser Current [A]
Figure 18 Comparison of Current Output of AIR TASER 34000 and TASER M26 ECD
Note that for a very brief period of time (about one microsecond (or millionth of a
second)), the peak electrical 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.
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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 electrical 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] or millionths of a coulomb).
The electrical charge in the entire pulse (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 ECD pulses roughly 15 times per second
it will deliver approximately 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 ECD. Note that the M26 ECD delivers a
pulse that is both taller and wider than the AIR TASER 34000. Accordingly, the
total charge delivered from the M26 ECD 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 ECD on their duty belts for full-time
carry. Accordingly, the company set out to develop a smaller TASER ECD 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 relatively comparable amount of
charge to the waveform from the TASER M26, ECD was implemented in a new
device called the TASER X26 ECD, introduced in May of 2003.
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Electrical Waveform Comparison of M26 and X26
20
15
Current [A]
10
5
0
-5
-10
0
10
20
30
40
50
60
70
80
90
100
Time [us]
X26 Waveform
M26 Waveform
Figure 19 Comparison of Current Output of TASER M26 ECD and TASER X26 ECD
Note that the TASER X26 ECD uses a significantly lower peak electrical current
than the ADVANCED TASER M26 ECD, but a moderately longer pulse duration.
As a result, the X26 ECD delivers a roughly comparable amount of electrical
charge in each pulse. In laboratory experiments, the output of the TASER X26
ECD was designed to cause approximately 5% stronger muscle contractions
than the M26 ECD. The X26 ECD 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 ECD 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 ECD waveform is more efficient.)
These patented pulse waveforms have proven 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.
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TASER ECD Risk Benefits
TASER ECD deployments have been shown to reduce officer and suspect
injuries. More information can be located on the current versions of the field use
reports, risk analysis PowerPoint® presentations, published studies, etc.
Use of Force Data
Real World TASER Program Results
Orange County Sheriffs, Florida
# of Incidents
600
Dept
500
Cincinnati PD
R
SE
A
T
400
300
Austin PD
Orange County SO
CharlotteMecklenburg
100
Cape Coral PD
0
2000
300
263
Physic al
78
75
0
1
62
60
27
21
13
12
0
3
228
482
# of Incidents
1999
Chemic al
Impac t
K9
Batons
TASER
6
4
2
2001
52
13
Topeka PD
154
Omaha
70
2
 70%
 53%
 40%
 80%
 67%
 24%
 23%
 80%
 59%
 83%
 46%
 18%
Lethal Force
Force
Complaints
 50%
 32%
 54%
14 “saves”
 25%
 78%
 79
19 “saves”
40%
 46%
-
48
70
4
Year
5
2002
Firearms Use
221
Suspect
Injuries
Phoenix PD
Columbus PD
200
14
12
Rounds
10
8
Officer
Injuries
Miami and Seattle: Over 12 Months without a Lethal Force Shooting
Shooting
0
0
Comparison of Injuries
Risk vs. Benefit
TASER Technology Reduces Injuries
80%
78%
78%
80%
70%
60%
60%
50%
Suspect
Injured
45%
36%
29%
30%
20%
16%
20%
21%
29%
18%
11%
10%
Swarm
0% 0%
Chemical
Spray
Kick
Baton
Punch
Flashlight
0%
Misc. body
force
5%
Officer
Injured /
Affected
TASER
40%
Force Type
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.
Figure 20 Examples of TASER ECD Risk Benefits
DEGREE OF CERTAINTY
While many of the statements in this document are factual in nature, or directly
out of middle or high school sciences revisited, any expert opinions are to a
reasonable degree of scientific, medical, electrical, engineering and/or
professional certainty.
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