The purpose of this report is to provide a basic partial overview of the fundamental operating principles and concepts of how TASER-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.

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

Since we cannot physically see a flow of electrons through a conductor such as a metal wire, it is helpful to think of the analogy of water flowing through a pipe. This will help you visualize and understand some of the basic principles of electricity.

There are five key elements to characterize electricity: Voltage, Current, Power, Energy, and Charge.

VOLTAGE (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).

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, 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 of current through a resistance of one ohm).

CURRENT (measured in “amperes” and symbolized by “A” or “I”): Current measures the flow rate, how many electrons flow each second.

The water analogy would be the flow rate measured in gallons per second. Current is measured in amperes. One ampere is equal to a flow rate of 6,240,000,000,000,000,000 electrons per second, or 6.24 quintillion electrons per second. 6.24 quintillion electrons, while a very large number, is approximately equivalent to the number of water molecules in two (2) drops of water.

CHARGE (measured in “coulombs” and symbolized by “Q”): Is the total number of electrons moved over a given period of time.

In the water analogy, charge would be the total amount of water that has flowed, measured in gallons. The unit of charge is called the coulomb (C). One coulomb is equal to the number of electrons that flow in one ampere over one second, or exactly 6.24 quintillion electrons.

POWER (measured in “watts” and symbolized by “W” or “P”): Power is 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.

Consider the water analogy: 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.

In our water analogy, power is the rate at which energy is applied. Think of a fire hose, 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) do we produce high power. So, in a water wheel, power = current times pressure (or height). In an electrical device, power = current times voltage. One horsepower is 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) is like the relationship between Current (I) and Charge (Q). Current is the flow rate of Charge. Power is the Flow Rate of Energy. Energy is measured in joules (J). Hence, 1 watt of Power = 1 joule of Energy per second.

In the water analogy, think of a joule as a packet of energy. It could be the total energy from being hit with a fire 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 water balloon (this would correspond to brief pulses of electric charge – similar to what a TASER device delivers). One joule is also about ¼ of a calorie (as a measurement of heat created).

Electricity is the Flow of Electrons through a Conductor

Table 1 Electricity/Water Analogy

A very important aspect to understand about electricity is that it must always flow in a complete circuit. An electric current starts at a 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 due to pressure. But eventually it ends up in the ocean and is recycled through evaporation and rain back into the water supply. In 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 is the local power station that generates the power.

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 battery of cells. Hence, the power delivered by the TASER device cannot exceed the power supplied by the battery of eight AA penlight cells (in the TASER M26 – the power level is even smaller in the TASER X26, with its two three-volt photo-type cells).

A common question is, “How can the TASER device generate up to 50,000 peak arcing volts output from the very limited power of eight AA 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 a person’s body. From a TASER M26 only 5,000 V peak, 1500 V average over the duration of the pulse, enter the body, or 1.3 V average (one-second baseline). From the TASER X26 only 1,200 V peak, 400 V average over the duration of the pulse, enter the body, or 0.76 V average (one-second baseline). To say that 50,000 V is delivered to a person is sensationalistic and very misleading.

Before we talk about how we generate the high voltage, let’s talk about why we need to generate a high voltage. If we think about a garden hose, the higher the pressure, the farther the water will eject from the end of the hose. Similarly, the TASER device uses high pressure (high voltage) to eject electrons from the tips of the darts across a gap of up to approximately 2 inches of air and clothing and into a conductor such as the human body. Because of the high voltage generated, the darts from the TASER device do not have to penetrate or even touch the skin. The high voltage allows the TASER device electrical output to jump through up to 2 inches 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 volts of “pressure” to cause an electric arc to jump across a roughly one millimeter (mm) air gap. Accordingly, the TASER device must generate a peak of up to 50,000 volts to jump across a 50 mm (roughly two-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 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 us to make the TASER device a safer, less intrusive tool.

Even though both the ADVANCED TASER M26 and the TASER X26 have 50,000 peak open circuit voltage, to jump the air gap, neither TASER device delivers 50,000 V to a person's body. The ADVANCED TASER M26 has an average (one second baseline) voltage of 1.3 V, with a peak loaded voltage of 5,000 V, 1,500 V average over duration of pulse. While the TASER X26 has an average (one second baseline) voltage of 0.76 V, with a peak loaded voltage of 1,200 V, 400 V average over duration of pulse.

Many people ask how safe a TASER device can be since it generates a high (peak open circuit) voltage. In fact, voltage is not 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 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 transmitted through the body – i.e. the current (I) over time, or the total electric charge (Q) in very short duration discrete pulses, and not the high open circuit peak voltage.

Mother and Daughter Experience 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 device generates 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 and TASER ECD Comparison

Another way to look at this is the difference between rain fall and a very large waterfall (such as Niagara Falls). Although rain fall travels thousands of feet it does not cause injury, while a very large water fall travels a much less distance, yet, has much more force, and thus, can cause injury/damage.

Consider static electricity. Every one of us has received at least one strong static electricity shock in our lifetime. The typical current pathway is from a doorknob through a fingertip 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 the medical 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.[1]

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 pacemaker, etc. could not withstand a “strong static electricity” shock, then each of those electrical devices would soon be damaged. Thus, the International Electrochemical Commission (IEC) has defined a “strong static electricity” shock as having electrical characteristics of 30,000 volts, 30 amperes peak, and 1,000 ohms. (International Standard IEC-61000-4-2).

The maximum current output from a wall outlet is approximately 4,000 times higher current potential that a TASER electronic control device.

To appreciate TASER technology, one needs to only imagine a similar, very short shock  (actually involving less current) but delivered repeatedly 19 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' duration with about 100 microcoulombs of charge at 19 pulses per second for 5 seconds[2]. The voltage across 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.[3] The average current from the TASER X26 is approximately 2 milliamperes (0.002 amperes).

Now, let’s put together what we’ve discussed about power, voltage, and current.

First, the power in a circuit is limited to the power output of a power supply (the battery of cells in the case of a TASER device). We make a sophisticated device, but there is no perpetual motion machine.

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.

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

            P (power) = I (current) * V (voltage)

In the next section we 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.

For example, if the battery of cells in a TASER device could output a maximum of 50 watts, 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: The higher the voltage, the lower the output current must be!  And, again, current is the key measurement for how electricity affects the body.

·         Voltage determines how far an electric arc can jump.

·         Current determines how intensely the human body will react.

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 charge per second that is actually delivered.

RMS current is an approximation for the current used when analyzing continuous alternating currents (AC), as opposed to pulsed current (e.g. that 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, first square all the values, then average, 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 heat an electric current can generate, or how much light a light bulb can emit. Also, since the utility companies sell electricity based on power consumed (watt-hours), RMS current is proportional to power and is hence a good measure for electricians and the utility company.

The average current is more relevant to measuring TASER device outputs and far more relevant to stimulation, rather than heating (or continuous output), because it looks at the actual amount of 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 significantly overstates the current because the high peaks are squared before averaging).

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 small round hole. Because many of the electrical safety standards are based on alternating currents, and because those standards include mathematical adjustments for comparing pulsed currents, TASER measured the RMS current of the TASER for comparison to those electrical safety standards which used RMS currents.

TASER ECDs Basic Electrical Characteristics