A Taser fires two small barbed probes into a person’s body, then sends rapid electrical pulses between them that hijack the signals controlling skeletal muscles. The result is involuntary, full-body muscle contraction that temporarily prevents a person from moving, regardless of pain tolerance or determination. The entire process, from trigger pull to incapacitation, happens in a fraction of a second.
What Happens When the Trigger Is Pulled
Pulling the trigger ignites a small nitrogen gas cartridge inside the device, which launches two dart-like probes trailing thin insulated wires. These probes travel at roughly 180 feet per second and are designed to penetrate clothing and embed in the skin. The two probes need to land at different points on the body because the electrical current flows between them, passing through whatever muscle and nerve tissue lies in that path.
The spacing between the probes matters. A wider spread means the current travels through more muscle groups, producing more complete incapacitation. This is why officers are trained to aim so that one probe lands higher on the torso and the other lower, maximizing the distance between contact points.
How the Electrical Pulses Override Your Muscles
Your brain controls movement by sending electrical signals down motor nerves to your muscles. A Taser essentially drowns out those signals with its own. The device delivers short, repetitive electrical pulses, each lasting just 10 to 100 microseconds, fired 10 to 19 times per second. These pulses are strong enough to trigger involuntary muscle contractions but far too brief to cause permanent tissue damage.
The peak voltage is high, around 50,000 volts, but that number is misleading on its own. That voltage exists only to arc across clothing and air gaps so the current can reach the body. Once the circuit is established through tissue, the average current drops to about 1.9 milliamps. For comparison, a standard household outlet delivers thousands of times more current. The voltage gets the electricity where it needs to go; the carefully controlled current is what actually affects the muscles.
Research modeling the electrical fields inside tissue found that the current density and field strength in muscle layers exceed the threshold needed to activate motor nerves but remain well below levels that would cause permanent cellular damage. In practical terms, the device is powerful enough to lock up your muscles completely but not powerful enough to injure the tissue itself.
What Incapacitation Feels Like
When both probes connect, the person loses voluntary muscle control almost instantly. The electrical pulses cause muscles throughout the affected area to contract simultaneously and continuously. Because opposing muscle groups (like biceps and triceps) are all firing at once, the body essentially locks up and the person typically falls to the ground rigid or in an uncontrolled collapse.
A standard discharge cycle lasts five seconds and can be repeated. During those five seconds, the person cannot voluntarily override the contractions. Once the current stops, muscle control returns almost immediately. Most people describe the sensation as intensely painful and completely overwhelming, but the effect is temporary. There is no lingering paralysis after the current stops flowing.
Probe Mode vs. Drive Stun Mode
Tasers can operate in two distinct ways, and the difference between them is significant. In probe mode, the two probes create a circuit across a wide area of the body, and the electrical current passes through deep muscle tissue and motor nerves. This is what produces true neuromuscular incapacitation, the full-body lockup that makes a Taser effective regardless of how motivated or pain-resistant someone is. The effect relies on directly overriding the nervous system, not on causing pain.
In drive stun mode (sometimes called direct contact mode), the device is pressed directly against the body without launching probes. Because both contact points are right next to each other on the device’s face, the current only passes through a tiny, shallow area of tissue. This produces intense localized pain but does not cause muscular incapacitation. A person in drive stun mode can still move, fight, and run. It functions as pain compliance only, which is why law enforcement agencies consider probe mode the primary method of deployment.
Effects on the Heart
The most common safety concern is whether a Taser can disrupt heart rhythm. A study monitoring 84 Taser exposures across 28 volunteers found no cardiac rhythm disturbances of any kind. Heart rate increased by an average of about 11 beats per minute (from roughly 122 to 133 bpm), which is consistent with the stress and pain of the experience rather than a direct electrical effect on the heart. Key indicators of cardiac electrical function, including the intervals that reflect how the heart’s chambers contract and reset, showed no significant changes.
The device’s electrical pulses are specifically designed to affect skeletal muscle, which responds to different signal patterns than cardiac muscle. The extremely short pulse duration (microseconds rather than milliseconds) is long enough to trigger skeletal muscle contractions but too brief to reliably capture the heart’s electrical cycle. That said, most safety research has been conducted on healthy adults. People with pre-existing heart conditions, those under the influence of certain drugs, or individuals subjected to prolonged or repeated discharges may face higher risk, and deaths following Taser use, while rare, have been documented.
Why Voltage Alone Doesn’t Tell the Story
The “50,000 volts” figure gets attention, but voltage by itself doesn’t determine how dangerous an electrical exposure is. What matters is the combination of current (how much electricity flows), duration (how long it flows), and pathway (where it flows through the body). A static shock from a doorknob can exceed 25,000 volts but carries almost no current and lasts for nanoseconds, so it’s harmless.
A Taser’s design uses high voltage as a delivery mechanism to punch through barriers like thick clothing, then tightly regulates the current to a level that disrupts motor nerve signaling without reaching the threshold for tissue destruction. The pulses at their peak can briefly reach about 3 amps, but these spikes last only microseconds. Averaged over time, the current stays under 2 milliamps. This careful engineering is what makes the device capable of completely immobilizing a person for five seconds while leaving them physically unharmed once the cycle ends.