Why does a stun gun (million volts) not kill a person, but 220V from a socket does?

Question

Physics

A person dies from the power of the current. There is a formula: I=U/R (voltage/resistance). The resistance of the human body is a certain constant, i.e. current is directly proportional to voltage. According to this logic, if 220V kills a person, then 1,000,000V should grind him to powder. Why is it not?
The option "there is a capacitor, it is quickly discharged and simply does not have time to kill" - looks implausible. In this case, such a blow should leave a charred trace. Lightning, like a discharge of a capacitor, has time to melt the chains around the neck, leaving a person alive.
The option "the internal resistance of the shocker is very large, so the current strength is small" - looks plausible, but creates even more questions. How, then, would a person feel a blow at all? Current (== current strength) is the number of electrons per second. With a low current strength, the number of electrons will be imperceptible. Voltage is a force that pushes electrons. Resistance is essentially the opposite force to voltage. Explain how having a force that is ready to push through a huge number of electrons, but is unable to due to high internal resistance, causes a person to feel a blow?

Answer 1

When dealing with physics (describing the behavior of moving charges) and physiology (describing the reaction of a living body to a moving charge), one cannot operate with "logic", which involves not specific values ​​of physical quantities, but "very much" "very little" and so on.
Let's start with what generally kills in the event of an electric shock. For death from electric current to occur, certain conditions must be met (at least one): cardiac arrest (caused by muscle contraction under the action of current flowing through it), irreversible damage to the nervous system, deep tissue burns.
To stop the heart (if we do not take the case of patients or those who have a pacemaker installed), it is necessary: ​​that the current through the body be somewhere above a quarter of an ampere (when the current is applied for more than a second - above 50-70 mA), so that it flows exactly through body and affected the heart, and did not pass through a small patch of skin. Therefore, for example, if you take the same notorious "220 from the socket" and attach two wires to the skin on the arm while the person is standing on a sufficiently thick insulator (to prevent current from flowing through the capacitance between the legs and the floor), the hand will burn, but no one won't die. And, conversely, under certain conditions, the same person can be killed by a current source with a voltage of a modest four dozen volts, by applying voltage between his left arm and legs, providing overhead contact (a large area of ​​​​contact with the wires, wet skin). High voltage certainly plays a significant role in the process, but this role is not the only one. Frequency also affects the strength of the impact: muscles react differently to direct current, low-frequency alternating current (tens of hertz, as in a power supply), higher frequency current (a few kilohertz). A higher frequency alternating current needs a longer duration of exposure, since the muscles react to it more slowly. Also, high-frequency currents due to the properties of conductivity are "displaced" to the surface of the body. Which, other things being equal (voltage, current, points of application to the body) make them less dangerous, since the amount of current through the internal organs decreases by orders of magnitude. Frequency also affects the strength of the impact: muscles react differently to direct current, low-frequency alternating current (tens of hertz, as in a power supply), higher frequency current (a few kilohertz). A higher frequency alternating current needs a longer duration of exposure, since the muscles react to it more slowly. Also, high-frequency currents due to the properties of conductivity are "displaced" to the surface of the body. Which, other things being equal (voltage, current, points of application to the body) make them less dangerous, since the amount of current through the internal organs decreases by orders of magnitude. Frequency also affects the strength of the impact: muscles react differently to direct current, low-frequency alternating current (tens of hertz, as in a power supply), higher frequency current (a few kilohertz). A higher frequency alternating current needs a longer duration of exposure, since the muscles react to it more slowly. Also, high-frequency currents due to the properties of conductivity are "displaced" to the surface of the body. Which, other things being equal (voltage, current, points of application to the body) make them less dangerous, since the amount of current through the internal organs decreases by orders of magnitude. A higher frequency alternating current needs a longer duration of exposure, since the muscles react to it more slowly. Also, high-frequency currents due to the properties of conductivity are "displaced" to the surface of the body. Which, other things being equal (voltage, current, points of application to the body) make them less dangerous, since the amount of current through the internal organs decreases by orders of magnitude. A higher frequency alternating current needs a longer duration of exposure, since the muscles react to it more slowly. Also, high-frequency currents due to the properties of conductivity are "displaced" to the surface of the body. Which, other things being equal (voltage, current, points of application to the body) make them less dangerous, since the amount of current through the internal organs decreases by orders of magnitude.
The same factors in different combinations affect the damage to the nervous system and burns. In stories with a lightning strike, the question always remains whether the current flowed through the body, or along its surface, or in general only "tangentially" (wet, not very clean clothes have less resistance, and the mechanism for the flow of currents of such a high voltage deserves a separate article) .
Speaking of "shockers", you can also look at specific numbers. For example, Taser declares the following electrical parameters for some of its models: pulsed current, each pulse with a total length of about 120 microseconds, pulse repetition rate - 20 times per second, current frequency inside the pulse - 10 kilohertz, current strength in the first pulse period - up to 3 Amperes , then decays very quickly. What can we learn from this? And the fact that the pulses are too short to cause lethal changes, the frequency is too high to create a high current density through the internal organs (obviously chosen to affect only the motor muscles on the surface of the body), the pulses follow quite rarely. Plus, the shocker electrodes are never attached to different ends of the body. Therefore, if you do not try to specifically intervene in the design,

Answer 2

What are you saying.
I was beaten by 220 volts 10 times. And nothing.
Large volts - affect how well electricity will penetrate protection (clothes, air). But nothing is said about the strength of the impact.
In addition to volts, there are also amperes .... An
ordinary household outlet easily and naturally gives out a little more than 10 amperes.
In addition, the current strength is determined not only by the resistance of the load (that is, a person in this case), but also by the sum of the load resistance and the internal resistance of the current source.
A socket has an extremely small internal resistance, but an electric shock has a much higher resistance than a person.
In addition to the current strength, its duration is also important, and the stun gun uses such a capacitor that the current in it ends almost instantly.
There is enough current coming from the outlet to turn you into coal if the RCD or automatic fuses do not work and burn out from overloading the wire.

Answer 3

the error
dies from the amount of energy that passes through the body - that is, from the power and duration of exposure.
the stun gun is the power of a small battery concentrated in the capacitor - it is short-term, it only manages to shock the electric shock
in the outlet for a long time
if several stun guns hit at the same time, then there will be death,
or vice versa, it can stop heart run

Answer 4

It's about the current loop. If 220 is passed not through the whole body but through a section of a limb, then that section will simply burn out, and if the limb is amputated in time without allowing the toxins of thermal decay to seep into the blood (blood poisoning), then the damage to health will be minimal and the person will lose only a limb or part of it.