Enough to drop a grown man to the ground from just little batteries how?
In: Engineering
I think of it in terms of a little squirt gun. A small squirt gun could shoot a very thin jet of water with an impressive amount of force. The volume of water is low but the pressure is high. Compare this to say a fire hose slowly pouring out water. The volume is huge but it doesn’t have a lot of force behind it, and might not squirt nearly as far even though there’s way more water flowing.
The power remains the same. P=VI, V, or voltage, is extremely high to cause the startling effect, while, I, the current is extremely low so as to not be lethal.
AA batteries have a nominal voltage of 1.5V. Capacities vary, but a typical new AA might be rated for 2,000 mAh (milliamp hours). The total energy in the battery is 1.5V * 2000 mAh = 10,800 joules.
As a point of reference, that’s enough energy to lift 10,000 apples up by 1 meter. (source: https://en.m.wikipedia.org/wiki/Joule) That’s plenty of energy to do quite a lot of things!
Power is energy per second. The taser may be using less power than you might imagine. It sends an electric signal for around 2 milliseconds out of every second (0.2%). The power during those 2 milliseconds is fairly high, but it’s so brief that it doesn’t use as much energy as it might seem. Some clever electronics draws the energy from the battery relatively slowly, and releases it in those spikes.
Plenty of people talking about voltage vs amperage, but they’re missing one great factor: time. You can die from relatively low voltage if you get it for a longer period of time, but tasers just can’t do that.
To get a high voltage from tiny batteries, you have to charge condensators and it takes quite some time. That’s why small batteries are possible, you just need time beforehand to draw power out of them to get it ready for a larger burst that doesn’t last very long.
Tazers have transformers which step up the voltage from a handful of volts to tens of thousands.
Why isn’t it lethal? Because like the big jump in voltage (electrical force), there is a just as big drop in current (electrical flow) and current is what kills. There is enough flow to mess with voluntary muscle control but not enough to stop a heart. Even though it can’t stop your heart, it could cause a disturbance in the rhythm and trigger a problem though so don’t test it out. Tazers are considered “less lethal”, not “non-lethal”.
Power = voltage x current. Teasers are VERY high voltage and VERY low current. So the total power isnt very high. 4 AA batteries can supply that power
It doesn’t take a particularly large amount of electricity to disable a human. Our nervous system runs on very very weak electrical impulses so if you can deliver enough electrical current to stimulate our nerves, which are almost microscopic, we lose control of whatever muscle group those nerves control.
To put this in perspective, when someone’s heart is beating too slow, paramedics can use an external pacemaker. Basically they attach the defibrillator pads, and the defibrillator acts as a pacemaker delivering tiny shocks about 70 times a minute. Then, while watching the monitor, you gradually increase the amps until you see a “capture” on the monitor, meaning the shock is powerful enough to stimulate your heart to beat. It’s usually about 100 milliamperes. Like I said, our nervous system is very sensitive. It doesn’t take a lot of energy to disrupt it.
The human body doesn’t exactly respond too well when you try to pump electrical current through it. The threshold for how much current needed to kill a human is very low. So, it’s not that you need a large amount of power to immobilize a human. It’s that the current output is low enough so that it’s not deadly.
Capacitors and step up circuit boosting the voltage to the kV range while have almost no Amperage.
Voltage hurts but Amperage kills you
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