What is the energy stored in a taser? Can you se 0.5*C*V^2?

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Discussion Overview

The discussion centers on the energy stored in a taser, specifically whether it can be calculated using the formula 0.5*C*V^2. Participants explore the workings of a taser, the role of capacitors and batteries, and the implications of discharging a taser into a conductive object.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that the energy released by a taser can be calculated using 0.5*C*V^2, assuming it contains capacitors.
  • Another participant clarifies that energy is stored in batteries that charge capacitors, and questions the sustained current output of a taser.
  • A participant mentions that tasers use high voltage pump circuits and may not rely heavily on capacitors for energy storage.
  • One participant calculates the energy output based on a voltage of 80,000 V and a battery capacity, arriving at a potentially high energy value, but acknowledges it may be a pulse rather than continuous current.
  • Concerns are raised about the calculated current of 100 C being excessively high, with some participants doubting the output current is more than a few mA at high voltage.
  • Another participant references the TASER website, stating a voltage of 5 kV, challenging the previously mentioned 80,000 V.
  • A participant discusses the effects of shorting a taser, suggesting that it would not cause painful heating but rather interfere with nerve signals.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the energy storage mechanism of tasers, the voltage levels, and the implications of discharging a taser into conductive materials. The discussion remains unresolved with no consensus on the energy calculations or the operational characteristics of tasers.

Contextual Notes

Participants reference various voltage levels and energy calculations that depend on assumptions about the taser's design and operation. There are unresolved questions about the current output and the implications of discharging a taser into conductive objects.

tsuwal
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How does a taser work? If it is a bunch os condensers that discharche, the energy would released would be 0.5*C*V^2. I'm asking this because I say in a movie a taser being discharged metal necklace. The necklace would have short-circuited and warmed a lot, right? Probably making a severe burn or something. What do you think?
 
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By condenser, do you mean a capacitor?
And I believe the energy is stored in batteries which charge capacitors in the taser.
As for the metal necklace heating up, I don't think a taser can supply much sustained current, as I believe most are designed to "pulse" in a certain way that interferes with the brains ability to communicate with muscles, thus incapacitating the victim while they are being tased.
 
tsuwal said:
How does a taser work? If it is a bunch os condensers that discharche, the energy would released would be 0.5*C*V^2. I'm asking this because I say in a movie a taser being discharged metal necklace. The necklace would have short-circuited and warmed a lot, right? Probably making a severe burn or something. What do you think?

If you use Google Images to search for Taser Gun Circuit, you can see what the basic circuits are. They are high voltage pump circuits, and don't rely much on storing energy on capacitors.

I don't know what happens when you short the output of a Taser, but probably not much. It would likely go into current limit, and not deliver much power. Don't believe everything you see in the movies! :smile:


EDIT -- Beat out by the space fighter jockey!
 
**Errata: yes, i meant capacitors.

I've seen that it uses a voltage of 80.000 V and is supplied by a battery of 9 V. The battery can be used 50 times, so assuming the battery has a capacity of 2000 mAh, iy supplies about 100 C each time. 100 C * 80 000 V = 8 MJ ?! This value is very high, but even assuming that it is a pulse and not DC, say, 1000 less, its still 8 kJ!
 
How are you arriving at the 100 C? That's a LOT of current. The equivalent of 100 amps over 1 second, a number which seems absurdly high.
 
Drakkith said:
How are you arriving at the 100 C? That's a LOT of current. The equivalent of 100 amps over 1 second, a number which seems absurdly high.

Agreed. I doubt if the output current is more than a few mA at [STRIKE]80kV[/STRIKE] 5kV. Don't want to kill the person, after all.
 
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tsuwal said:
**Errata: yes, i meant capacitors.

I've seen that it uses a voltage of 80.000 V

Where did you read this. I checked the TASER website, and they say it is 5kV...

http://www.taser.com/research-and-safety/how-a-taser-works

.
 
Last edited by a moderator:
You are correct when you say that covering yourself with tin foil will protect you from a taser by creating a short. The charge will then be transferred through the operator but not in manner that would harm the operator.

[STRIKE]When shorted, [/STRIKE]there isn't enough energy to cause painful heating. The pain is caused by electric interference with the nerves.
 
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