Voltage vs, Current

[Buck Parrish]

How can you have 50,000 volts on a taser gun, But, no current?

 

[charlie]

How can you have 50,000 volts on a taser gun, But, no current?

An open circuit. However, if you are in the circuit, some minimal current will flow and you will feel like you were just kicked by a mule.

 

[S'mise]

Their is current. Just not very much. Drag your sock feet on the carpeting for a few minutes and then touch someone. That spark of static electricity probably has about 20kv behind it, but not enugh current to electricute someone.

 

[Buck Parrish]

Are y'all saying that because the energy can not get back to the source that made it. Does that make it an open circuit?
Because I will stand on a fiber glass ladder and hold 277 v and not get shocked.
So does some how this laser gun let some energy back to the source. That way you feel like you are getting kicked by a mule. I am perplexd.

 

[S'mise]

Not exactly sure how Tasers work, but my guess is when you pull the trigger it fires a pulsating DC into a coil (similar to in your car) the secondary which is stepped up to the 50kv or so wich is conected to the darts that have a tiny wire attached to them. They stoot out of the gun and land in the back of the poor sap about 20ft away that now completes the circuit. Wa-La your confrontational subject quickly complies to your wishes as he becomes a human spark-plug.

OR,

The cops find out he had a heart condition after the fact and the city get sued for 10million for the death.

 

[Buck Parrish]

So it's the pulsating that makes the difference. Like on an electric fence.

 

[S'mise]

Yep, You get the idea, Just like an ignition system.

 

[76nemo]

Actually buck, those circuits aren't all that complex. I have schematics for them if you are all that interested. It's amazing what you can do with a 9volt battery:grin:

On the contrary, you ask about E vs I. I had a friend who's Father died from coming in contact with a CRT that had been discharged and sitting on a shelf for over 6 months. Contemplate that one. Discharged and idle for over 6 months, and it killed him almost instantly. Memorable capacitance.

Remember the guy who got hit at the coal mine with a Thumper?

 

[Besoeker]

So does some how this laser gun let some energy back to the source. That way you feel like you are getting kicked by a mule. I am perplexd.

There are two electrodes.

 

[iwire]

How can you have 50,000 volts on a taser gun, But, no current?

I am sure you meant 'low' current?

The short answer is the power supply for the circuit is simply not capable of providing much current. The power supply is purposely designed to make high voltage with low current.

 

[zog]

I am sure you meant 'low' current?

The short answer is the power supply for the circuit is simply not capable of providing much current. The power supply is purposely designed to make high voltage with low current.

Nailed it right on the head. Another case of where I does not equal E/R.

 

[S'mise]

What would I equal then Zog? :-?

 

[electricalperson]

what is the resistance of the average human body?

 

[S'mise]

Roughly 10k ohms on the surface but when the darts penetrate into your skin it's probably less than 200 ohms.

 

[iwire]

IMO other then the pain inflicted to the victim the resistance of the body is of little consequence.

The power supply can not supply high current even with it's leads shorted.

 

[zog]

What would I equal then Zog? :-?

Whatever the power supply is capable of putting out. There are limitations on Ohms law.

 

[zog]

Roughly 10k ohms on the surface but when the darts penetrate into your skin it's probably less than 200 ohms.

Closer to 20k for most people. internally about 200 ohms per limb, it all depends on what the path is.

 

[S'mise]

I was looking for a formula. I realize these values are probably immesurable but theoretically wouldnt ohms law still apply?

 

[charlie]

Whatever the power supply is capable of putting out. There are limitations on Ohms law.

There are never limitations on ohms law. However, there are limitations on the power supply as you have eluded to in your statement. Whenever you short the leads together, there will be a fault current flow. In the case of a person being the shorting bar and the 9 volt battery being the supply, this is really very interesting. Let's say the output voltage is pulsating DC at 50 kV and the human resistance is 400Ω, do you really think the voltage will be maintained and that there is anything less than a fault? If the voltage could be maintained, the current would be about 125 amperes through the human at 50 kV - not good.

The bottom line is that the voltage would start out at 50 kV and immediately drop to nearly zero volts until the next pulse. This is a very small mA flow and is very uncomfortable for the tased person. :smile:

 

[zog]

Right, what I mean is that the current cannot be found by dividing the voltage (50kV) by the body resistance in this case, not that Ohms law dosent work, it is rather the "law" cant really be applied due to the limitations of the power supply.