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Stun Gun Ad Sells False Sizzle

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Rob Spiegel
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Sound waves rate the strength of the gun
Rob Spiegel   9/17/2013 9:51:53 AM
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I find it interesting that the sound of the stun gun's pop can reveal the strength of its stun power. That actually fits how the human brain rates danger. The louder the sound, the more our nervous system reacts.

tekochip
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Re: Sound waves rate the strength of the gun
tekochip   9/17/2013 1:00:15 PM
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The loudest SNAP I ever heard came about while I was cleaning out the sump pump during a thunderstorm, when I was young and foolish.  As I approached the pipe with a screwdriver I saw a large arc jump across the pipe and into my hand with a loud SNAP!  My arm flew across the room and the rest of my body chased after my arm, having grown quite found of it after all those years.  It wasn't until then that the thunder sounded.  The thunder was louder than the SNAP, but the SNAP had visual and sensory cues that the thunder lacked.
 
After that any problems with the pump were resolved after the rain stopped.


NadineJ
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Re: Sound waves rate the strength of the gun
NadineJ   9/17/2013 2:40:02 PM
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I've never seen an ad for stun guns. Based on the description, this is a great example of emotional targeting in advertising. 

Those who are attracted to this probably feel powerless.  Offering more "power", even if it's ineffective, hits the target.

Charles Murray
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Re: Sound waves rate the strength of the gun
Charles Murray   9/17/2013 6:37:40 PM
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Here's a link to 14 million volt stun gun. Luckily, it also has a built-in flashlight so you can get a better look at who you're zapping.

http://www.amazon.com/14-000-Stun-Gun-Flashlight/dp/B007Z3MWH4

AWItom
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Re: Sound waves rate the strength of the gun
AWItom   9/18/2013 10:15:52 AM
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Charles


Took a look at your 14 million volt stun gun.  Reading the description it says that the voltage is hard to measure, so they made the part number of the gun 14,000,000V!  How do you like that for clever marketing?  This was to show that their gun had a similiar voltage to other stun guns.  They have no description of what the actual voltage and current of the gun is.

Charles Murray
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Re: Sound waves rate the strength of the gun
Charles Murray   9/18/2013 6:08:43 PM
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Thanks for the info, AWltom. I'm amazed they did that. I quickly looked on Amazon for a stun gun, saw the 14,000,000 V part number and assumed they were claiming that it was 14 million Volts. It's clearly a marketing ploy, and I'm sure I'm not the only one who made that ssumption.

etmax
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Re: Sound waves rate the strength of the gun
etmax   9/26/2013 9:37:15 PM
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Ah yes, assume = ASS-U-ME :-)

 

kenish
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Re: Sound waves rate the strength of the gun
kenish   9/18/2013 1:37:10 PM
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14MV with a flashlight....isn't that called lightning?

Critic
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Re: Sound waves rate the strength of the gun
Critic   9/26/2013 3:56:43 PM
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Voltage sells! 

In this instance, 14,000,000 V is the model number, not the voltage.  Read the product description!

William K.
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Re: Sound waves rate the strength of the gun
William K.   9/28/2013 5:48:59 PM
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Critic, with a model number like that I am certain that the intention is to mislead the potential buyer, which is something frequently done these days. Intentionally giving a false impression while technically not telling a lie. It happens all the time.

Charles Murray
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Re: Sound waves rate the strength of the gun
Charles Murray   9/17/2013 6:40:49 PM
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I don't know what the voltage of a Taser is, but I saw one in action at the Consumer Electronics Show in Las Vegas a few years ago. An unfortunate Wall Street Journal reporter volunteered to be tazed, and it did not appear to be a comfortable experience.

Rob Spiegel
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Re: Sound waves rate the strength of the gun
Rob Spiegel   9/18/2013 11:26:27 AM
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I can't believe someone would volunteer to be tazed, Chuck. I woiuld imagine you didn't have your hand up.

Charles Murray
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Re: Sound waves rate the strength of the gun
Charles Murray   9/18/2013 6:03:36 PM
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I did not have my hand up, Rob. The reporter who volunteered also allowed it to be filmed by a crew, and I think he was sorry he did. The Wall Street Journal actually posted it on their web site for awhile, but then they pulled it down, which was a good move. By the way, I have a nephew who's an Oakland police officer, and I believe he had to be tazed as part of his training.

Rob Spiegel
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Re: Sound waves rate the strength of the gun
Rob Spiegel   9/18/2013 11:38:19 PM
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Chuck, I think that's a good idea that police officers have to be tazed before they start to taze others.

Charles Murray
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Re: Sound waves rate the strength of the gun
Charles Murray   9/20/2013 6:50:40 PM
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Yes, judging by some recent news videos I've seen, tasers can occasionally be used a little too cavalierly.

Rob Spiegel
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Re: Sound waves rate the strength of the gun
Rob Spiegel   9/22/2013 3:44:19 PM
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That's right, Chuck. I thought the effect of tasers was well represented in "The Hangover."

btlbcc
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Re: Sound waves rate the strength of the gun
btlbcc   9/26/2013 5:45:44 PM
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The difference (unless the design has changed) between the Taser and a typical "stun gun" is that the Taser shoots (Springs?  Compressed gas?  Powder?) the two electrodes (sharp needles with fine wires attached) into the victim from a distance, penetrating most clothing and presumably, skin, so that a better and lasting contact is made, while allowing the user to remain our of arm's reach from the victim.  I can't say for sure, but I would imagine that the Taser might use lower voltage/higher current than a stun gun.

While the stun gun may be useful in an encounter with an unarmed attacker, any weapon that extended the attacker's reach could lessen the usefulness of the stun gun.  A better choice might be pepper spray, although in a crowd situation you might have some collateral damage.  On the one hand, I wouldn't want to have to use pepper spray in a crowded subway car, while a stun gun might be just the thing to discourage the pickpocket or purse snatcher.  Conversely, out in the open, the pepper spray might be the weapon of choice.

And, of course, for more serious social encounters, there's always a handgun, if you have a license to carry and the necessary training.  And for most of us, we need to pick one of these and go with it; unlike soldiers, it's not practical for civilians (particularly urbanites) to go about one's business hung about with various weapons, each to be used as the situation requires.

Brooks Lyman

etmax
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Re: Sound waves rate the strength of the gun
etmax   9/26/2013 9:44:10 PM
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The problem with guns is the potential for fatal collateral damage. There's very few use cases where the police can use a gun safely. If they hit the wrong guy with a taser at least he will usually live to tell the tale (or sue if he meets an ambulance chaser). A stun gun probably has no collateral damage unless the cop is fool.

Noor Khalsa
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Re: Sound waves rate the strength of the gun
Noor Khalsa   9/26/2013 4:09:56 PM
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Does it actually cause fibrillation at the heart, like an AC signal, or clamping (DC)?

I would think that if it caused fibrillation, there would be a lot more deaths from these.

 

Re: disreguarding high voltage signs - There was a local tagger here  who breached a substation barrier and began to spray paint. The subsequent arc flash left him with burns over 60% of his body. But, being young, he clung to life for several more days.

etmax
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Re: Sound waves rate the strength of the gun
etmax   9/26/2013 9:48:38 PM
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Fibrillation usually sets in when the current is above 60mA but below 200mA and it has to cross the chest to trigger heart arythmia. Also the frequency would need to be 20-150Hz. A Taser places the electrodes a couple of inches apart (a stun gun too) as well as using pulsed DC < 5-10Hz this both limits the current through the heart and is to low in frequency to trigger arythmia

78RPM
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Interesting Analysis
78RPM   9/17/2013 12:51:56 PM
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That is an interesting analysis. Thanks.

JimT@Future-Product-Innovations
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“Oh Voltage, Schmoltage!"
JimT@Future-Product-Innovations   9/17/2013 4:35:01 PM
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I remember Doc giving that lesson in "Back to the Future" demonstrating "Voltage vs. Amperage" where his hair was standing on end.   So I guess that really means that when you see those bold WARNING HIGH VOLTAGE signs on Cellular towers and other fenced-off electrical sub-stations, you can really just say, "Oh Voltage, Schmoltage --  I ain't scared" !!

wareagle_eng
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Re: “Oh Voltage, Schmoltage!"
wareagle_eng   9/17/2013 8:27:24 PM
People are impressed by "big numbers" with no understanding of what they mean.

While I was in college, some smartass painted a sign in the colors of the local power company (complete with fake logo) with the message "Danger 10,000,000 ohms!" and placed it next to an equipment locker. Of course, we EEs just chuckled and went on our way, but other people were actually crossing the street to avoid the sign!

armorris
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Re: “Oh Voltage, Schmoltage!"
armorris   9/18/2013 2:53:17 PM
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1 saves
High voltage is definitely dangerous when there is high current available. Ohms Law says that voltage is required to get current to flow through a resistance. You should never disregard a "High Voltage" sign.

A Van De Graaff generator produces a lot of voltage, but with very little available current. A stun gun also produces relatively small current. It can cause paralysis or pain, but produces no harm unless it passes through the heart, causing fibrillation. 

Charles Murray
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Re: “Oh Voltage, Schmoltage!"
Charles Murray   9/18/2013 6:14:44 PM
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Good point, armorris. Medical cardioversion typically uses fairly high voltage, with extremely low currents (in the mA range). On the surface, the low currents would appear to be benign, but coupled with a high voltage (100 V to 700V, as I understand), it's enough to stop a person's heart and allow it to re-set. So while it's true it doesn't kill the patient, it does stop the heart momentarily. Maybe a reader who designs these devices can weigh in with more (and better) information.

etmax
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Re: “Oh Voltage, Schmoltage!"
etmax   9/26/2013 10:18:56 PM
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Hi Charles, remember that the kiskstarter you describe uses 2 paddles that are placed on either side of the heart and use DC which clamps all muscles allowing a normal restart. A stun gun or taser places 2 electrodes 1-2 inches apart such that the current flows between them and the tissue engaged. Little or no current passes through the heart and it is pulsed DC (less than 10Hz) The current needed to cause vetricular fibrilation is > 60mA but < 200mA and the frequency needs to be between 20Hz and 150Hz. AND it has to pass through the heart, not 2 inches of skin. If you have a pacemaker or defibrilator installed the metrics change dramatically, and your emotional response to shock/stress can in sensitive individuals cause issues that may lead to death but that is reasonably rare. I would just hope that police know how to restart a heart. On the subject of high voltage and higher currents the issue is burning of subcutaneous tissue which can cause deadly levels of toxins in the blood and require amputation or other surgery, but neither stun guns or tasers get anywhere near that as you well know

Charles Murray
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Re: “Oh Voltage, Schmoltage!"
Charles Murray   9/27/2013 5:59:05 PM
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Great explanation, etmax. I didn't know that. Thanks much for the information. It could come in handy as we do future articles about defibrillators (which we have done on several occasions in the past).

btlbcc
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Re: “Oh Voltage, Schmoltage!"
btlbcc   9/26/2013 5:49:20 PM
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Actually, I believe it's required to put "Danger! High Voltage" signs on any piece of industrial equipment using 240VAC (and possibly even 120VAC), and I suspect that such voltages are present in a cell phone base station transmitter.

Brooks Lyman

etmax
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Re: “Oh Voltage, Schmoltage!"
etmax   9/26/2013 10:24:08 PM
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Interestingly, 120VAC is actually more dangerous generally than 240VAC because for vetricular fibrillation to set in the current has to be > than 60mA but less than 200mA. I've often received electric shocks from 240V and usually get local burns because the current is so high. This is a saving grace because it clamps the heart rather than rattling its rhythm.

armorris
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Exaggerated output voltage
armorris   9/18/2013 10:39:47 AM
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I read the description of the 14,000,000 volt stun gun also. I'm surprised that an American manufacturer did this. It just goes to show that to compete with the Chinese liars, you have to tell a bigger lie.

The written description indeed says that 14,000,000 is the model number, but the product details says that the model number is SGTTerminator 6.

In my opinion, the 14,000,000 is clearly an attempt to deceive the buyer, just as the Chinese routinely do. It would indeed require specialized equipment to measure the peak voltage of the stun gun, but it can be easily approximated by measuring the distance between the probes. The laws of physics limit the maximum output voltage.

The same manufacturer sells another one, quoting 12,000,000 volts and and says nothing about it being the model number. In the product details, the model number is given as SGT7800. The product details for this one does not say that the device is made in the US. It does say that "Terminator" is a US brand name, however. Still, a US company should know better than to make such a claim.

The retailers just pass on the information provided by the manufacturers.

bob from maine
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Re: Exaggerated output voltage
bob from maine   9/18/2013 11:12:51 AM
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I think the advertised voltage of a stun-gun is describing the maximum open circuit voltage that the electronics should be able to achieve. The actual operating voltage will depend on what the probes are contacting (bare skin, wool sweater, nothing). I think when selling to the average consumer, specsmanship is how to pique the buyers interest. Other than law-enforcement, I can't think of anyone who would use a stun-gun often enought to rate it's performance objectively. If it says 2 million volts and you buy and use it on someone, I doubt you'll care overmuch about the physics.

Tom-R
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Re: Exaggerated output voltage
Tom-R   9/18/2013 1:38:33 PM
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Reminds me of the toy company that named their stacking brick toys 0937. In the right font it spelled LEGO, upside down. What a coincidence...

William K.
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Stun Gun and other devices?
William K.   9/22/2013 6:31:08 PM
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At one time I heard a radio ad for a system called "Black Max", which was supposed to be ablke to shock attempting car-jackers.That was probably ten years ago.  I thought that was a very good idea, but I have not been able to locate the product. But the question is about how to complete the circuit, since just one terminal can't deliver much of a shock, at least not under normal conditions. And it would not bother me at all to put an attacker who had a gun at some risk, since getting shot is usually quite a bad thing. But 50,000 volts at even just ten milliamps is 500 watts, which is a lot of power to come from any package. But it would probably deliver enough zap to send the bad guys off in search of someebody less well protected. 

But that protection system seems to have just gone away.

samsuffy
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Re: Stun Gun and other devices?
samsuffy   9/26/2013 4:14:29 PM
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To William Kay

When I was a teenager, we would create a shock circuit for cars by using an ignition spark coil powered from the battery through a buzzer salvaged from a doorbell or old car radio. Mount the coil on some convenient place under the car and allow the hot wire from the top dangle to the ground. Anyone toching the car while standing on the ground would get a considerable shock. You could even nose the car up to another one and chart it also. Be sure to include a cutoff switch. We had a lot of fun.

Sam Suffy

jhankwitz
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Re: Stun Gun and other devices?
jhankwitz   9/26/2013 5:43:38 PM
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I remember that well. We had that system hooked up to my old man's 1951 Cadillac. We used an isolated/insolated chain dangling on the ground. While driving, wind force would keep it from dragging and wearing out, but when stopped, it would lay on the ground. We had to make sure the ignition was 'off' when exiting or entering the car. ZAP!

btlbcc
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Re: Stun Gun and other devices?
btlbcc   9/26/2013 5:52:18 PM
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I suspect it went away for legal liability reasons.  It's a sort of booby-trap after all, and the law frowns on such.  A little old lady leans on your car, gets zapped and has a heart attack or falls down and knocks her head on the sidewalk...  Not good.

Brooks Lyman

William K.
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Re: Stun Gun and other devices?
William K.   9/28/2013 7:35:47 PM
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The Black Max system as I would implement it would be controlled by a normally off momentary switch. So it would never be active unless it was intended to be active, even safer than a gun because it would not be able to go foo accidentally. It would only be activated when I saw a person with a gun approaching, or attempting to pull the door open. So the little old lady would be perfectly safe unless she pulled a gun. It is intended to be an active response to a specific threat, not a burglar alarm sort of function. Big difference there. Besides that, the system would be installed in a manner such that it could be removed and disposed of in a hurry, being replaced by an electronic siren of similar dimensions.

bob from maine
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Re: Stun Gun and other devices?
bob from maine   10/1/2013 4:16:21 PM
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The Black Max is/was a good idea; except - when the bad-guy tried to open the drivers door and got zapped his immediate response was to jump backwards - into traffic. A satisfying end to a potential car-jacker, though tragic to granny who approached the wrong car. I think they have been outlawed. I built a zapper to disuade squirrels from using our bird feeder using a flyback transformer from a TV, a capacitor, resistor, relay and a push button. It never killed a squirrel - quite - but it took them several minutes to recover. Output was in the 12-18KV range and produced just one pulse. Squirrels can fly! But they learn quickly. I think electric fences are 70V open circuit and limited to 60mA. Considering how unpleasant an electric fence is, I can't imagine how painful a Taser must be.

etmax
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Re: Stun Gun and other devices?
etmax   9/26/2013 10:37:08 PM
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Hi Will, your calculations are sound but typically a 50,000V generator in a Blackmax type device while being able to deliver 10mA will only be able to supply 5W which means that the voltage will collapse to around 500V.

Of course 500V is plenty to push that 10mA through your skin and 10mA will feel decidecly uncomfortable

The 50kV is so that it will strilke an arc that will penetrate most clothing and while the voltage drop across the clothing may be as high as an additional 500V that still means 5mA which is a deterrent.

Re why only 5W?


Well from a car battery 500W means >40A@12V to produce it and also higher power cause death and liability :-)

On the side, if you removed the skin from a person's right and left hands (skin resistance is high) and attached their hands directly to the terminals of a 12V battery. you would most likely get enough DC current through the heart to defibrillate it. :-) it's all ohms laww

William K.
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Re: Stun Gun and other devices?
William K.   9/28/2013 5:53:43 PM
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The only purpose of a "black Max" type device is to discourage a carjacker. And as long as the discomfort is enough to stop them withing a very few seconds that is the only requirement. 40 amps from an automotive battery for even a whole minute would not be a big deal, which is why the power is not higher. 

Besides, throwing a solid arc to a bad-guy's hand is a great psychological deterrent, don't you think?

etmax
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Re: Stun Gun and other devices?
etmax   9/28/2013 10:52:53 PM
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Absolutely :-) BTW I was sitting on my chair writing my previous post with my ear plugs in and as I rolled the chair back a little I could hear eletrical noise in the ear plugs and there was an electrifying sensation as sparks flew from me (my ear canal :-( )) to the metal parts of the ear plugs which got stronger as the chair moved more. That was a deterrent too, I didn't move my chair the rest of the night! We've had a very dry gusty northerly the last few days and the humidity is down below 40%.

KingDWS
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Re: Stun Gun and other devices?
KingDWS   2/12/2014 4:05:39 PM
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Perhaps the reason its not available is that it only takes 5-7ma not 10 to kill someone. It's not enough to stop the heart which can happen over 10ma but what it does for a fair amount of certain people is cause multiple fibrilations that sort of override the natural beat. So instead of stopping it and the person dies the heart looses its ability to pump as all the chambers get out of sync. Same dead result just 30-50% lower ma levels. The volts can go up much higher but then you get skin charing and internal scar tissue if your really concerned that much about your potential attacker. ;-]

etmax
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Re: Stun Gun and other devices?
etmax   2/12/2014 10:39:32 PM
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We did a session on the effects of electrical current on the human body at engineering school and what we were told was that:


1. DC doesn't cause ventricular fibrilation.

2. Frequencies below ~20Hz and above about 200Hz don't cause ventricular fibrilation.

3. The AC current required to cause vetricular fibrilation is around 60mA to 200mA.
 Below 60mA that it isn't sufficient to overide the heart's own timing and above 200mA the heart is clamped similar to DC because of overload. There may be burns but no fibrilation.

Obviously someone with a heart pacemaker will have a different set of risky conditions and tests have shown that inductive cook tops can be risky for them.

BTW, items 2 and 3 are why the telecom ring signal was 17Hz at 100V peak back in the day.

a.saji
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Re: Stun Gun and other devices?
a.saji   2/13/2014 4:33:57 AM
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@kingDWS: That is interesting. It shows that there are some interesting facts about health and effects on electronics towards it. Wondering what sort of an effect it has on rays in my working area on a daily basis. 

Technophile
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Transient or steady-state?
Technophile   9/26/2013 4:07:34 PM
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While I agree that the voltage claims seem highly exaggerated for sales purposes, I will be a bit of a devil's advocate about the maximum voltage across a spark gap.  Let's state some assumptions:  in atmosphere, clean air, within 1000' of sea-level, 25%..75% RH.  Are you also assuming steady-state conditions or transient?  I would expect ionization of the air across the gap to take some amount of time. 

Critic
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Nice Post, Thanks!
Critic   9/26/2013 4:37:27 PM
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The truth is that you don't need a lot of voltage to shock or kill someone. 

While the calculation in the article is approximately correct for the voltage required to initially break down the spark gap, once the arc starts, the voltage is significantly lower than the inception voltage.  If the stun gun terminals were in contact with human flesh, the voltage would be even lower.

The resistance of a human, over a short distance, if the skin isn't broken, is on the order of a few thousand ohms, up to maybe 100 k ohms.  As little as 10 mA can cause a painful shock, so the required voltage could be as low as (assuming R = 5k ohms) 50 V.  To be sure to shock a high-resistance person, you need about 1 kV. 

So a stun gun needs to produce at least 200 kV (in round numbers) to break down the spark gap, with enough current at a lower voltage to make a hot, noisy arc, and it needs to be able to source at least 10 mA at voltages in the range of 50 V – 1 kV.  I am sure the people who make stun guns have this all figured out, and they have also figured out that the words "high voltage" or high numbers are what scare people.

Your body will only be at 100 kV potential (relative to one the Van de Graaff generator's terminals), when you touch the Van de Graaff generator, if you are not directly across its terminals.  That is, the output current of the Van de Graaff generator flows though your body, but the voltage drop across your body is small compared to the voltage drop though the air between you and the other generator terminal.  Picture yourself being a small resistor in a large divider.  You can safely touch one terminal of a 100-kV source that is capable of high current, as long as you are insulated from the other terminal.

Mohamed Shaltot
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Do not judge voltage by electrode distance
Mohamed Shaltot   9/27/2013 1:27:58 PM
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Isn't it possible the stun gun is generating very high voltages (through capacitive discharge) but the distance seperating the elctrodes is simply governed by practical limitations (size of device, handling, ...etc) as opposed to the max voltage generated/dielectric breakdown of air (20-30K per inch)?  In other words, I could generate 1MV (just an example, not feasible in such a small pachage without serious insulation), but choose to seperate the electrodes 1 inch only.

William K.
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Fence chargers and "liitle old ladies"
William K.   10/1/2013 8:12:10 PM
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Electric fences deliver a whole lot more than 70 volts. On the more standard units that I have worked on the primary voltage is about 100 volts, and the secondary of the step-up transformer has a turns ratio of about 1:50, or possibly much more. The spark from a properly functioning fence charger will easily jump a quarter inch, indicating about 2500 volts. The "high powered" fence chargers, designed to electrify a mile of fence around a horse pasture, use a capacitor charged to about 700 volts to pulse the primary of a much larger transformer. The output of that device will jump over a half of an inch with a loud snap.

As for the possibility of injuring an innocent person, that is unlikely since the system is only turned on when I would press and hold the button. Releasing the button switches the system off immediately. So unless some old lady points a gun in my direction and grabs the door handle there is no way they could get a shock. But, of course, the "Black Max" was taken off the market because somebody felt that it dould be dangerous. They refused to consider that a carjacker with a gun is dangerous. Bottom line: YOU CAN'T FIX STUPID. (note that I did not invent that phrase, but it certainly fits.)

etmax
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Re: Fence chargers and "liitle old ladies"
etmax   2/12/2014 10:50:26 PM
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They refused to consider that a carjacker with a gun is dangerous.

Yes that's the problem with the world, a person breaks into your house and trips on a roller skate and he can sue you. They need to change the law considerably.

Electric fences certainly pack a wallap and I've experienced them first hand. The risk profile to people is low because the pulse repitition rate is quite low you may well know exact figures but I believe it's in the order of 2-5 seconds.

I don't think a car jacker would let it deter them, or they might take a tyre iron to the car if they don't figure out how to bypass it.

William K.
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Re: Fence chargers and "liitle old ladies"
William K.   2/13/2014 9:53:22 AM
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If I shock a carjacker so that they stop threatening me with their gun I certainly will not stay around long enough for them to do anything else. And if it knocks them out, so much the better. Perhaps you don't understand that pointing a gun at somebody indicates that they are willing to shoot them. So at that point all the rules for polite discussion are suspended. The bad guy with the gun does not deserve my courtesy.

Gaffer Gaggs
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Circuit current kills
Gaffer Gaggs   1/9/2014 4:33:00 PM
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There was a receint article in one of the electrical trade magazines that explained the "kill voltage" for electrical systems was based on 13-15 WATTS through the body. The well researched article was based on some work in the 50's that RCDs and GFCIs standards are based upon that to kill a "normal" person that 13-15 watts of power had to go through a person's heart disrupting the normal sineous rythem. The article went on to explain the various resistances and impeadances areas; and pathways of the human body. They explained why (in this Country USA) GFCIs are required in "wet" areas such as kitchens, bath & laundry rooms, pool, ponds,docks and fountain areas where electricity is being used.

The US/UL reasoning of 6mA at 120VAC will prevent anyone (from a baby crawling across a floor to a 90 year old oriental woman blow drying her hair in the shower) from having a life ending shock ie. electrocution. The EU/IEC- RCD reasoning of a higher "trip" current of 20mA at 220VAC will prevent most people (98+%) from electrocution while allowing for fewer false trips of the personel portective devices. There were more lawyers in the US's litiguoes society than in the EU and the difference between the way the neutral/ground bonds are done in the various power systems. The baby and the 90 year olds were picked because they are the worst case senerios for electrical schocks.

If you want the full skinny, read "The Effects of Electrical Current Through the Human Body" its 800+ pages of research from worrld wide studies that set the standards; oh yeah it'll make your skin crawl when you read about some of the "test methods".  

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