Electrical charges going through a chain of joined people.

Last Saturday night, I was drinking with my fellow gamers at the Texas Renaissance Festival. One of the guys had a new toy. Actually, a battery charged fly swatter that he got in Indonesia, for the equalivant of 3 bucks. I works just like a bug zapper. With 2 AA batteries.

We started by touching one side. Not much happened. touch both sides at the same time, I got a good jolt. The experimentation then started in earnest. First we had two people holding hands, then touching the fan at the same time. Then three. Then four. Up to six people holding hands, with each person at the end of the lines touching the swatter at the same time. We all got jolted. Some of those touching even felt their hands stick to the zapper. There were more present, but no more than six of us willing to increase our empirical knowledge.

The experiments got sillier. With hands on the forehead for “faiith healing,” and hands on the neck and back.

My question. How many people would it take in the chain to diminish the shock?

The consensus from those experimenting who have had some electrical experience feel that it would not matter how many people were connected. A couple of us theorized about 25 to 30. I would guess there would be some attrition of electricity at some point.

Well, its a simple series circuit. Assuming all people had the same resistance and the resistance of the zapper is negligible, twice the amount of people would lead to half the amount of jolt.

What would be more interesting would have been to try a paralell circuit. That is, have 2 people hold onto the ball at the same time. That would decrease the resistance and both people would feel a mightly jolt.

Sorry, I have nothing to add, just
wanted to say, Wooo you guys SURE
know how to have a good time!

I wonder if the amount of fluid in your bodies contributed to the conduction. You certainly can’t say it’s effect was entirely negligable.

The voltage should be around 1 KV at the least. No way of knowing how many people would be needed to make it safe.

If you want to make your own zapper, here is a simple way,

From any old (new is good too - if u care ) power adaptor, take out the transformer. You can get an adaptor at your goodwill store or someplace for a buck or two.

Connect the secondary coil of the transformer to a 1.5 volt battery. AA size is good enough. Connect the secondary to whatever you want zapped
Everytime you connect the primary to the battery or disconnect it - the secondary will send a schock. The bigger or more number of batteries, the greater the shock. AND the schok will come only when you connect or disconnect, not while you keep it connected or disconnected. The shock will be momentary.

This may be a good way to learn electromagnetism and flux linkage.

**The above is extremely dangerous and don’t do it unless you know what you are doing. In any case don’t blame me **

That is what we did, I believe. We had six people holding hands, in a circle, with the person on each end touching the swatter. Just one person touching the swatter, it did nothing.

http://members.ozemail.com.au/~macinnis/ockhams/ed_davy.htm

My bug zapper produces 1500V AC and 750V DC on the electrode grids. Use anywhere from 30K to 300K Ohms per person (varies depending on skin moisture & tightness of grip), apply ohm’s law and there you go. A few microamps is enough to get your muscles to twitch. In this case it’s more the pressure of the high voltage than it is the current that causes the muscle jerk reflex (think static shock).

Figure the opposite on the zapper resistance and it will be easy to figure out.

You should have pretty high voltage and a very high internal resistance. The reason that adding multiple people to the chain doesn’t significantly affect the amount of perceived shock is because adding the people doesn’t affect the total resistance much (on a percentage basis) and therefore doesn’t alter the current flow much. You would get that situation if the internal resistance of the zapper was many times the resistance of a person.

No, the situation you describe is a series circuit. A parallel circuit would have two “loops” of people, e.g.:

``````

o-o-o-o-o
|       |
*-o-o-o-o
|       |
o-o-o-o-o

``````

Where * is the zapper and o are the people

Hmm, just noticed that in this arrangement, one of your people needs to have three arms. If you’re standing at the ‘branch’ position, you’ll have to offer up some other appendage for the other folks to hold on to…

Ouch! :eek:

Um, please note that electric shocks where the current path is through your chest CAN KILL YOU. If a big pulse of current hits your heart at just the right time, it will trigger a heart attack (the timing is only correct in maybe one chance out of a few hundred random attempts.) Holding hands in a chain is a great way to create a lethal current path. Also, if one person in the chain has an undiscovered heart condition, the chain-shock can expose this problem… by stopping their heart. Great party trick.
Lethality aside, I figure that you’d need around 55 people to cut the shocking current by half, and you’d need an enormous number to eliminate the shock entirely.

I had the same “flyswatter” and measured the output at only 1200 volts DC. (I was hoping for more like 10KV).

If I’m typical, then the electrical resistance of human skin for small-area electrical contact is a few hundred ohms or a couple of thousand ohms at most. Touching the 1000V power supply against a couple 500-ohm fingertips gives you pulses of one ampere. That should be REALLY painful! Even 1/1000 ampere pulses makes your muscles twitch violently.

On the other hand, the average current produced by the flyswatter can’t be one ampere (one amp at 1000V is a kilowatt after all!) So, the current will depend on the internal limitations of the power supply inside the swatter. If the device is, say, 2 watts on battery power, then when connected to a 1000-ohm patch of human skin, the current through flesh will be 45/1000 amperes (45 milliamps, which should give a very painful shock with muscle spasms.)

How long a chain before you can’t feel the shock anymore? If you form a human chain, but if you all firmly hold hands, then the fairly large area of skin contact of hands will be different than when you touch the narrow flyswatter wires with a fingertip. Holding hands gives VERY good conductivity, so adding lots more people to the chain might not reduce the level of electric current going through your muscles. Why? It’s because most of the electrical resistance is from the fingertips touching the flyswatter wires, and this determines the current and also swamps out the effect of the added electrical resistance between vast numbers of sweaty palms in contact. If the fingertips contribute 500 ohms and the hand-holding surfaces each contribute ten times more conductivity or 50 ohms, then a one-person chain would feel 45 milliamps, but ten people in series would still get 37mA (still just as painful). To cut the current in half you’d need around FIFTY people. To bring it down below the threshold of feeling (of around 1/2 milliampere) you’d need, ahem, 160,000 victims.

Important note: we’re talking SIGNALS here, not energy. 50 milliamperes current in your flesh creates a nerve signal for major pain, even though the energy involved just slightly heats the skin in contact with the wires and doesn’t heat your muscles significantly. The skin presents most of the resistance and gets most of the heating. The people holding hands in the chain wouldn’t even feel the skin heat, but they’d suffer the same pain since their nerves “hear” the same 45mA signal which whispers to their muscles “experience agony now.”
PS Include some people with very dry palms and you’d need lots fewer in your chain.

How are you measuring this voltage ? I assume you are using somekind of voltmeter, which will give you a wrong reading due to the following:

1> Transients - The DC Voltage Generated in these devices is not flat. Rather like a high voltage peak which rapidly (exponentially) decays. Most Ordinary Voltmeters will measure the RMS value of this voltage, and there is not way of telling what was the Peak Value ( No this is not a sinusoidal AC where Peak value is sqrt(2) * RMS). To see the peak value, you will have to use a good oscilloscope.

2> Frequency Response - Ordinary Voltmeters have poor frequency response and the voltage read decreases with the frequency. This will give you a lower reading than actual.

3> Internal Impedance - The internal Impedence (Not Resistance) of the Voltmeter should be higher than that of the Bug Zapper (not likely). This is kinda related to #2.

Use a Oscilloscope to get better readings.

Realized.

I used a 100MOhm DVM for RMS values. My scope is burried under the bed. For this thread I felt ballpark measurements were good enough. Anyway, humans will load this particular source much more than the meter will.