What happens if I apply a voltage to human flesh?

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Summary:

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if i apply a voltage to human flesh, human flesh would be at the full voltage? because i performed an experiment. i connect one end of a wire to the
the palm of my hand. i connect the other end to a battery. i connect the first battery to a second battery. i connect the second battery to a multimeter. i connect the multimeter to a wire. i connect the wire to the top of my hand. the voltage started at .98 volts and then very slowly rose. i stopped the experiment at 2.07 volts. So if i apply a voltage to human flesh, the human flesh would be at part of the voltage, not the full voltage?
 

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  • #2
anorlunda
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First, always mention safety. If those are 1.5V AAA batteries, the experiment is safe. With larger voltages it becomes unsafe. It always makes me squirm to hear about the human body used in electrical experiments. But since the voltages are so low in this case, I'll allow it.

Your description is incomplete. You have an electrical circuit that includes the leads to the multimeter, and the batteries themselves. Voltage is always measured as the difference between two points. In that circuit, there are many choices of the two points, and every one of them could give a different result.

So the premise to your question that the whole body is at one voltage is false.
 
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  • #3
DaveC426913
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If those are 1.5V batteries, the experiment is safe.
1.5 volts, 5 amps. :oldbiggrin:



I think he'll find that it is not trivial to get reliable electrical readings off leads connected to his palm and back of hand. Skin is a very fickle conductor. I'm surprised he got as good readings as he did. I would not take the variations in voltage as much more than problems with poor connectivity.
 
  • #4
anorlunda
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1.5 volts, 5 amps.
Good point. I edited it to say 1.5 V AAA batteries. Am I correct in saying that those things are pretty safe?
 
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  • #5
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i used 18650 lithium ion cells. the total voltage was 7.18 volts when not connected to my body. i got a reading of
first 0.98 volts. then the voltage very slowly rose. i stop the experiment when the voltage reached 2.07 volts. i started with relatively small voltage to be safe. i was trying to be safe.
 
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Your description is incomplete. You have an electrical circuit that includes the leads to the multimeter, and the batteries themselves. Voltage is always measured as the difference between two points. In that circuit, there are many choices of the two points, and every one of them could give a different result.
what are other choices of the two points?
 
  • #7
berkeman
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the total voltage was 7.18 volts when not connected to my body.
Please be VERY careful experimenting with this. I once got myself into serious trouble experimenting with a 9V battery during some contract development of a portable EKG machine, so even though the voltage seems low, if you make good contact with the skin you can conduct enough current into/through the body to do some damage.

Please have a look at these links to learn more about conductor-to-skin contact. There is a lot of chemistry going on at the interface, depending on things like how moist the skin is, how thick the epidermis is, whether the voltage is DC or AC (and what frequency if it is AC), etc.

https://alanmacy.com/books/the-handbook-of-human-physiological-recording/chapter-4-electrodes/
https://blog.biopac.com/choosing-the-right-electrode-type/
 
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  • #8
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So if i apply a voltage to human flesh, the human flesh would be at part of the voltage, not the full voltage?
I suggest you a safer and more direct experiment what might help you understand what happens: just switch your multimeter to resistance measurement and grab its probes with one hand. Check the measured resistance - the whole range of it.
That resistance (range) what was present in your first experiment: it gave a voltage divider together with the internal resistance of the multimeter (in voltage measurement mode).
 
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  • #9
DaveC426913
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i used 18650 lithium ion cells. the total voltage was 7.18 volts
I'm not an electrical whiz.
That battery is rated at 2850mAh.
Is that tantamount to saying it can deliver 2.85 amps?
And, at 7 volts, is that enough to be dangerous?
 
  • #10
berkeman
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And, at 7 volts, is that enough to be dangerous?
Only if you hook it up like I did... o0)
 
  • #11
berkeman
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That battery is rated at 2850mAh.
Is that tantamount to saying it can deliver 2.85 amps?
Only for an hour. After that it gets tired.

And never anthropormiphise a battery. They hate it when you do that. :wink:
 
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  • #12
DaveC426913
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Only for an hour. After that it gets tired.

And never anthropormiphise a battery. They hate it when you do that. :wink:
Yeah. Like I said, I'm not an electrical whiz. I'm not sure how to describe the verb that amps "do".
 
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  • #13
Averagesupernova
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It sounds to me like he has a voltmeter in series with the battery and himself. Not normally how you connect a voltmeter unless you are looking for really high resistance leakage. Without a drawing we can only speculate.
 
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  • #14
Klystron
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The OP may be interested in galvanic skin response. You can measure GSR and the voltage generated by your body without passing additional electricity through your body.

The wiki link refers to electrodermal activity (EDA) experiments. Be careful.
 
  • #15
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The current rating of a battery is the maximum it can supply before the voltage starts dropping due to its internal resistance. The current depends on the voltage applied and the resistance of the circuit. As a registered electrical worker, the official code I worked to was that anything below 32 V DC was considered safe. When AC is used, the frequency also has an effect because the impedance of the human body tends to decrease with increasing frequency, but at 50/60 Hz even 8V AC can be dangerous.
 
  • #16
nsaspook
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I'm not an electrical whiz.
That battery is rated at 2850mAh.
Is that tantamount to saying it can deliver 2.85 amps?
And, at 7 volts, is that enough to be dangerous?
That battery has a short circuit current ~ 50A. You will never get a body resistance at a value to draw 2.85A at that voltage unless the human body was carbonized and compressed into a solid thick amorphous carbon rod.
 
  • #17
Averagesupernova
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...unless the human body was carbonized and compressed into a solid thick amorphous carbon rod.
I doubt we'll need to worry about it at that point. ;)
 
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  • #18
Averagesupernova
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I would like to see a diagram of the 'setup' for this human flesh experiment.
 
  • #19
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I don't understand why this is but, If six people stand touching each other and the first touches a spark plug, the person last inline gets shocked and nothing to the in between. This is a very old school way to play with magneto electric. we've' done six or seven guys.
 
  • #20
Averagesupernova
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I don't understand why this is but, If six people stand touching each other and the first touches a spark plug, the person last inline gets shocked and nothing to the in between. This is a very old school way to play with magneto electric. we've' done six or seven guys.
From experience I can tell you this is not the case concerning electric fences which should very very similar to spark plugs.
 
  • #21
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From experience I can tell you this is not the case concerning electric fences which should very very similar to spark plugs.
I've been shocked by cattle electric fence And I will say I received more than one jolt with just me. I said I don't know why. :)
 
  • #22
berkeman
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Whelp, if this thread is going to go down the road of electric shock games, it's probably time to close it. Thanks everybody for participating.
 
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