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So what exactly would happen if you put the connector of a plugged-in charger in your mouth? I am sure it is a bad idea but can it really hurt or even kill you?

Some posts on social media led me to this question.

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  • \$\begingroup\$ what kind of charger are you talking about? 5v phone charger? I'm not sure about this exact case, but you remember that 4.5v batteries? You can put your tongue on it and you will feel the current going through your tongue, it feels kinda like you eat something sour(lemon, sour candies). But no problems at all, used to do that a lot when I was kid. You can google what is the maximum current from that 4.5 battery and compare it to charger, if it is not very differnt, then I suppose the feelings would be similar. Sorry I can't google it for you, have to go now. \$\endgroup\$ Commented Feb 11, 2015 at 5:44
  • \$\begingroup\$ I just measured the resistance of my tongue and it's somewhere around 70-100 kOhm, so I seems kinda difficult to make serios damage, even if resistance is 50 kOhm, then the current would be 0.1 mA, the shock and pain usually starts from currents above 10 mA... and death is 100mA(and it usually needs to go through heart), so you would need higher voltage to make it \$\endgroup\$ Commented Feb 11, 2015 at 5:54
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    \$\begingroup\$ I don't suggest anyone to try this. Just answer if you know the answer. :) \$\endgroup\$ Commented Feb 11, 2015 at 6:28
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    \$\begingroup\$ When I was a kid, we used to touch 9V batteries to our tongues, just like ScienceSamovar describes. It is similar to a sour taste. Usually you can only hold it there for a moment, because it is a little bit unpleasant. So if the voltage was much higher than 9V, maybe it would be painful or something. But if it is 9V or less, I think it would be very mild. \$\endgroup\$
    – user57037
    Commented Feb 11, 2015 at 6:47
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    \$\begingroup\$ This is kind of like asking "how long is a rope" or "how fast is a car?" It depends. What charger for what application, connected to what kind of power supply? \$\endgroup\$
    – Lundin
    Commented Sep 6, 2016 at 13:05

4 Answers 4

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This is not the same as putting the terminals of a battery across your tongue. Modern wall warts/chargers are likely to have an open circuit voltage to earth (on both output conductors) of many tens (if not hundreds) of AC volts due to the way they are constructed. Normally this isn't a problem because the impedance behind this voltage is quite high.

I would expect that putting one or both terminals on your tongue would be slightly more shocking that the equivalent battery.

As a side note, this AC voltage is due to the way EMI filter components are used - at regular AC frequencies they are fairly high impedance (tens of kohm) but they will give a bigger than expected jolt on the tongue and this is not to be recommended.

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  • \$\begingroup\$ I think you can write an answer that is two to three times better (and somewhat deep). Waiting for it and leaving the comment to catch your attention. \$\endgroup\$ Commented Feb 11, 2015 at 9:40
  • \$\begingroup\$ @VladimirCravero please feel free to add to this \$\endgroup\$
    – Andy aka
    Commented Feb 11, 2015 at 11:09
  • \$\begingroup\$ well the point is I like your answers more than mine, I'll think of something maybe \$\endgroup\$ Commented Feb 11, 2015 at 11:11
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It causes a very unpleasant, painful even, sensation if the adapter output voltage is high enough. I can say this for sure because I tried it. When my son was an infant one time he was sitting happily on the floor next to my desk chair while I pounded away at the keyboard on some kind of engineering stuff and briefly started to cry a couple of times. Turned out he was picking up a loose end of an AC adapter and putting it in his mouth. I tried it on myself to see what he had experienced (I think it was more than 12V- possibly 24V for an EPROM eraser). Quite painful. 5V would likely not be too bad judging from 9V batteries. Andy has a valid comment that the Y capacitor reactance on an isolated may cause some sensation (I think it wold be slight, but I'm not going to try it) even touching a single side depending on how the adapter is plugged in- it would be more noticeable in a 240V country.

I certainly don't suggest doing this yourself, however it's unlikely to be anything but unpleasant, depending on voltage, if the adapter is working properly. It could, however, be fatal if the charger were to be faulty and there was was a path to earth through the body. This is an increasing possibility with the proliferation of criminally bad overseas-made chargers, such as the fake 'Apple' ones that sell for $1 including airmail, with fake safety agency approvals and definitely dangerous internal construction. A similar device is already known to have killed a woman. It's far more of a danger than with dry hands because your skin resistance is less inside a wet mouth.

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    \$\begingroup\$ "...while I pounded away at the keyboard on some kind of engineering stuff and briefly started to cry a couple of times." - I had to read this a few times to realize that your son was crying, not you! \$\endgroup\$
    – Greg d'Eon
    Commented Apr 22, 2015 at 12:13
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OK this is not really an answer, but the videos by "Electroboom" are a hoot.
https://www.youtube.com/watch?v=hp97GjuULX8

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The impedance of body is non-linear and time variant. It is non-linear, since it depends on the applied voltage, a higher voltage might result in a lower impedance! As said, it is also time variant. At first, when one puts a DC source on his body, electrical resistance is relatively high (a few mega-ohms), after a few moments ions in the blood stream approach the positive and negative poles. This facilitates electrical conductance in the body. After that, the body impedance lowers and more current passes through the body. This makes a positive feedback and more ions populate the pole sides and hence even more current passes through the body. This all was about skin stimulation, however situation in mouth is a little bit different. Impedance in mouth is not too high , since the saliva makes mouth surface a good conductor, and in addition, the mouth texture is made by membrane cells, which are more near to the blood stream (which thanks to ios floating, is a very good conductor). The placement of DC poles are too important, if their in a setting such that a current path is made through the chest, the heart might be in severe danger. Since the poles of the charger are too close to each other, I do not think it affect the heart. Remember even if the charger is protected against high current draw, it is still to dangerous to humans! In a nut shell, if the charger voltage is low and the exposure time is also short, no critical damage might occur but if the voltage is high and/or exposure time is long, severe damage might occur.

Wiki Refrence

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