Exactly as stated in the title. All my life I’ve been able to touch my phone or computer’s electrical charger output (accidentally or for whatever the reason) with no sort of “buzz” or feeling from the electricity going through the output. At least that has always been my experience with it.
Just in case: Don’t intentionally try this of course.
In: 64
I can tell you don’t have an iphone because lightning is absolutely an appropriate name for those chords from all the times they have zapped me.
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* You usually need to complete a circuit (a round trip for electricity) to get shocked.
* Some plugs can easilly be attached to things (and hence more easily accidentally complete a circuit when you don’t want to), like alligator clips or bare wires or the wires inside a machine.
* However, many plugs for consumer electronics are designed so that it is hard to do that accidentally (the inside+outside of a charging cable, or two specific prongs embedded inside the wall).
* Many consumer electronics operate at low voltages, which has trouble getting past the barrier of your skin. If you bypass the skin, you canget shocked. e.g. licking a 9V battery will shock you, but touching it won’t (or rather, it will shock you so weakly you don’t notice). So, if you cut open your chest, and plugged a laptop charger directly into the pool of blood forming in your chest, I reckon that would shock you, as your blood seeps into the socket and touches both the inside and outside of the laptop charger, hence electrifying your blood.
It’s all about Ohm’s Law. Lower voltages (like 5V USB or even 12V car batteries) can’t ‘push’ much current – but higher voltages (like 120V power in the US or 240V in Europe) have more potential – the higher voltage can push more current through the same resistance (in this case your body) and you’re gonna feel it more. As an example take a 9V battery and put your finger across the terminals – you’re not gonna feel anything. Now touch that sucker to the end of your tongue – you’ll feel it! In this case the resistance of your wet tongue is far lower than that of your dry skin, so more current passes sufficient for your nerves to notice.
When you feel a buzz or tingle from electricity, you’re feeling the current
A USB port operates on about 5V (small). The resistance of your finger (assuming it’s dry) isn’t a very small amount. This results in a small amount of current, too small to feel.
A USB port also just doesn’t provide enough power to output a current that we would normally feel
Voltage isn’t high enough to push enough current to shock you or make a significant spark. Think of voltage as the pressure that pushes the current, as water pressure pushes water in a hose. Too low pressure (voltage) can’t push enough (water) current to be noticeable to you.
Additionally, your skin has fairly large “resistance” to the flow of electricity, similar to how a very narrow hose has more resistance to water flow that a firehose. Dry skin has very high resistance to electrical flow.
And that relationship between voltage, current, and resistance is called [Ohm’s Law](https://en.wikipedia.org/wiki/Ohm%27s_law).
Putting your hand under a pressure washer would hurt. High water pressure.
Putting your hand under a gentle faucet does not. Low water pressure.
The electricity coming to the wall socket is at a high voltage. Voltage is basically electrical pressure. This is dangerous.
The electricity coming out of a USB or other small cable has been reduced to a low voltage. This is safer.
In addition to all the other suggestions USB in particular only provides a very low voltage until a higher one is negotiated.
That negotiation can look very different depending on the USB version and/or quick charge mechanism, but can be as simple as having a specific resistance between two pins or as complex as a multi-step back-and-forth negotiation between the charger and the device. The one that’s most frequently used by Laptops and other high-power consuming devices is called [USB Power Delivery](https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Delivery).
So while USB on its own (without PD or any quick charge standard) can only deliver at most 7.5 Watt, with PD it can deliver up to 240 Watt, but only if the other side actively negotiates that. And the odds of your body “accidentally” following that protocol are pretty much null, so the charger will never deliver “full power” to your body simply by touching the cable.
ELI5 oversimplified, most of it wrong for demonstrative purposes
There are 3 things we need to look at when we talk about electricity.
* Voltage – The willingness of the electricity to go from point A to B
* Amperage – The amont of electricity flowing
* Resistance – is well the resistance of something against the flow of electricity. This fights against voltage
Electricity always want to flow from where there is more of it to the point where is less.
For the “buzz” to occur you need to have enough Voltage to overcome the resistance enough so that the amperage could flow
Your skin has pretty high reistance, an USB charger doesn’t have enough voltage to overcome it. But an electrical socket has more and that is dangerous.
Also you could try if you have a 9V battery. if you press it on your skin, nothing happens. But if you lick it, your moist tongue has much less resistance and there is gonna be a buzz.
If you lick a 5V charger there should be a metallic taste with a tiny buzzing.
DISCLAIMER: ALWAYS BE CAREFUL WITH CHARGERS PLUGGED DIRECTLY TO A WALL OUTLET.
there are several reasons:
– current type: DC (direct current like from a battery or your phone charger) is not as good at delivering an electrical shock as AC (alternating current, like you get from your wall outlet)
– voltage (like water pressure): lower voltages (like the 5 volts from a traditional phone charger), cannot travel through skin under normal circumstances. higher voltages are more effective at traveling through more difficult things like dry skin, and even the air. (current from tesla coils is in the thousands of volts and can shoot several feet through the air)
9 volts DC (like from a 9v battery) is still not enough to shock your skin, but if you touch it to your tongue, you will feel tingles. so on the other side of things, you have the material electricity needs to travel through. they all have different levels of resistance. if they let current pass through easily, they’re called conductors. if they’re good at resisting current flow, they’re called insulators. rubber, air, and glass are good insulators of electricity. metals like copper and aluminum are good conductors of electricity. dry skin is not, but the wet skin of your tongue is a bit better, and just enough to where you can start to feel a small shock on your tongue
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