Why is it safe to touch the electricity-outputting end of our phone and computer chargers with no sort of electric shock on us as opposed to other dangerous electrical outputs?

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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.

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Anonymous 0 Comments

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.

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