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
It’s all about the voltage and resistance. Electricity flows through an object proportional to the voltage applied, and an opposing force called resistance limits its flow. If you have an object with high resistance, you need a lot of voltage in order for any meaningful amount of electrical current to flow.
The output of your phone or electrical charger is between 5V and 20V. This isn’t enough footage to push through the resistance of your skin to the point that you feel a shock.
However, not all parts of your body have the same resistance. Your tongue, for example, has lower resistance because it’s tissues are saturated with fluids all the time. If you touch a 9V battery to your tongue, you will feel it. Touch the same battery to your finger and you won’t feel a thing. That’s thanks to the difference in resistance between the two.
Unfortunately there are a several incorrect answers here.
What makes mains electricity dangerous is the voltage. Electricity is a bit like water, and voltage is the water pressure. While technically it’s the current (quantity of water) that is dangerous to your heart, if the voltage (water pressure) is too low, the dangerous levels of current simply can’t be pushed through your body. So high voltage is like a pressure washer to your skin, and low voltage is like a bucket of water over your head. (Bad analogy, but consider just your skin – the bucket of water would wet your skin but it wouldn’t go through the skin into your blood like a pressure washer)
The chargers and usb connectors have a low voltage (pressure), and even though some can supply a very high current (amount of water) to your equipment, the pressure is not enough to get through your body and harm you. If you were mostly made of metal, (water analogy, you were made of sponge) it could harm you a lot more.
This is a great simplification, but it should answer your question.
ELI5: OUR SKIN!! Our skin is a wonderful organ that is quite resistive, so it takes fairly high voltage to penetrate it. The voltage in your phone charger is not nearly high enough to do so.
Electricity and water have a lot of useful comparisons. One of them is the similarity between voltage and water pressure:
Imagine that your charger is a drinking straw, and your electrical outlet is a garden hose. Electrical resistance is like obstructing the water flow; higher resistance = lower flow (current). If you squirt water through a drinking straw, it’s easy to completely stop the flow with your finger, but it’s much harder to completely stop the water from a garden hose with a finger, because the pressure is much higher. Your charger has a much lower voltage compared to a wall plug, so the same amount of electrical resistance (from flowing across your skin) permits far, far lower electrical current to flow.
Your muscles and nerves can react to electricity flowing through them, and if enough electrical current flows through your body, it can cause burns. Your skin’s electrical resistance doesn’t allow a meaningful amount of current to flow when a phone charger’s voltage is applied, but mains/wall voltage is high enough that your body can pass dangerous amounts of electrical current.
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