Eli5: How are phones waterproof even though the charging port terminals can be exposed to water and not short circuit them?
The ports are insulated and covered in hydrophobic material (material that naturally repels water). Also, charging ports could still short in that situation so many phones have sensors that stop the port from accepting electricity if moisture is detected inside the port.
As others said “water resistant”.
But for the ports, there’s a few tricks the most commonly used is to have moisture detection in the port. This is pretty trivial, basically you have a circuit that measures capacitance and if that circuit detects a change in capacitance (there’s a big difference between the capacitance of air and water) then the phone will disable the port as well as the ability to charge the phone until that’s no longer the case.
No power in the port means no short circuits.
Of course, your ports are still vulnerable to corrosion from exposure to water but the components in a phone are decently resistant to corrosion.
They put a nano coating of this tiny hydrophobic liquid around the seems and port of the phones. This makes it so water dosen’t want to touch the phone in the first place and can’t “stick” to it so to speak.
This nano coating is basically just a type of glue. Most brand new phones can survive hours submerged underwater because the seals around the phone haven’t been abused yet. The older your phone the more time it’s been dropped, had the hot and cold thermally expand and shrink the phone’s materials breaking the bond of the seams.
Swimming with your phone can put enough stress onto the material and force water into your phone. Kinda like pressurizing the water into the phone in a way. The deeper the phone goes in a pool (hypothetically) the less chance of that phone surviving due to the increase of pressure. (I’m sure you’ve had your ears build up pressure when you dive into a deep pool, same idea as that).
There is no insulation in the connector, water will prevent the ports from working and if you keep trying to charge it when wet, voltage and water working together will quickly corrode the contact pins.
However it is still water resistant by mechanically sealing the whole connector and in fact any holes and cracks for buttons, speakers and the screen, preventing any further liquid ingress into the phone.