Smartphones usually come with an AC adapter for charging. It plugs into an electrical outlet, and then plug the phone’s USB cable into the adapter.
The iPhone 4s has a really small AC adapter for USB-A, about the size of a walnut.
The Google Pixel 4a has a really big AC adapter for USB-C, about the size of a deck of cards.
Why is one AC adapter so much bigger? Something special about USB-C?
Thanks!
In: Technology
Power availability
The old iPhone 4 was being charged off of a 5V 1A charger so it needed to be able to output 5 Watts which isn’t a ton
The larger Pixel 4a charger can output 18W of power so it needs to use larger components that can handle the greater power levels.
More powerful chargers often have no choice but to be bigger for heat reasons too. Chargers aren’t perfectly efficient so a 90% efficient 5W charger is wasting about 0.5W of heat but a 90% efficient 20W charger is wasting 2W of heat which would make a small box very hot so they need to spread things out and give more surface area to shed heat through to keep things a happy temperature
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