No seriously, I always get blank stares when I ask people, I’ve called them wall chargers or power bricks, my friend called them plug chargers, my fiancee calls them dongles. What do you call these around your house, like when you’re asking someone if they’ve seen any (______)'s
I’d call them USB adapters; “chargers” is probably slightly more common though never sat right with me since they can be used to power things other than charging.
Or more in the past we would call any kind of power adapters “transformers” but don’t seem to hear that much any more.
Technically they are power supplies.
A transformer can be a power supply, but on it’s own it can only transform AC power between two different voltages, so it can only be an AC:AC power supply. The number of windings on one side vs the number on the other, will determine the ratio of your voltage change.
But a pure transformer AC:AC power supply is not particularly efficient. A transformer’s power rating is based on the overall number of windings it has, and on the power frequency.
So if you’re lowering the voltage, it’s more efficient to use mosfets to chop up your voltage at a very high frequency, then run that high frequency voltage through a smaller transformer.
And with DC power supplies, they not only need to lower voltage, but also smooth it out to a single unchanging value, and this results in an even more complex circuit where you first rectify the wave so that it’s all on one side, then you chop it at high frequency then transform it, then smooth it out.
So transformers are still involved, but typically they’re just one part of a larger whole with these.
Yeah, I’m sure you’re right, my comment about transformers I guess was more about colloquial usage, i.e. rightly or wrongly we called DC power supplies transformers in the 90s. I also don’t know how local that was, maybe it was just my family!