And then there is the voltage conversion, which traditionally happened on the AC side (inexpensive and simple AC transformers are generally why the transmission and distribution systems are AC). Modern power supplies allow for buck/boost on the DC side.
USB-C power supplies are above 90% efficient. [1]
[0] https://eepower.com/new-industry-products/huawei-claims-most... [1] https://www.ti.com/lit/ug/tidudw2c/tidudw2c.pdf?ts=168350042...
That's a really strange thing to see here on HN. Where did you get this idea?
BTW Europe having 3-phase AC to the home is brilliant. Wish we had that in the U.S.
Are there three phase sockets available? I'd think you could build things like high power audio amplifiers or power supplies at radically better price points, if this were actually usable from the wall in places.
3 phase is 120 degrees out of phase. Wall power only has a single phase, 360 degrees. Via +/- rectification the situation gets more complex. The key thing, as the other commenter points out, is that there is always always power available. Where-as with wall-power you literally drop to zero voltage as you go + to - & back.
Why is this strange? I see this kind of ignorant nonsense here all the time.
This site is absolutely full of software people who, because of Dunning-Kruger, think they're experts at everything technical. Electrical engineering isn't that far from the software world (computers are electrical, and their design is within the EE world), so software people frequently think they're experts at anything EE when in fact they don't even understand Kirchoff's Laws, much less the realities of modern-day AC and DC power transmission.
There's been multiple discussions here in recent months with these people advocating absolutely idiotic stuff like a whole-house 5V DC supply, showing they don't even understand Ohm's Law.
On a side note, it's very frequent that I see posts here from people who apparently have never heard of an ad-blocker, yet are complaining about ads.
Theres a reason why china is spinning up DC power grids while posts like mine get bashed on.
If you're AC all the way, there's never a need to rectify your generator, either.
However it's not uncommon for this to be enforced by law, for example it is a legal requirement that in the UK all goods sold must adhere to the BS 1363-1 standard.
Every few years the National Fire Protection Agency (NFPA)--which is a non-governmental nonprofit--publishes an updated standard and then it's up to all the state legislatures to update the laws to require the new standard.
The problem is that the NFPA doesn't just post the NEC for free on the Internet. You have to pay for it (which is ridiculous) and it's copyrighted and as such, illegal to just give away. There was a lawsuit in Georgia that was supposed to determine whether or not that situation was OK (having laws that require expensive fees to view may be unconstitutional since that's like having secret laws). I don't know what the outcome was of that though.
The Supreme Court in 2020 ruled that OGCA is not copyrightable, this in 2022 indicates that it has been made available to the public for free.
There are four states who have not adopted the NEC on a statewide basis, leaving any such decision to the local authorities having jurisdiction: Arizona, Illinois, Mississippi, and Missouri.