How does a usb charger work?

:+1:
Thanks for another great write-up

Great writeup!! Really appreciate the time & effort you put into this.

You’re a wealth of information, many thanks!

You have my appreciation for the fine work you do in explaining how electromagnetic current can be modified in what might seem ‘magical’.

As J B S Haldane has been reported to have said, “Things are not stranger than you imagine, they are stranger than you can imagine”.

I am really impressed. :+1:

WOW!!!

Excellent. Thank you.

:+1: :+1:

subscribed :+1:

I’m eager to find the time to read this.
Thanks HKJ!

That was a great read :+1:

Very detailed article! Thanks!

Excellent article! I have no knowledge of electrical engineering, but I was still able to understand this article.

Is capacitor failure the most typical reason these chargers (and other consumer electronics) eventually expire?

I am happy to hear that.

Probably and when the capacitor fail it might kill other parts in the process.
If you look on you-tube for tv/monitor repairs, you will see that many of them starts by replacing capacitors.
Cheap capacitors placed at a hot location is a short-lived deal. On large multi port charges this will seldom be a problem, the number of hours that type of charger is hot is very low.

Hmm.
Have you ever heard about capacitor power supply (that are without transformer)?
95% of modern devices are equipped with them. And I think 99% of problems arise from them.

I would not call a capacitive dropper a real power supply.
They do not isolate from mains, i.e. everything is still mains connected and need the full isolation.
They have a very bad power factor.

But they are useful for small closed mains powered devices.

Thank you for this explanation. I’ll bookmark it. We have come a long way since the 4 diodes in a bridge plus capacitor.
And that was already radio-2.0 for me. Because my first kit radio had a triode… on batteries! What a disappointment. Many years later I found out that my father believed he had found a trusted source of almost-good-as-new zinc-catbon batteries.

uh…wow this is amazing.

Thanks for the write up HKJ and taking the effort to educate us all, some more than others I guess. :+1:

good job.
btw the sanyo 3300@10 is a fake.
something you will often see in this class of stuff.
all too familiar with the rfi issues mentioned by sp5it.
seems the easiest place to cut costs is the elimination of rfi/emi parts followed by output caps.
the first makes the unit noisy junk .
the second causes its early demise due to output caps blowing up.