Electronics > Beginners
PSU supporting both 120v and 240v.
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wraper:

--- Quote from: soldar on June 11, 2019, 06:51:56 pm ---
--- Quote from: wraper on June 11, 2019, 05:34:26 pm --- About TV, maybe, if it's small or really old. As of Laptop PSU, there is 99% chance it has PFC, unless it's Chinese knockoff. How do you even know that? You cannot take apart laptop PSU in non destructive way as covers are welded together. Did you actually measure current waveform?
--- End quote ---
You are not responding to my questions. You are changing the subject.  Again: Where is the regulation that says appliances over 75W need to have active PFC? Where? Because I am not saying it does not exist. I am saying the regulation that I have already cited twice does not require it. And between IEC_61000-3-2 and your vague and unsupported assertions I am afraid I have to go with the former.

And, yes, I have opened my Dell 90W power brick as I discussed recently in another thread. You can find it easily.

Again, look, it seems you just want to argue for the sake of arguing. I am not saying I am right. I am just showing the evidence that I have but you contradict it without any evidence whatsoever. Just show me where it says active PFC is mandatory in the EU. I will be glad to see it and learn. Please show us the evidence. What regulation is it?

--- End quote ---
I did not mean regulation requires PFC. Well, I was wrong about it being about power factor, it was about harmonics. PFC is a way how to do it relatively cheap and easy, maybe wording was not the best. Also it makes easier to get good performance out of SMPS part.

--- Quote ---You are not responding to my questions. You are changing the subject.
--- End quote ---
Too much ego on your side. IMO it was already clear what regulation was about. Yet I guess it's not enough attention for you to say about it only twice.

--- Quote ---you are not responding to my questions.
--- End quote ---
Which questions even vaguely addressed to me?  :-// I did not see a single one. I cannot read your thoughts.
soldar:

--- Quote from: David Hess on June 11, 2019, 07:09:29 pm --- The regulations do not specifically require PFC but instead specify a maximum input harmonic distortion for different power levels and classes.  Usually the most economical way to meet the specifications is to use active PFC although sometimes passive PFC is sufficient.

https://en.wikipedia.org/wiki/IEC_61000-3-2#Scope

Incidentally, industrial uses may be charged extra based on their power factor but doing this has been considered impractical for consumers so far.  So instead they regulate it on the supply side now.  It was not a big deal until switching power supplies became ubiquitous.
--- End quote ---
Yes, that's pretty much what I said.

I just realized I had not thought about my inverter split air conditioner units which I am pretty certain they would have active PFC.

To get back to the OP subject. Low power units like wall warts can have a wide ranging voltage input because efficiency is not of great concern.

Even laptop PSUs may not have active PFC because of space and weight constraints. My Dell PSU does not even have an inrush limiter and I have blown a few fuses in the UK until I inserted a PTC directly in series in the cable itself.

Cheap PSUs for PCs used to have the voltage doubler switch and now are just for a single voltage and do not have active PFC...

Because if they did the would be:

Higher range PSUs have active PFC which raises the voltage to a set voltage and this is in fact a pre-regulator and therefore admit a higher range of inputs (full-range).

Note also that Triac power controllers for incandescent lighting have some filtering but not what I would consider a lot.
soldar:

--- Quote from: wraper on June 11, 2019, 07:16:45 pm --- Which questions even vaguely addressed to me?  :-// I did not see a single one. I cannot read your thoughts.
--- End quote ---
Look, I do not enjoy arguing, with you or with anybody else.
Read the thread. For example post 24.
Again, I do not want to argue but you asserted some things and even gave specific numbers.
There is nothing wrong with me asking for a cite supporting that.
I never even said you were wrong. I just asked for confirmation and you ignored y question.
And you say I'm the one with ego?  Sheesh.
dcbrown73:
Thanks for the enlightening debate (argument?)  I learned a lot from my simple question!   ;D
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