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How do I buy quality external power supplies ("Adapter"/"Wall wart") from China?
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BeBuLamar:

--- Quote from: John_doe on February 21, 2022, 10:38:32 am ---
--- Quote from: BeBuLamar on February 20, 2022, 03:51:18 pm ---How much is sane price? I would think $20 is still a sane price.

--- End quote ---
Well, I guess that for an adapter of, lets say, 30W, $20 including shipping sounds like a fair price. Not a great price, just a fair one. But even that price I was unable to find.




--- End quote ---

300mW or 30W. 30W is a relatively big walwart.
tunk:
What will it be used for?
If it will replace an old type PSU (transformer+rectifier+capacitor) used
to charge a battery, then an SMPS will not work (it may sort of work with
a suitable resistor in series). Some equipment may work with slightly
lower or higher voltages, so it may work with a 9V adapter.
rdl:


--- Quote from: tunk on February 21, 2022, 02:01:56 pm ---What will it be used for?

--- End quote ---

This is a good point. What is this adapter going to be used with? For example, here in the US they love to use 9 or 12 volt adapters with things like routers, cable modems, external disk drives, etc. Then, first thing that happens inside the device is the voltage is regulated down to 5 volts or less.
tooki:

--- Quote from: rdl on February 21, 2022, 03:01:38 pm ---

--- Quote from: tunk on February 21, 2022, 02:01:56 pm ---What will it be used for?

--- End quote ---

This is a good point. What is this adapter going to be used with? For example, here in the US they love to use 9 or 12 volt adapters with things like routers, cable modems, external disk drives, etc. Then, first thing that happens inside the device is the voltage is regulated down to 5 volts or less.

--- End quote ---
That’s not a US thing, that’s how it works worldwide. The whole reason for that arrangement is for the device itself to not require local safety certifications for each country, instead relying on an external power supply to handle that. Saves money.
Zero999:

--- Quote from: wraper on February 21, 2022, 10:46:57 am ---
--- Quote from: SmallCog on February 21, 2022, 02:18:26 am ---Basic options:

1) Buy from online marketplaces such as ebay/ali/bangood/wish etc. and roll the dice that you'll get what you ordered and it will be safe

2) Buy the above with the skills/experience/knowledge to open the device, assess its safety, and either make the appropriate alterations or dispose of it and try again.

--- End quote ---
Unfortunately that is not enough. A lot of them may look OK on a first glance, however transformer may easily lack any serious insulation or QC even if construction is somewhat decent. Only Hi-pot test will show if its electrically safe or not.

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I wouldn't even trust a hi-pot test for a dodgy, unknown transformer. It might pass, but that doesn't mean anything. If they used crappy insulation and too thin wire, it might get hot, melt and arc over during normal operation. The only way is to take a few to pieces, look at how it's constructed an the quality of the materials used.
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