Where do people get the PSU for their projects ??

[MathWizard]

Pretty much all the little projects I've made, that needed their own PSU section, I just used salvaged circuits and PSU's re-purposed from say stereo's and wall chargers.

And I've always been too cheap to order a transformer of any type, either linear or for switching, and they are at the heart of most any PSU section.

So what does everyone else do ? Do you re-use old junk like I do, or order a transformer and make your own? Or do you buy a pre-built PSU in a box ??

[ftg]

I either reuse junk, re-use some iron transformer from my junkbox, buy a MeanWell from TME.eu or just give the device USB-C.

[madires]

For projects which can be powered externally I go for common 5 or 12 V wallwarts (USB, barrel connector) and add a buck converter or linear regulator. If an internal linear PSU is needed, e.g. classic audio amp, I first check if I already have a suitable transformer, otherwise I'll buy one.

[themadhippy]

Do you re-use old junk like I do, or order a transformer and make your own? Or do you buy a pre-built PSU in a box ??

yes. It all depends on the project.

[rteodor]

Yep, it depends a lot on the project. When doing multiple boards I like to use these AC/DC modules. Just about any variant from 3.3V to 24V.

[rvalente]

Brick modules are also quite common as well.

https://www.hlktech.net/index.php?id=product&cate=cate703

[Driftless Engineering]

A wall-wart with a barrel connector is super easy if you aren't the type to lose the right cable for your project.

Most of the small things that only need 1-2 W I'll power at 5V with a USB cable, because I'm more likely to have a spare USB brick and cable than the barrel connector I need.

If you like a more finished product, I like to buy an AC/DC Converter from someone like TDK Lambda, along with a power entry module and cabling. That way I can just use standard C13 power cable you'd use for a PC.

You can find all of this stuff on sites like digikey.com and mouser.com.

[Doctorandus_P]

I've got a big bunch of laminated iron core transformers scavenged from long ago, and I sometimes use them for my own projects. But if I don't have a "fitting" transformer then I just buy whatever power supply is appropriate for the project.

I also dislike messing around with mains voltage for all the small projects. So I've put a 24Vdc power supply somewhere in a corner and made a home network that uses 24Vdc and Uart/RS485 for communication over CAT-5 cable. Each node has it's own small buck converter.

[NiHaoMike]

There's often high power PSU modules available for reasonably cheap on Ebay, particularly 12V and to a lesser extent, 48V. Those server PSUs and telecom rectifiers are built very well and even the used ones will last plenty long for hobbyist applications.

For low powered stuff, salvaged wall warts and USB inputs are often the way to go.

[Benta]

I used to do all of the above, but after the relatively new EU regulations on wall-warts, I'm gloriously happy. Best thing the EU ever did.
USB-C wall-warts are available OTS as 15...65 W types, and even up to 240 W as PD 3.1.
Why bother with PSU design? USB-C is compact, easy, small connectors etc. And with mass production cheaper than anything you can make yourself.
Forget barrel connectors, there must be at least 50 permutations, so you'll never have the right one.
Done deal.

[SteveThackery]

I used to do all of the above, but after the relatively new EU regulations on wall-warts, I'm gloriously happy. Best thing the EU ever did.
USB-C wall-warts are available OTS as 15...65 W types, and even up to 240 W as PD 3.1.

How easy is it to persuade these USB-C wall-warts to deliver those high powers? Isn't there some complicated negotiation required?

[ftg]

There is, but one can buy ready made "USB-C trigger" boards that do that for you.
Or use something like CH224.
3A 20V is 60W and 5A 20V is 100W, and that's plenty for many applications.
I have powered some nominally 13.8V radios with 15V sourced from phone chargers.

[rteodor]

There is, but one can buy ready made "USB-C trigger" boards that do that for you.
Or use something like CH224.

Sounds complicated. How much would it cost usually ?
Like the white PSU above 60W/24V was about 15 EUR. Simple and very compact with IP67.

[Benta]

Sounds complicated. How much would it cost usually ?
Like the white PSU above 60W/24V was about 15 EUR. Simple and very compact with IP67.

There are plenty of ICs out there that will do the job. As an example: ST STUSB4500. Will handle up to 20 V, 5 A. US$ 1.80 per 100 pcs.