Computer PSU transformers

[Joel Rainville]

I recently dismantled an old computer PSU, and I am surprised to see some pretty smallish transformers. I'd like to experiment with those, but I'd like to make sure applying 110V to them is safe?... They look so tiny...(see attached photo)

Googling the markings on them doesn't turn up much except for that **broken link removed** on crappy PSUs.

I have a few DS01S bridge rectifiers (max 70V AC on input) and various fixed and adjustable linear regulators from Fairchild, and if I could derive 25-50V AC from the biggest transformer, I'd like to try and come up with a little fixed voltage power supply for my prototypes.

Any thoughts?

 

[JimB]

Joel

Applying 110v 50/60hz to those transformers will destroy them.
They are from a switched mode PSU which runs at a high frequency, several 10s of khz.

Higher frequency needs less inductance hence a smaller, lighter, cheaper transformer.

Quote:
"sorry Brits, couldn't find any pences "

No problem, money is money, I will accept all the Euro you can send me.

JimB

 

[Joel Rainville]

Applying 110v 50/60hz to those transformers will destroy them. They are from a switched mode PSU which runs at a high frequency, several 10s of khz.

Higher frequency needs less inductance hence a smaller, lighter, cheaper transformer.

Ok, I am glad I asked first :lol:

I do have a few paper bills from Scotland, but I will be keeping those if you don't mind :lol:

 

[Joel Rainville]

So, in that PSU, the 110V AV was going through a bridge recitifier *before* hitting the switching transistors and the transformers, right?

 

[Nigel Goodwin]

So, in that PSU, the 110V AV was going through a bridge recitifier *before* hitting the switching transistors and the transformers, right?

Yes, sort of?, it's the standard switch-mode technique - usually though PC supplies are switchable 110V/230V. So the incoming mains is switched to be a bridge rectifier for 230V, but a voltage doubler for 110V - crude but effective!.