Hi all, i was thinking about those little cellular phone chargers and how they use those tiny transformers to supply 5v @ 500ma.
Where can i find these kind of transformers? I was thinking about just buying a bulk amount of chargers and taking the boards for my project but i would love to find out how and where to get the parts.
I live in US so its a normal 120v-125v from wall so i need something to step down that. So any links to possible solutions would be cool!
Remember my goals:
1. Small size/form
2. 5-12v output would be great.
They aren't mains transformers, they are high frequency switch-mode transformers as part of a SMPSU.
As every single circuit uses a custom transformer you can't usually buy just the transformers, and the assoociated electronics to make them wiork would make it far more expensive than buying complete PSU's.
Atom, **broken link removed**
and down load app. note RDR158 and design RDK160
PowerInt has many designs for low power switchers, usually includes the transformer disign.
I bought some name-brand, 5VDC-2A tiny and lightweight switching power supplies at a surplus store. They were made for dial-up modems (remember them?). I paid less than $2.00 for each one and they had thousands of them.
I also have some similar ones that were cell phone chargers.
The big problem with transformeless supplies is there's no current limiting inherently built in like with a transformer, if a component fails or it takes damage from a fall or what not bad things happen.