Miniature transformer/stepdown-regulator

"Iman Habib"

** Really - explain how come.

Your whole post seems very sus.

........ Phil

"sus" what? why?

I do not want galvanic isolation to reduce size. It's a thingy that is supposed to fit inside a lamp switch socket hole. So i have very little space to work in.

//iman

"Iman Habib"

** Why did you just snip everything that mattered out of sight ?

Got a lot to hide?

** That is a BIG FUCKING DIFFERENCE from not *needing* it.

Answer the question I posted.

If you can.

......... Phil

You have good triple insulation? If you really don't need isolation you don't need a transformer. Look up buck converters, you'll find plenty of 340vdc off-line ICs. At this point I'm ready to list four or five key considerations. But let's just say there are serious pitfalls, it's best to hire an experienced engineer.

What's your project, tell us about it.

--
 Thanks,
    - Win

What's inside the switching chargers Nokia & others manufacture for mobile/cell phones? Might be worth a starting point.

There is no need for you to be impolite Phil. I have nothing to hide so calm down. Why are you being so suspicious?

I'm an EE student from Sweden that is just helping out a friend of mine for some project. He wants to shove a small computer and some other stuff into a switch/socket. Don't ask me why he wants to do it. I don't even care and its really not that fascinating to be honest.

Obviously you are not capable of helping me out so I'll just wait and hope somebody else will give me a pointer. Don't bother replying Phil if you are just going to swear and shout at me.

Have a nice day (you seem to be in desperate need it)

//iman

Yes. I am actually opening one right now. =) But the little bugger is kind of hard to open. Ah well.. time for the big hammer.

thanks //Iman

Sorry for the confusion win. I really suck at using the right tehcnical words. You are absolutley right. I dont need a transformer.

As i said to phil. I am just helping out a friend of mine for some project. He wants to shove a small computer and some other stuff into a switch/socket. Don't ask me why he wants to do it. I don't even care and its really not that fascinating to be honest. :-P

Anyway. I google around for "buck converters". Thank you for your help.

//Iman

If it is a hobby project, I would design it with proper isolation. I lost a good friend because he was also sure he didn't need the isolation...

The biggest problem with buck converters is that you'll need a really small on-time (approx 1.7%). This decreases efficiency and you'll need to find a high voltage MOSFET which you can switch fast enough to meet your requirements. Keep in mind the MOSFET must be able to conduct the maximum current in the load.

--
Reply to nico@nctdevpuntnl (punt=.)
Bedrijven en winkels vindt U op www.adresboekje.nl

Hej! :-)

There are quite a few applications that do about the thing you are looking for, if you look at dimmer or phase controller application notes on the controller chip manufacturers' pages. They usually use a small capacitor for voltage division.

--
http://www.flexusergroup.com/

"Iman Habib"

** Get f***ed you bloody fake.

** Got any bombs tied to you ?

** The get him to post here.

Meanwhile - YOU can f*ck off.

** You are an obliging criminal ass. ** You are a DAMN LIAR .

........ Phil

"Iman Habib"

** Get f***ed, you trolling GG ASS.

....... Phil

"Iman Habib"

** You are a FUCKING Googlegroping LIAR !!!

........ Phil

""Bjarne Bäckström""

** Gawd - another obliging wog f****it.

** ROTFL.

One that gives several amps DC of the AC supply ?

The Tooth Fairy sells them.

........ Phil

We're sorry about your friend. As for Iman - he should tell his friend our strong advice is that he remove the conduit switch box, get out his saw and install a double box. Then he can use safe small commercial power modules such as those made by Astrodyne,

--
 Thanks,
    - Win

Hi.

Single-chip ICs versus multi-chip ICs? Your "friend" would be well-advised to loose you, you're worthless; talk about the blind leading the blind. Why don't you try prototyping a beefed up variant of this:-)))

Phil does seem to have some kind of compulsion to be impolite. I want to see if his rather restricted range of impoliteness has improved over the past few months, so I'm intentionally provoking his ire.

A sensible request, addressed to someone who isn't responsive to sweet reasonableness.

Paranoia might be a plausible explanation - though there are a bunch of conditions associated with "rage attacks" whch migh explain Phil's behaviour.

He is.

Still, he's probably right to warn you about the dangers of non-isolated mains-driven circuits. They are only to be considered if you know exactly what you are doing, and even then you have to keep in mind how you circuit might be abused by someone who thought they knoew exactly what they were doing. He's abused me roundly in the past for not being as defensive in such matters as he would like, and while I didn't think much of his logic, his rabid advocacy may raise enough consciousness to save a few lives

--
Bill Sloman, Nijmegen

Well I would advise him to loose me to. =)

I am more used to play around with non lethal current/voltage levels so I have unfortunately very little experience when it comes to making anything that is supposed to be directly connected to a household AC net. But I reasoned that it would be a good learning experience to read a bit more about it and try to solve it instead of passing it on to somebody else.

Of course I am aware of the dangers and have no intention of plugging in anything before somebody (a teacher for eg) double-checks my simulations/calculations.

Anyway I have already come across the schematic you pointed out but it did not quite reach me needs.

Thanks anyway.

//iman

The Astrodyne ultraminiature modular switching power supplies seem to be a very sensible option. Actually it's a great option. Thank you very much for the pointer. I will advise my friend to use one of these.

But I will still pursue to learn more about switching power supplies and try and implement one myself. It's best I get my hands a bit dirty and learn something about this the sooner instead of later when it may be in a more serious circumstance.

Again, thank you.

//iman