making 3v ac adapter?

On Fri, 17 Nov 2006 11:23:32 -0800, snipped-for-privacy@gmail.com Has Frothed:

What will it power?

That depends on your skills and the tools you have on hand.

At any electronics store (like Radio Shack, if your local one still has parts) or on-line electronic parts vendor.

Use the other side of google for awhile - you can learn a great many things.

Good Luck! Rich

i haven't been able to find instructions on how to do it while googling

Rich Grise wrote:

Unless you already have the parts it's usually cheaper to just buy one. However, any book on basic electronics will give details on how to make power supplies.

An mp3 player that runs on 3v AC? Are you sure about that? Seems highly unlikely that any mp3 player would be AC rather than DC.

It'll almost certainly be cheaper to buy one ready-made.

As others have pointed out, such an adapter costs only a few (

It'd be a fairly simple project, but why bother? Unless it's 3am and you have the parts in your junkbox, it'd be like building a soldering iron. It's easier and cheaper to just go buy one.

yes

the cheapest place would be out of an adaptor...

mini transformer, with thermal cutout built in bridge rectifier, 1A reservoir cap, 4700uF @ 6v

If V_out = 3v, V_reservoir = apx 4v V_peak before BR = 6v tf v = apx 4v. So you want a 4v ac 0.7A transformer.

NT

On Fri, 17 Nov 2006 12:04:15 -0800, snipped-for-privacy@gmail.com Has Frothed:

Did you want to make it yourself to save money or just for something to do? It will probably cost less to buy one.

They're $1 each at Goodwill (secondhand store in the US).

Michael

If you need a DC output, Nokia's ACP-7U cell phone chargers are 3.7 VDC @ 340 mA. They are all over the place, cheap, or even free.

Yes. But why?

Any supplier.

What's wrong with Wal-Mart?

basically you need mains-to-3V, transformer. a plug, and a case.

a place that sells electronics parts. they may have pre-built ones for less than the parts cost.

what uses 3V AC ? 9V, or 12V is much easier to find

Plenty of portable gear (MP3 or CD players etc) that runs on 2 AA or AAA cells has 3V or sometimes 4.5V sockets.

It used to be when portable stuff used several cells, less so these days where 2 - 4 AA cell supplies are common.

Morse

Yahbut. Like he asked: what uses 3V _AC_ ?

All the 3.xV wallwarts I've seen for cell phones (and others) have been DC.

And, like a previous poster mentioned, there are crates of them at Goodwill, Salvation Army, ARC, and other second-hand stores. Folks break/have stolen/lose their cell phones at a somewhat higher rate than their associated wallwarts. :-) You may have to buy 2 of them: 1 with the correct voltage and one with the correct plug. Usually works out to be $1+$1 -- and it goes to a worthwhile cause.

Jonesy

Well, the poster I replied to said 9V and 12V were more common, he didn't specify DC ;-) If he'd said that 9VDC and 12VDC were more common than 3VAC I'd have agreed with him. My point is that low voltage wall warts like 3V are much more common than they used to be since MP3 players and the like became widespread. All my universal wall warts have a 3VDC setting.

Also, it is common for people to come to this group asking for an X volt AC adapter, when what they mean is an X VDC *AC adapter*, if you get what I mean. It's a very common mistake so it's possible the OP meant an AC adapter that puts out 3 VDC, but as he seems reluctant to take part in the thread he started and give us some useful info on what he wants to achieve, we may never know.

I'd put money on the OP needing a DC adapter, I can't see an MP3 player, assuming it's portable, having rectifier/smoothing cap in it rather than in the adapter, it'd be a pointless waste of space.

How his MP3 player will handle 3VDC from one of these cheapo unregulated wall warts is another matter. It may have been designed for this scenario, or it may have been designed for a 3VDC regulated supply available at an inflated price from the manufacturer.

They are a different ball game as they are custom made and are often SMPSs.

I have seen plenty of AC out adapters- the old NES and SNES games consoles had them for starters. It made sense and is good design practise to have the smoothing caps away from the hot transformer where possible. Obviously this is not often desirable in very compact portable equipment like MP3 players.

Morse