220 V ac to 12 V dc 3 Ampere

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Hi.
I need to convert 220 V ac to 12 V dc 3 Ampere.
could you please give me a schematic for that?
thank you

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A transformer followed by a full wave rectifier (diode bridge) plus a larger filter capacitor.

Ross McKenzie, Melbourne Australia

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thank you for your reply.
could you please give a schematic for that circuit?

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This is pretty fundamental - was google not able to help?

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You are aware that 220V is potentially lethal :!:

If your understanding of electricity & electronics is really at the level where you need to ask this, I would strongly suggest that you do not attempt to do this yourself :!:

Buy a ready-made power supply - it is unlikely to be (much) more expensive than building your own, and will certainly be much safer :!:

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nta_xyz wrote:
thank you for your reply.
could you please give a schematic for that circuit?

http://en.wikipedia.org/wiki/Fil...

And as others have said, if you do not understand this level of the fundamentals, perhaps you should seek some onsite help unless you want to risk serious injury or death. BE CAREFUL!

Ross McKenzie, Melbourne Australia

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Kartman wrote:
This is pretty fundamental - was google not able to help?

I could not trust!! the circuits that I find in the google! and because of that I asked my question here.

I would like to make this circuits by myself so if you have a experience in this case please let me know.
thank you.

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nta_xyz wrote:
I could not trust!! the circuits that I find in the google!

Why not?

What doubts do you have?

Quote:
if you have a experience in this case please let me know.

Anyone with experience would know how dangerous this can be - so would not encourage a novice to attempt it alone.

You really need to find someone local to supervise you in person and ensure your safety :!:

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What country/city are you in? Perhaps there is a local radio club or hackerspace where you could seek help.

We don't want to lose you.

Ross McKenzie, Melbourne Australia

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Buy a commercial AC plugpack that outputs ~12VAC such as this one:

http://www.digikey.com/product-detail/en/BPE2E/BPE2E-ND/454399

The high voltage side of things will be handled by that thing, meaning you have less of a chance of killing yourself by electrocution.

You can do the rest of the circuit yourself.

- S

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Please note that mnehpets's link is for 120V AC and 12V AC output.

You really should NOT buy anything that you do not understand. And you should certainly NOT attempt to build anything.

Ask your schoolteacher to help you. Or join a local robot / radio club.

David.

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I just went to www.ebay.de and typed nothing but "12V 3A" into the search box. It hit 3,405 items. I imagine one of those is going to do the job for you just fine. Expect to pay from €2.50 upwards (probably less than you could buy components and make a PCB that would probably kill you!).

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mnehpets wrote:
Buy a commercial AC plugpack that outputs ~12VAC

Absolutely.
That way, the only bit you're not doing yourself is the dangerous bit.

Do be careful to buy something suitable to the mains voltage where it will be used :!:

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Where will it be used?

Imagecraft compiler user

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Quote:

Where will it be used?

There was a very subtle clue in my post ;-)

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Oh. OK. Nevermind. (Emily Latella, circa '70)

Imagecraft compiler user

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What accuracy is needed? Does it have to be 12.000V? Or, can it be 12.5?

Can the voltage change when it goes from no load to full load? For example, could it be 13V at no load and 11.9V at full load?

Continuous or intermittent operation?

For your personal use or to go into some product?

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

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thank you all :D now I scare:D to do anything about this project :D

ka7ehk:
I made a pcb which has a sim900 and xmega and some relays. now my power of my pcb come from a adapter which convert 220v ac to 12v dc and in the pcb i convert 12v to 5v and 3.3v by regulators.
but now I would like to have the adapter part in my own pcb.
is it possible?! :D

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There are standard rules for grounding, wire and trace sizing, fusing, and isolating the mains part of the PCB from the low voltage part. If you don't follow those rules that PCB would expose you for liability and not be allowed in any public market or structure.

But if just for your own personal experimentation have at it, that's how you learn. Use sensible precautions like ground fault interrupters, isolation transformers (not variacs, don't ask me how I know), one hand in pocket, dry rubber shoes. Then hopefully the 220 volt shocks will be a valuable learning experience.

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@nta_xyz,

Everything is possible. You do not appear to have much knowledge of electronics or safety.

So I suggest that you stick with your commercially made adapter. This will (hopefuly) have passed European safety tests.

If you intend to sell your "pcb", it will need to satisfy European safety tests.

If you just want your "pcb" for personal use, ask your schoolteacher for hands-on help. This will involve staying awake in your classes.

It would be wrong for us to assist you remotely.

David.

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Haven't you noticed how much commercial equipment uses an external power supply - so that only low voltages go into the box and onto the PCB?

One of the reasons they do this is to avoid the safety issues of putting mains inside the box.

If experienced people who do this for a living like to avoid dealing with mains - don't you think it might be even better for a novice to do so... :?: :!:

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  3. Wrong baud rate is usually due to not running at the speed you thought; check by blinking a LED to see if you get the speed you expected
  4. Difference between a crystal, and a crystal oscillatorhttps://www.avrfreaks.net/comment...
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If i was REALLY pushed for a budget solution, look at using an old laptop computer psu. These are usually 17-19V. On some there is a potentiometer that adjusts the voltage. On others a change of resistor calue will adjust the voltage. There's probably something on the interwebs with pictures on how to do this.
Or look at power bricks for other devices like scanners or inkjet printers - you might find one around 12V.

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Long ago it was common to put a Mains power supply inside the case, (fuse, switch, transformer, bridge rectifier, caps, etc.).

Now days, for a uC PCB which draws relatively low current, the general approach is to use a "wall wart" or power brick and just supply the low voltage DC to the project. You PCB can then generate the 5V and 3V power supplies for the circuitry.

If building this for your own project it is certainly doable to build your own 12 V DC supply. But if you already have an Xmega PCB, then most would focus n the micro, and use a pre-built, commercial, power supply.

JC