im presuming i need a bridge rectifier, anything else? capacitor?

better still is there an 'all in one' uni that gives me a smooth regulated dc supply from 12vac?

12vac is 1.3A by the way.

thanks for help.

ben

 

Do you have a 12 V transformer?
Then you will have 12 Vrms which is approximately 16.9 Vpeak.
You need rectifier (not necessary bridge), filter capacitor and voltage regulator.

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Superman returns..

 

They're called power supplies =) Sounds like what you're looking for is a generic regulated wall wart without the 10-1 down conversion transformer, you should be able to take apart and modify any 12 volt regulated wallwart and use that. There are hundreds if not thousands of circuits available on the net using google or your favorite search engine rather than rehash this very basic question you should probably go search through the circuits you can find using those.

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OK, I have a power supply which is 12vac. which runs an AC motor. Then I have stuff which runs off 12vDC. So rather than buying another power supply, i would like to turn the AC to DC.

Im presuming that after the AC has been converted to DC I get a voltage drop, would this be true?if so by how much?

Thanks 'bananasiong' "You need rectifier (not necessary bridge), filter capacitor and voltage regulator", is there a single chip which will do the conversion for me without the need for all these components? it seems like it should be a common problem, so im presuming there is a single solution kicking round?

I have searched on the web, and I cant find anything. Yes I am a noob, and i apologize if this Q has been asked 100 times, but I have tried to research, but I dont really know exactly what im searching for. Any help would be appreciated.

ben

 

Im thinking of usung this component... http://cpc.farnell.com/jsp/Component...?sku=SC2KBP005

it conjunction with ...
http://cpc.farnell.com/jsp/Component...sp?sku=SC05419

What would the specs on the filter capacitor be?

 

The size of the filter capacitor and heatsink for the voltage regulator depend on how much current the 12VDC must supply. How much?

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Uncle $crooge

 

the 12v DV device is 1 amp

 

Is your device a DC motor? Is constant 1 A drawn all the time?

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Superman returns..

 

I have a 12VAC Motor which runs from the original 12VAC power supply.
Then a 12VDC radio, which was originally running from a car battery.

So im thinking this capacitor would sort out the DC 'ripple' after the bridge rectifier...
http://cpc.farnell.com/jsp/Component...sp?sku=CA00550
???

 

For an output of 12VDC at 1A, you need a 12V transformer rated at 1.4A.
It will be overloaded if it drives a motor in addition to the 1ADC load.

EDIT: A radio? It doesn't play at full blast all the time so it doesn't draw 1A continuously. The 1A transformer might be OK if the motor doesn't draw much current.

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Uncle $crooge

 

If I am not too obvious here are few points that do not figure in the discussions. You DC rectifier would multiply AC suppply voltage by about 1.4. So your DC output using 12 V AC transformer output would be about 16.8 volts as some one has already said. If you want 12 V DC from that, you can use a simple and cheap voltage regulator 7812 (that has 3 pins- input common ground and output). The output will be exactly 12 V. The chip can sink 1 Amp easily if you put it on heat sink. Make sure that you use at least 2000 mfd (35V) capacitor across bridge output and 220mfd 35V cap across regulated output. The output will be suitable for any 12 V DC device (including your radio).

Was this reply too long and unwanted?

 

No not at all, it clarified much for me. Thanks