12v 3a Transformerless Power Supply

uchihahayato

Aug 31, 2010
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Aug 31, 2010
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Please Help me. I need a schematic diagram of a Transformerless Power Supply.

With the following specs.

Vin = 220V AC
Vout = 12V DC
Current Rating = 3 A

Please Please Please  :-\

 

Hero999

Oct 28, 2007
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No because it's not practical.

Take a typical transformerless power supply circuit:
Transformerless-power-supply.png


For 3A@12V C1 would need to be 47uF.

 
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vendaf

Jul 26, 2012
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How about output current that can reach at least 1-1.5A? Is it possible?

 

Hero999

Oct 28, 2007
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vendaf said:
How about output current that can reach at least 1-1.5A?
What do you think?

Is it possible?
I didn't say it's impossible, just that it isn't practical. It's theoretically possible. Do the calculations and you'll see what I'm getting at.
 
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audioguru2

Apr 6, 2004
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The capacitor will have AC across it, not DC so you cannot use a polarized electrolytic capacitor.

I could not find a film capacitor rated at 47uF/400VAC anywhere. They were available 60 years ago, were very large and very expensive. But transformers are inexpensive and are available everywhere today.

 
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