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How to transform 12v 6w into 5v 1A? Answered

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FarmerKJS

3 years ago

The easiest would be to tear apart a usb car charger

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Yonatan24FarmerKJS

Answer 3 years ago

I actually don't recommend that, These car chargers work only at ~14V, Use a LM7805 or a cheap eBay variable transformer

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-max-Yonatan24

Answer 3 years ago

Why not? That is what I have done. I use them as basic "BECs" on my quadcopter! And the one I have torn down, a dollar store cheapie, works down to around 7V before it is no longer able to regulate properly. A 780 regulator is NOT suitable for his application because his power supply is 6W maximum. A 7805 will draw 12W for the 5V 1A output.

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-max--max-

Answer 3 years ago

Although, to be fair, 6W *might* not be enough many buck converters. It would have to be rated at least 83.3% efficiency under full load. (6W in, 5W out). That is do-able, but I am not sure if the cheap buck converters in car phone chargers are that efficient under full load.

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steveastroukYonatan24

Answer 3 years ago

That's a neat trick. A car battery is nominally 12V, 14 only when absolutely fully charged, and then only briefly. And a variable transformer only works on AC

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iceng

3 years ago

1) A six watt input provides a current of Amps = w/v = 6/12 = 1/2A

2) A linear regulator like the 7805 cannot create additional current beyond o.5A

3) You want a 5 watt output = VxA = 5x1

4) A switcher that is 90% efficient (doubtful) would probably do your transform.

5) could you be mistaken about the 6w ?