In-car power supply

Miscellaneous
1

Hi all (ones with more electronics knowlege than me!)

I want to build a car charger for a friend’s mp3 player.

It says it need 5v (I think about 400-500 ma).

Is it OK if I just use a 7805 directly from the car’s lighter-outlet or are there any dangers I should consider? maybe i need some filter caps?

any advice is welcome!

Thanks , uclaros

2

Yeah, definitely with filter caps. A recitifer is not needed (it´s really hard to change the polarity there).

Just use the schematic of the core or so.

Easy one! Just *do* use a heatsink! 12V to 5V @ 500 mA are appr. 3 Watts heat! That´s really much for such a little 78xx.

Greets!