Car Adapter Voltages

I have a portable MP3 player with a 5.0 volt DC input battery charger.

I have a car DC adapter, with 4.5 and 6.0 volt DC outputs (no 5.0 volts).

Can I 'successfully' use the 4.5 or 6.0 volt car adapter to power the

Thank you in advance.

Assuming the 4.5 and 6V adapters truly give you those voltages, and assuming they provide enough current for the MP3 player: You might get away with using the 4.5 volt adapter. The 6V adapter will work if you put a diode in series with it.

However - you probably could make an adapter the you KNOW will work at very little cost. Post the current requirements for the MP3 and the current specs for the charger and we'll tell you how. My guess is that the MP3 has very low current requirements < 50 mA - in which case a cigarette lighter plug, some wire and a 7805 is all you need.