I got a Creative MuVo TX FM mp3 player yesterday for my birthday. I listen to it alot at my desk and i want to create a place where i can listen without using the battery. I only have a 3 volt ac-dc and i need it to be 1.5 volts to power the mp3 player. So i would like to know what resistor i should use to bring it down to 1.5 volts. Let me feel you guys in on some info: 1. The MP3 Player connects to the battery through a usb connector. 2. it wont play when given 3 volts 3. it knows it is plugged into the computer when given 5 volts 4. It will only work when given 1.5 volts So if you could please tell me what resistor to use or some alternative method to do this.
Find out the resistance of the MP3 player using a multimeter and put the equivalent resistance in series on the line...unless it varies then I don't know what to do. See siggy
Regular silicon diodes, like the classic 1n4001 have a .7v voltage drop. Put 2 in series with the MP3 player, and it gets 1.6V (if the adaptor really puts out 3V...) I think that should be close enough. If not you can get a LDO (low Drop out) 1.5v regulator. Digi-key part no: RC1587T15-ND looks promising, A TO-220 case and a 3A rating, overkill yes, but it is cheaper than some of the other regulators. How much power does the muvo need? Because that is how many watts the regulator will dissipate. (since the regulator eats 1.5v and the muvo eats the other 1.5v) I dont think it will be that much, so you might be able to get away with no heat sink. Just get the regulator, and 2 capacitors, something to mount them on, and you should be good.
