Your audio amp looks like it wants 5V. PIC wants....5V? or 3.3V? Simply way is use a 9V wall wart or such and a 7805 with a few caps, then use an LDO for the MP3 player, feeding off the 5V regulated. Not an efficient way to do it perhaps, but an easy way. You need at least 6-7V for the 7805 to regulate, as it needs a little bit of head room for it. Else you could use a LDO for that as well, and not need quite that much above the 5V. You didnt mention how much current the audio amp needs...since its running off batteries I assumed it doesn't pull alot -AS Alison Lewis wrote: I would like to flip a switch and have everything powered. I have: (1) A MP3 player that runs on 1 AAA Battery (1.5V) RIO FUSE (2) Pic Chip with one sensor (3) Audio Amplifier that uses 4 AAA Batteris with speakers (http://www.si-technologies.com/frontEnd/cm_productDetail.jsp?productID=28) Want them all to run off power from the wall. Should I just get three different power adapters one for each device? (which is impossible for the MP3 player)or can I make them run off of one power supply? How does one start to think about what is needed? Are there any good power tutorials out there? --- Thank for any information ---- __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --------------------------------- Start your day with Yahoo! - make it your home page -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist