Power question

[scherzo]

I've noticed that the majority of systems here either take 5v or 8v. And in order to get a steady voltage, you need to have a battery that has a significantly higher voltage and run it through either a 7805 or 7808. Correct me if I'm wrong please.

Now, I recent picked up this little 1GB mp3 player that isn't much bigger than those keychain/thumb drives that you stick directly into an mp3 port. In fact, you stick this mp3 player directly also. I'm liking it.

What baffles me is that it only requires 1 AAA battery. It can't possibly be running at less than 1.5v, right? There must be a component (little transformer?) that is stepping up the voltage to 5v, I guess. And something like this wouldn't waste power by giving off heat like the 780X does.

Oh, and on this single AAA battery, it runs for 8 hours and the output is damn loud in my headphones.

Can someone help me understand this and tell me if it's possible to do something similar in a portable project?

Thanks

[Sparkfist]

The perpose of a 78xx is merly to regulate an output from a higher input. But this isnt necessary all the time. The Mp3 play might have been able to run on 1.x volts and that enough. Just remember that its a solid state device and so doesnt need a lot of voltage or currect as all your doing is reading like ram or rom, no motor not power suck.

[scherzo]

I see. Yeah, I guess you're right. The curiousity was just killing me. Thanks.