78Views3Replies

Author Options:

USB port devices?. If the computer must be plugged-in, why not plug into AC directly? Can someone clarify this for me? Answered

.

Tags:USB

Discussions

0
karnuvap
karnuvap

10 years ago

These previous answers seem to ignore the fact that you would want to charge-up a USB charged MP3 player and firing up the PC to do this is somewhat wasteful. You could try a wall-wart but there is sometimes a problem with these in that the MP3 player doesn't understand that it can be charged without being connected to a PC and it shuts down if it doesn't get the right signals on the data pins of the USB port. This is less of a problem these days as manufacturers realise this might happen but for the older devices there is no alternative to plugging them into a live PC. Sorry

0
orksecurity
orksecurity

10 years ago

In most cases, just convenience. As dilandou said, generally these are things which have to be wired to the computer anyway, and it's easier to run that one wire than to have to run that *and* a power cord (and find somewhere to plug in -- my own PC's power strips, plural, are pretty full.)

0
dilandou
dilandou

10 years ago

For starters, most USB devices add features to a computer, making it somewhat moot to power them without the computer being powered up. If you did want to power them without a machine you'd need to convert the AC power, be it 110/120 or 230/240 volt, to 5 volt DC. There are wall warts you can get that have usb sockets on them for charging devices through usb, such as phones and mp3 players etc.