Bruce Johnson wrote: > > On May 17, 2009, at 7:34 AM, William Gates wrote: > >> What makes you think that the port can only accept DC current? >> Did apple ever make any educational rack charging stations? I think I >> remember something about them but I'm not sure? > > > > Because if the iBook could convert AC to DC internally, we'd just use > a regular power cord for it instead of a power brick.
Converting AC to DC is not the same as converting 120V to 24V. If it did have exposed contacts on the outside of the case that would charge the battery it's very likely there was a single diode or four diodes in a bridge configuration to isolate the battery from the contacts. Otherwise the battery could be shorted out - BAD. Normally external power goes through a power management unit that routes power to the laptop and to/from the battery. But it's possible in this application the battery might be connected more directly > > I very vaguely remember seeing a cart for iBooks once upon a time. > There was. At school we occasionally considered getting a couple of these racks. They can be rolled from classroom to classroom. The problem we worried about was that teacher wouldn't plug in the rack to make sure all the laptops were charged up for the next class. That and we heard stories of the laptops getting trashed in pretty short order. It was a cart that held the laptops and charged them. There was a single cord to plug it into wall power and it may have had provisions for an Airport base station to provide a WiFI connection. -- Clark Martin Redwood City, CA, USA Macintosh / Internet Consulting "I'm a designated driver on the Information Super Highway" --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to Low End Mac's G-Books list, a group for those using G3 iBooks and PowerBooks (we run a separate list for G4 'Books). The list FAQ is at http://lowendmac.com/lists/g-books.html and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/g-books?hl=en Low End Mac RSS feed at feed://lowendmac.com/feed.xml -~----------~----~----~----~------~----~------~--~---
