There are two methods by which laptop chargers achieve their end-goal (to power the laptop). Firstly they can and are used to power laptops directly, in this way no power from the laptop battery is used. The other method is to charge the laptop battery so that the laptop has a constant power supply even when it is not connected to mains electricity. Of course the charge in the battery will eventually run out but that is something that one has to live with (of course one may have two batteries or a whole pack of batteries). One major problem with laptop chargers is that they are usually unique to a single type or a single line of laptops. What this means is that it is highly unlikely that a charger for an Acer Gateway laptop to work with a Sony Vaio laptop. Part of the reason is that different models have different power requirements due to differences in the display size, the number of hard disk drives, CD/DVD drives, graphics/sound cards, the processor, etc. The other reason simple seems to be that manufacturers want to sell over-priced chargers to increase their profits. There are however some universal chargers available that have compatibility that extends to various manufacturers' laptops. While one of the most popular type of laptop accessories are keyboards, laptop chargers are not far behind.

Accessories for the following laptop manufacturers are available at PDA Accessories: Acer, Averatec, BenQ, Canon, Dell, Fujitsu, Gateway, Hitachi, HP, iBooks by Apple, JVC, Mitsubishi, NEC, Nikon, Sony, Toshiba, Trigem, Viewsonic, WinBook, etc.