Types of Power Supplies
Three primary types of power supplies are used for laptops: ac adapters, dc adapters and inverters. Each is different in what it does, and the selection of the appropriate one is dictated by the nature of the power supply that is available for use.Laptop Travel carries a complete line of laptop power adapters, AC, auto and auto/air adapters, for Apple, Compaq, Dell, Gateway, HP, IBM, Sony, Toshiba and many other laptop and notebook brands. Click here to select your laptop model from the drop down menu for a list of avaliable power supplies and power adapters for your laptop. See below for more information about each type of power supply.
AC and DC Power
Laptops, many printers and other computer peripherals require direct current (DC) electricity. DC power is produced by batteries and occurs in nature in static or lightning, but it is not the type of power that is generally available in home and office electric outlets. These generally provide alternating current (AC) electricity, the type used by most household appliances.
AC Adapters
Laptops and other DC devices generally have two common characteristics: the ability of the device to run on batteries and the presence of a small power “brick” outside the device that powers it. They cannot be used with AC power unless the power is “converted” before use. Their power "bricks" are really DC power supplies that convert the AC power from the wall socket into the DC power required for the device. They are often called AC Adapters or chargers (because of their function of charging the internal laptop battery), and have an electric plug for the wall socket on one end and a special connector for plugging into the laptop or other device on the other end.
DC Adapters
Auto batteries, in-flight power systems and solar power systems are common sources of DC power. Although they produce the DC power used by laptops and other DC power devices, they generally produce voltage that is below what is required by many such DC devices. (For example auto batteries usually produce 12V, which is below the voltage required by most laptops.) Thus DC adapters are necessary to adapt the voltage coming from the power source to the voltage that is required by the laptop or other DC device. They have a DC input plug such as a cigarette lighter plug on one end and a special connector for plugging into the laptop or other device on the other end.
Inverters
Inverters are used to change DC power into AC power for use by all electric appliances and electronics. This is generally done by plugging the inverter into the DC source (typically a cigarette lighter receptacle) and providing in the body of the inverter one or more standard household electric sockets. The advantage of an inverter is that it can be used to provide power for ANY device because it is basically supplying a standard AC socket. The disadvantages of an inverter are that the power conversion process is not as efficient as the DC adapter process and that as a rule inverters are larger and heavier than DC adapters.
