Computer laptops add convenience and mobility to computers. A laptop, known also as notebook computer or notebook, is basically a small mobile computer, which usually weighs 2.2-18 pounds (1-6 kilograms), depending on factors like size, materials etc.

With their mobile nature, laptops are powered by a single main battery or they are powered from an external AC/DC adapter.
The advantage of the external AC/DC adapter is that it can simultaneously charge the battery and supply power to the computer itself.  If there is a failure in the power supply, many laptop computers are equipped with a 3 volt cell that runs the clock and other processes.

In general, laptops are usually not as powerful as a desktop computer but tend to cost the same.  Though not as powerful, laptops are capable of the same tasks as a desktop computer.  Other similarities between the desktop and laptop computer are that they contain much of the same components except the components of the laptop are miniaturized and optimized for mobile use and efficiency of power consumption.

Laptops usually have liquid crystal displays and most of them use different memory modules for their random access memory (RAM), for instance, SO-DIMM in lieu of the larger DIMMs. In addition to a built-in keyboard, they may utilize a touchpad (also known as a trackpad) or a pointing stick for input, though an external keyboard or mouse can usually be attached.