Touchpad

A touchpad, also called a trackpad, is a pointing device whose largest component is a tactile sensor, an electronic device with a flat surface that detects the position and motion of a user's fingers and translates them into two-dimensional motion that controls a pointer on a graphical interface. Touchpads are the standard pointing device on laptop computers, where mice are less practical, and are also used on some desktop setups with limited desk space, on personal digital assistants, and on portable media players, because they can be made small; detached wireless touchpads and touchpads built into external keyboards are also available. The most common type, the capacitive touchpad, cannot sense a pencil tip or another ungrounded implement and may not respond reliably to a gloved hand.