The touch pad on a laptop. The touch pad or track pad is a touch input device that can control a cursor or facilitate navigation through a menu or graphical interface.

Most of the Touch pads are usually located at the bottom of the laptop keyboard and make the function of the mice of the desktop. They are usually rectangular in shape and accompanied by 1, 2 or more buttons that represent the buttons on a mouse.

The technology of touch Touch pads also appeared in 2002 in the portable MP3 player from Apple, the second-generation iPods, but in a circular shape.
The touch pad is made by a grid of two layers of strips of electrodes, one vertical and one horizontal, separated by an insulator and connected to a sophisticated circuit. The circuit is responsible for measuring the capacity between each electrode and each electrode vertical horizontal. A finger near the intersection of two electrodes modifies the capacity between them to modify the dielectric properties of their environment. The finger has very different dielectric properties of air.

The position of the finger is calculated accurately based on the variations of the mutual capacity at various points to determine the Centro of the contact surface. The resolution of this system is impressive, up to 1 / 40 mm. Also can be measured also the pressure is done with the finger. You can not use pencils or other non-conducting materials such as pointers. It is very resistant to the environment, well supported by dust, humidity, static electricity, etc.. There was light, thin and can be flexible or transparent.