Graphic tablet

Graphics tablet is a hardware or computer input device that allows the wearer to draw by hand and insert a picture or sketch directly into the computer, like drawing on paper using pencil.

Operation

Passive Tablets
Passive tablet, which was introduced by Wacom, using electromagnetic induction technology, where the horizontal and vertical wires of the tablet operating as a sender and receiver rolls (coils). Tablet generate electromagnetic signals, received by the LC circuit in the pen. Cable in the tablet then change the mode of receiving and reading the signals raised by the pen.

Active Tablet
The difference lies in the passive tablet stylus. Active stylus on the tablet strength depends on the internal battery, not on tablets. This pen to create his own energy (self-powered) to then generate a signal on the tablet. By removing the obligation to supply energy to the pen, it means that the tablet will be able to obtain a constant signal to the pen, because he did not have to replace the signal and receiver modes, thus sending a signal will be more efficient.

Source : www.wikipedia.com