How does a graphic tablet work?

Answer 1

The stylus looks and feels like a pen yet contains no batteries or magnets. Instead it takes advantage of electro-magnetic resonance technology developed by WACOM Co Ltd in which radio waves are sent to the stylus and returned for position analysis. In operation a grid of wires below the screen alternates between transmit and receive modes roughly every 20 microseconds.

The electro-magnetic signal simulates oscillation in the coil and capacitor resonant circuit in the pen. The resonant circuit in the pen's tip supplies the power and serves as a transmitter too.

The received signal goes through the modulator to the chip. The information of the pressure sensor (capacity) and of the side switch are going to the chip first. Then the information is sent back to the modulator which in turn sends a signal to the resonant circuit in the tip.

The tablet picks up the information in the pens tip in order to determine position and other information like pressure.

Since the grid provides the power to the pen through resonant coupling, no batteries are required. Thus there are no consumables inside the pen that will run down and need to be replaced or extra items which could make the pen top-heavy.

Answer 2

You use the tablet to "draw" whatever you want to imput into a computer. You use a stylus to draw upon the surface.