Stylus Vs. Digitizer Pens
By Aaron Parson
, last updated March 13, 2012
Though both touch screens and digitizers operate using pens, the two work very differently. Styluses, used with touch screens, contain no specialized circuitry, but simply act as a source of pressure, or, in the case of capacitive touch screens, conductivity. Digitizers, which offer much greater accuracy and pressure sensitivity, interact directly with digitizer pens to locate the nib as it moves above the surface of the digitizer. Because of these differences, the various types of input pens are not interchangeable.
Basic stylus pens used with touch-screen devices consist of little more than a plastic nib attached to a handle. These styluses work with resistive touch screens, which contain a two-layer surface. When you apply pressure to a spot on the screen, the two layers connect, sending a signal to the device. This technology works with any source of localized pressure and so does not require any circuitry in the stylus itself.
Digitizers use one of two types of pens. Active digitizer pens contain a battery and send constant signals to digitizer tablets locating them spatially. This provides an accurate location of the digitizer pen even when the pen is lifted above the surface of the tablet. Passive digitizer pens do not emit signals, but provide a similar function using signals put out by the surface of the tablet itself. Digitizers also include technology to sense the pen's pressure, simulating the effect of various pressure levels on paper.
Any source of pressure, be it a stylus, digitizer pen or even a fingernail, will activate a resistive touch screen. However, using devices other than the manufacturer's stylus might damage the screen. Unlike touch screens, digitizers are designed to recognize a specific model of pen, and so will not function correctly with alternate pens. Using a stylus on a digitizer will have no effect.
Capacitive Stylus Pens
Capacitive touch screens, often found in tablets and smartphones, operate differently than resistive touch screens and require the conductivity of a finger instead of a plastic stylus. Users desiring a stylus input on capacitive touch screens must buy a capacitive stylus. This type of stylus has a large, soft tip that simulates the touch of a finger and works exclusively with capacitive touch screens.