A user is unable to use a drawing stylus on a smartphone.

A digitizer is a device that converts analog signals, such as touch or pressure, into digital signals that can be processed by a computer. A digitizer is usually embedded in the screen of a smartphone or tablet, and it works with a compatible stylus to enable drawing and writing on the screen1.

There are different types of digitizers and styluses, such as capacitive, resistive, active, and passive. Capacitive digitizers and styluses work by detecting changes in the electric field on the screen when the stylus touches it. Resistive digitizers and styluses work by detecting changes in the resistance on the screen when the stylus presses it. Active digitizers and styluses work by using an electromagnetic field to communicate between the stylus and the screen. Passive digitizers and styluses work by using a special material on the tip of the stylus that mimics the human finger2.

Not all digitizers and styluses are compatible with each other. For example, an active stylus will not work with a capacitive or resistive digitizer, and vice versa. A passive stylus will work with any digitizer, but it will not have any advanced features, such as pressure sensitivity or tilt control2.