Have you ever tried to control a touchscreen device using a stylus, only to discover that it doesn’t work? You aren’t alone. Many people assume that their smartphone, tablet computer or other touchscreen device will support a stylus. If you can control a touchscreen device using your finger, conventional wisdom may lead you to believe that a stylus will work as well. Depending on the specific type of touchscreen device, though, this isn’t always the case. Some touchscreen devices simply won’t work with a stylus.

Capacitive Touchscreens Don’t Work With Styluses

Capacitive touchscreens, the most common type, don’t work with styluses. You can control them using a bare finger (or multiple fingers), but you can’t control them using a stylus. This is because capacitive devices identify touch by looking for changes in capacitance. There are two specific types of capacitive touchscreen technology: projected capacitive and surface capacitive. And while they have subtle nuances, they both create an electrostatic field on that surface, and when you touch this field, it absorbs some of the electricity. Capacitive touchscreen devices are then able to determine where exactly you touched.

A stylus won’t work with a capacitive touchscreen device because styluses aren’t conductive. The human body is an excellent conductor of electricity. When you touch a capacitive device, your finger absorbs some of the electricity, thereby allowing the device to identify the point of contact. Unfortunately, a stylus isn’t able to absorb electricity — it’s not conductive — so it won’t work with capacitive devices. You can generally only control capacitive touchscreen devices using a bare finger.

Resistive Touchscreens Do Work With Styluses

You can’t use a stylus to control a capacitive touchscreen device, but you can use it to control a resistive touchscreen device. Resistive touchscreen devices feature an entirely different design that identifies touch commands based on pressure rather than changes in capacitance. They feature multiple layers that, when pressed together, signal a touch command. Therefore, you can use either a bare finger or stylus to control resistive touchscreen devices. Any object or body part will essentially press the layers together and render a touch command.

Capacitive Stylus

There’s an exception to the “you can’t use a stylus with a capacitive touchscreens” rule. While most styluses are made of hard plastic, some are made of a conductive material so that they’ll work with capacitive devices. Aside from this special type of stylus, though, you can’t use a traditional stylus to control a capacitive touchscreen device.