A stylus is a pen-like accessory that’s used to perform touch commands on certain touchscreen devices. As shown in the image to the left, it looks like an ordinary pen, even featuring a narrow tip that resembles the pen’s writing head. However, it doesn’t actually contain ink. Rather, most styluses are made entirely of plastic.
But it’s important to note that not all touchscreen devices support the use of a stylus. If you have a smartphone, for example, try tapping the screen with a stylus or even a closed pen and you’ll probably discover that it doesn’t register your touch command. Although there are exceptions, most smartphones don’t support the use of a stylus. So, what type of touchscreen devices can you use a stylus to control?
Resistive Touchscreen Devices
The reason most smartphones don’t support styluses is because they use capacitive touch-sensing technology. Capacitive touchscreen devices identify touch by measuring capacitance. Touching the surface of a capacitive device allows your finger to absorb some of the device’s electrostatic field. It’s not enough to cause any noticeable shock, yet it’s still enough for your finger — or any other part of your body — to absorb. Capacitive devices constantly measure their uniform electrostatic field, looking for changes that indicate a touch command.
Resistive touchscreen devices, on the other hand, do support styluses. Unlike capacitive devices, resistive devices don’t identify touch commands by measuring capacitance. Rather, they identify touch commands by pressure. Touching the surface of a resistive touchscreen device will force the upper layer to press against the bottom layer. As these two layers touch, resistive devices are able to pinpoint the location of the user’s touch command. This format allows you to control resistive devices using a bare finger, gloved finger or stylus.
Capacitive Touchscreen Devices With Capacitive Stylus
While most capacitive touchscreen devices don’t support styluses as a method of input, there is an exception: capacitive stylus. A capacitive stylus is a special type of stylus that features a conductive tip. Therefore, it’s able to absorb some of a capacitive touchscreen device’s electrostatic field — just like your own bare finger would.
To recap, resistive touchscreen devices generally work with a stylus, whereas capacitive devices do not. The only time when a capacitive device will work with a stylus is when you are using a capacitive stylus. For standard styluses that don’t feature a conductive tip, you won’t be able to use them to control a capacitive touchscreen device.