Have you heard of capacitive coupling? It’s the underlying principle behind capacitive devices. Capacitive devices are touchscreen devices like tablets, smartphones and even switches. They support touch-based commands by measuring changes in capacitance. While available in different types, capacitive devices leverage an electrical phenomenon known as capacitive coupling. With capacitive coupling, they are able to detect commands performed with a conductive object.
The Basics of Capacitive Devices
Capacitive devices are characterized by their ability to measure changes in capacitance. When you turn on a capacitive field, it will apply a voltage to the interface surface. The interface surface may consist of a touchscreen display, such as that of a tablet or smartphone, or the interface surface may consist of a switch or button. With a voltage applied to this surface, the capacitive device will measure it.
What Is Capacitive Coupling?
Capacitive coupling is an electrical phenomenon that allows capacitive devices to detect touch commands performed with any conductive object. As long as you touch a capacitive device with a conductive object, it will register your touch command. Conductive objects, of course, are characterized by their ability to transmit electricity. Electrically can easily flow through conductive objects with minimal resistance.
There are different types of capacitive devices, some of which include surface capacitance, mutual capacitance and self-capacitance. Regardless, they are all able to detect touch commands performed with a conductive object. They typically feature a top layer with a conductive coating or patterned electrodes. During use, capacitive devices will apply a voltage to this top layer, which they will constantly measure for changes in capacitance.
If you touch the interface of a capacitive device with a conductive object, you’ll draw some of the electricity to the conductive object. Conductive objects are, of course, electrically conductive. Therefore, touching the interface will cause some of the capacitive device’s electricity to travel to the conductive object. The capacitive device will identify this change of capacitance, and it will respond with the appropriate action.
Resistive Touchscreens and Capacitive Coupling
Capacitive coupling is exclusive to capacitive devices. Resistive touchscreens aren’t classified as capacitive devices. They can still detect touch commands, but resistive touchscreens use a completely different technology than capacitive devices.
Resistive touchscreens leverage pressure to detect touch commands. They feature multiple layers, which are separated by default. Pressing the top layer will push it into the bottom layer, in which case the resistive touchscreen will register your touch command.