In electrical engineering, capacitive sensing (sometimes capacitance sensing) is a technology, based on capacitive coupling, that can detect and measure anything that is conductive or has a dielectric constant different from air. Many types of sensors use capacitive sensing, including sensors to detect and measure proximity, pressure, position and displacement, force, humidity, fluid level, and acceleration. Human interface devices based on capacitive sensing, such as touchpads,[1] can replace the computer mouse. Digital audio players, mobile phones, and tablet computers will sometimes use capacitive sensing touchscreens as input devices.[2] Capacitive sensors can also replace mechanical buttons.
A capacitive touchscreen typically consists of a capacitive touch sensor along with at least two complementary metal–oxide–semiconductor (CMOS) integrated circuit (IC) chips, an application-specific integrated circuit (ASIC) controller and a digital signal processor (DSP). Capacitive sensing is commonly used for mobile multi-touch displays, popularized by Apple's iPhone in 2007.[3][4]